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HYDROGEN CYANIDE

Human Health Effects:

See Occupational Exposure Standards

Human Toxicity Excerpts:

SYMPTOMS OF ... POISONING APPEAR WITHIN ... SECONDS TO MIN AFTER INGESTION OR BREATHING VAPORS ... THEY CONSIST OF GIDDINESS, HYPERPNEA, HEADACHE, PALPITATION CYANOSIS, & UNCONSCIOUSNESS. ASPHYXIAL CONVULSIONS MAY PRECEDE DEATH.
[Goodman, L.S., and A. Gilman. (eds.) The Pharmacological Basis of Therapeutics. 5th ed. New York: Macmillan Publishing Co., Inc., 1975. 904]**PEER REVIEWED**

SYMPTOMATOLOGY: 1. Massive doses may produce, without warning, sudden loss of consciousness and prompt death from respiratory arrest. With smaller but still lethal doses, the illness may be prolonged for 1 or more hours. 2. Upon ingestion, a bitter, acrid, burning taste is sometimes noted, followed by a feeling of constriction or numbness in the throat. Salivation, nausea and vomiting are not unusual ... 3. Anxiety, confusion, vertigo, giddiness, and often a sensation of stiffness in the lower jaw. 4. Hyperpnea and dyspnea. Respirations become very rapid and then slow and irregular. Inspiration is characteristically short while expiration is greatly prolonged. 5. The odor of bitter almonds may be noted on the breath or vomitus ... 6. In the early phases of poisoning, an increase in vasoconstrictor tone causes a rise in blood pressure and reflex slowing of the heart rate. Thereafter the pulse becomes rapid, weak, and sometimes irregular ... A bright pink coloration of the skin due to high concentrations of oxyhemoglobin in the venous return may be confused with that of carbon monoxide poisoning. /Cyanide/
[Gosselin, R.E., R.P. Smith, H.C. Hodge. Clinical Toxicology of Commercial Products. 5th ed. Baltimore: Williams and Wilkins, 1984.,p. III-126]**PEER REVIEWED**

SYMPTOMATOLOGY: 7. Unconsciousness, followed promptly by violent convulsions, epileptiform or tonic, sometimes localized but usually generalized. Opisthotonos and trismus may develop. Involuntary micturition and defecation occur. 8. Paralysis follows the convulsive stage. The skin is covered with sweat. The eyeballs protrude, and the pupils are dilated and unreactive. The mouth is covered with foam, which is sometimes bloodstained ... The skin color may be brick red. Cyanosis is not prominent in spite of weak and irregular gasping. In the unconscious patient, bradycardia and the absence of cyanosis may be key diagnostic signs. 9. Death from respiratory arrest. As long as the heart beat continues, prompt and vigorous treatment offers some promise of survival. /Cyanide/
[Gosselin, R.E., R.P. Smith, H.C. Hodge. Clinical Toxicology of Commercial Products. 5th ed. Baltimore: Williams and Wilkins, 1984.,p. III-127]**PEER REVIEWED**

... ONLY OCCASIONALLY HAS REFERENCE BEEN MADE TO IRRITATION OF EYE, CONJUNCTIVITIS, OR SUPERFICIAL KERATITIS DEVELOPING AFTER CHRONIC EXPOSURE TO HYDROGEN CYANIDE GAS.
[Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986. 289]**PEER REVIEWED**

... WORKERS EXPOSED FOR PERIODS OF ... 7 YEARS AT CONCN BETWEEN 4 & 12 PPM ... /SHOWED/ INCREASE IN SUBJECTIVE SYMPTOMS SUCH AS HEADACHE, WEAKNESS, CHANGES IN TASTE & SMELL, IRRITATION OF THROAT, VOMITING, EFFORT DYSPNEA, LACRIMATION, ABDOMINAL COLIC, PRECORDIAL PAIN & NERVOUS INSTABILITY.
[American Conference of Governmental Industrial Hygienists. Documentation of the Threshold Limit Values and Biological Exposure Indices. 5th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, 1986.314]**PEER REVIEWED**

ENLARGEMENT OF THYROID GLAND, ATTRIBUTED POSSIBLY TO EFFECTS OF THIOCYANATE, CHIEF METABOLITE OF CYANIDE, WAS REPORTED ... /IN WORKERS EXPOSED OVER A PERIOD OF YEARS TO LOW CONCENTRATION IN AIR/.
[American Conference of Governmental Industrial Hygienists. Documentation of the Threshold Limit Values and Biological Exposure Indices. 5th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, 1986.314]**PEER REVIEWED**

Two episodes of cyanide poisoning occurred children who exhibited typical signs and symptoms of cyanide poisoning 2 hr after ingestion of a large amount of apricot kernels; 7 children recovered and 1 died soon after admission. The second episode involved 16 children who had eaten a sweet prepared from kernels. Symptoms and signs were identical to those in the first group but appeared 0.5 hr after ingestion and were more severe. Thirteen children recovered, 2 died shortly after admission and a third child died 2 hr later. Apricot kernals contain a cyanogenic substance called amygdalin, which after hydrolysis, liberates hydrocyanic acid. This activation usually only occurs after ingestion. In the second episode hydrolysis probably occurred during the preparation of the sweets, explaining the short interval between ingestion and appearance of the signs of poisoning.
[Lasch EE, El Shawa R; Pediatrics 68 (1): 5-7 (1981)]**PEER REVIEWED**

Chronic exposure may cause fatigue, weakness.
[The Merck Index. 10th ed. Rahway, New Jersey: Merck Co., Inc., 1983. 696]**PEER REVIEWED**

Liquid hydrogen cyanide ran over the bare hand of a worker wearing a fresh air respirator. Cyanide inhalation was prevented, but the worker collapsed into deep unconsciousness within five minutes, suggesting significant percutaneous absorption. /Liquid hydrogen cyanide/
[Potter AL; Br J Ind Med 7: 125 (1950) as cited in USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-8 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Two signs associated with cyanide poisoning in man: ... (1) the failure to utilize molecular oxygen in peripheral tissues results in abnormally high concn of oxyhemoglobin in the venous return, which accounts for a flush or brick-red skin; And (2) attempts to compensate for the inhibition of oxidative metabolism leads to increased demands on glycolysis, which accounts for a metabolic (lactic) acidosis.
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-17 (1980) EPA 440/5-80-037]**PEER REVIEWED**

An outbreak of spastic paraparesis, which mostly affected women and children, occurred in a northern province of Mozambique in 1981. The epidemic was related to chronic cyanide intoxication associated with a diet consisting almost exclusively of cassava. A prolonged drought in the area had exhausted all food resources except cassava, especially the bitter varieties. A nutritional, toxicological, and botanical investigation was carried out in 2 of the 5 districts affected. The main findings were that cyanide levels were unusually high in the cassava plant as a consequence of the drought with daily intakes estimated at 15-31.5 mg hydrogen cyanide. Detoxification of the bitter varieties by sun-drying was inadequate because of the general food shortage and metabolic detoxification was probably reduced owing to the absence of sulfur-containing amino acids in the women and children. The nutritional status of the population, however, was not very poor and symptoms of advanced undernutrition were rarely seen.
[Bright J, Marrs TC; Hum Toxicol 3 (6): 521-22 (1984)]**PEER REVIEWED**

A STUDY WAS UNDERTAKEN TO ASSESS THE HEALTH STATUS OF WORKERS EXPOSED TO CYANIDE FUMES & AEROSOLS IN A FACTORY DURING ELECTROPLATING AND CASEHARDENING JOBS. CYANIDE LEVELS WERE MEASURED IN THE WORK ENVIRONMENT & IN BLOOD & URINE. SMOKERS HAD HIGHER CONCENTRATIONS THAN NON-SMOKERS. THE HIGHEST LEVELS WERE 0.8 & 0.2 MG/CU M IN BREATHING ZONE & GENERAL WORKROOM ATMOSPHERE, RESPECTIVELY. THE WORKERS COMPLAINED OF TYPICAL CYANIDE POISONING IN SPITE OF THE LOW CONCN. ... /CYANIDES/
[CHANDRA H ET AL; J ANAL TOXICOL 4 (4): 161-65 (1980)]**PEER REVIEWED**

A case of overexposure to hydrogen cyanide inside a 3500 gal tank which had contained a slurry of hydrazodiisobutyronitrile (which decomposed with water to give some hydrogen cyanide & acetone) is presented. This case is unusual in that survival without sequelae occurred despite exposure to HCN in the order of 500 mg/cu m for a six minute exposure, especially as treatment was not initiated until approximately 1 hr after exposure. Thus, survival with minimal sequelae can occur.
[Bonsall JL; Hum Toxicol 3 (1): 57-60 (1984)]**PEER REVIEWED**

... IT IS POSSIBLE FOR CYANIDE TO CAUSE BLINDNESS & TO DAMAGE OPTIC NERVES & RETINA. /CYANIDE/
[Grant, W. M. Toxicology of the Eye. 2nd ed. Springfield, Illinois: Charles C. Thomas, 1974. 334]**PEER REVIEWED**

Blood cyanide (HCN) or plasma thiocyanate (SCN) ... concentrations, or both, were measured in 30 patients (ages 11 months - 72 years) receiving Na nitroprusside (SNP) ... for 12 - 314 hr. Sequential measurements in 3 of these patients (infused 5, 12 and 13 days) showed that HCN concentrations varied with dose rate, while thiocyanate concentrations increased linearly with increasing Na nitroprusside dose. The accumulated data confirmed that the rate of administration (0.3 - 6.5 ug/kg/min) determined the plasma HCN concentrations (0 - 3.8 umol/l). Thus, if prolonged ... plasma HCN concentrations > 1 umol/l are to be avoided, the maximum safe sustained dose rate of Na nitroprusside will ... /be/ near ... 4 ug/kg/min.
[Vesey CJ, Cole PV; Br J Anaesth 57 (2): 148-55 (1985)]**PEER REVIEWED**

MOST SPECIFIC PATHOLOGICAL FINDING IN ACUTE CASES /OF CYANIDE POISONING/ IS BRIGHT RED COLOR OF VENOUS BLOOD. THIS IS STRIKING, VISIBLE EVIDENCE OF INABILITY OF TISSUE CELLS TO UTILIZE OXYGEN ... VENOUS BLOOD IS ONLY ABOUT 1 VOL % LOWER IN OXYGEN CONTENT THAN ARTERIAL BLOOD ... /CYANIDES/
[Clayton, G.D., F.E. Clayton (eds.) Patty's Industrial Hygiene and Toxicology. Volumes 2A, 2B, 2C, 2D, 2E, 2F: Toxicology. 4th ed. New York, NY: John Wiley & Sons Inc., 1993-1994. 3124]**PEER REVIEWED**

Cyanides are absorbed from the skin & mucosal surfaces and are ... dangerous when inhaled because toxic amt are ... absorbed through bronchial mucosa & alveoli. Symptoms, which /may/ occur ... are giddness, headache, palpitation, dyspnea, & unconsciousness. There may be some evidence of local irritation from the salts & nausea & vomiting. ... Central nervous depression. ... Early electrocardiographic changes may include atrial fibrillation, ectopic ventricular beats, and abnormal QRS complex with T wave originating high on the R wave. Sinus bradycardia is a common presenting sign. As cyanide levels in the blood rise, ataxia develops & is followed by coma, convulsions, & death. /Cyanides/
[Haddad, L.M. and Winchester, J.F. Clinical Management of Poisoning and Drug Overdosage. Philadelphia, PA: W.B. Saunders Co., 1983. 745]**PEER REVIEWED**

... HYDROGEN CYANIDE APPEARS TO BE LESS SELECTIVE THAN HYDROGEN SULFIDE IN TOXICITY TO THE CORNEAL EPITHELIUM, YET THESE SUBSTANCES ARE OTHERWISE ABOUT EQUALLY TOXIC ... HYDROGEN SULFIDE HAS BECOME ... HIGHLY SELECTIVE TOXICITY TO THE CORNEAL EPITHELIUM, BUT ONLY OCCASIONALLY HAS REFERENCE BEEN MADE TO IRRITATION OF EYE, CONJUNCTIVITIS, OR SUPERFICIAL KERATITIS DEVELOPING AFTER CHRONIC EXPOSURE TO HYDROGEN CYANIDE GAS.
[Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986. 289]**PEER REVIEWED**

WHEN ABSORBED, /CYANIDE/ ... REACTS READILY WITH ... CYTOCHROME OXIDASE IN MITOCHONDRIA; CELLULAR RESPIRATION IS THUS INHIBITED & CYTOTOXIC HYPOXIA RESULTS. ... RESPIRATION IS /INITIALLY/ STIMULATED ... A TRANSIENT STAGE OF CNS STIMULATION WITH HYPERPNEA AND HEADACHE IS OBSERVED; FINALLY THERE ARE HYPOXIC CONVULSIONS AND DEATH DUE TO RESPIRATORY ARREST. /CYANIDE/
[Gilman, A.G., L.S.Goodman, and A. Gilman. (eds.). Goodman and Gilman's The Pharmacological Basis of Therapeutics. 7th ed. New York: Macmillan Publishing Co., Inc., 1985. 1642]**PEER REVIEWED**

... ENLARGED THYROID GLANDS /WERE REPORTED/ IN WORKERS EXPOSED TO CYANIDE SALTS IN HEAT TREATMENT OF METALS. IT WAS SUGGESTED THAT ABSORPTION OF CYANIDE DUST & HYDROGEN CYANIDE PRODUCED BY HYDROLYSIS OF CYANIDE SALTS, WAS FOLLOWED BY METABOLISM TO THIOCYANATE, & THAT FAILURE TO ELIMINATE THIS ... CAUSED GOITROGENIC EFFECT. /CYANIDE SALTS/
[American Conference of Governmental Industrial Hygienists. Documentation of the Threshold Limit Values and Biological Exposure Indices. 5th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, 1986.153]**PEER REVIEWED**

HIGH CONCN PRODUCES TACHYPNEA (CAUSING INCREASED INTAKE OF CYANIDE); THEN DYSPNEA, PARALYSIS, UNCONSCIOUSNESS, CONVULSIONS, & RESPIRATORY ARREST. HEADACHE, VERTIGO, NAUSEA & VOMITING MAY OCCUR WITH LESSER CONCN. CHRONIC EXPOSURE ... MAY CAUSE FATIGUE, WEAKNESS.
[The Merck Index. 10th ed. Rahway, New Jersey: Merck Co., Inc., 1983. 696]**PEER REVIEWED**

Vapor (Gas) Irritant Characteristics: Vapor is not very irritating but is extremely poisonous; Liquid or Solid Irritant Characteristics: Liquid is not /very/ irritating but is extremely poisonous if absorbed through lung, skin, or eyes.
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

Both Laetrile and amygdalin-containing fruit pits /cherries, peaches, apricots, apples, and pears/ have been implicated as causes of acute cyanide poisoning in humans.
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-6 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Points of attack: Liver, kidneys, cardiovascular system, central nervous system.
[Sittig, M. Handbook of Toxic and Hazardous Chemicals and Carcinogens, 1985. 2nd ed. Park Ridge, NJ: Noyes Data Corporation, 1985. 508]**PEER REVIEWED**

VOLATILE /SRP: AIRBORNE/ CYANIDES RESEMBLE HYDROCYANIC ACID PHYSIOLOGICALLY, INHIBITING TISSUE OXIDN & CAUSING DEATH THROUGH ASPHYXIA. CYANOGEN IS PROBABLY AS TOXIC AS HYDROCYANIC ACID ... /CYANIDES/
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1839]**PEER REVIEWED**

Chemicals responsible for tissue hypoxia include carbon monoxide, hydrogen sulfide, and hydrogen cyanide. The major concern is the development of atherosclerosis followed by ischemic changes in vital organs such as the brain or heart. It is frequently difficult to prove that occupational factors are responsible for an individual illness, partly because the cardiovascular symptoms related to occupational exposures are often brought on by an underlying pathology which is not related to the job. However, it is sometimes possible to demonstrate a relationship between an increased occurrence of cardiovascular disorders and occupational factors among groups of workers. Cardiac disorders include coronary heart disease, cardiac arrhythmias, sudden death, chronic cor pulmonale, and disorders of the peripheral blood vessels such as secondary Raynaud's phenomenon. Careful questioning about the pattern of principal symptoms including chest pain, dyspnea, palpitation, syncope, cough, edema, and fatigue is the primary manner in which information about cardiovascular disorders is obtained. Information is frequently taken from a 12 lead electrocardiogram. (Ordinary chest radiographs may provide information concerning the presence of certain diseases of the heart and great vessels, but these are not generally useful in early detection).
[World Health Organization; Early Detection of Occupational Diseases p.236-238 (1986)]**PEER REVIEWED**

The excretion of hydrogen cyanide in breath and blood concentrations of cyanide were measured in eight normal subjects. There was no correlation between breath and blood levels of cyanide. Furthermore, breath cyanide concentrations calculated from blood values were much lower than measured values. When saliva was incubated at 37 deg C, hydrogen cyanide was formed in the presence of air but not in a nitrogen atmosphere. No hydrogen cyanide was formed with boiled saliva and the production of hydrogen cyanide from saliva was inhibited by catalase and by 6-N-phopyl-thiouracil. Centrifugation of saliva resulted in a supernatant and a sediment, which were both required for the formation of hydrogen cyanide. Dialysis of the supernatant abolished its cyanide forming ability, which could be restored by addition of thiocyanate.
[Lundquist P et al; Arch Toxicol 61 (4): 270-74 (1988)]**PEER REVIEWED**

Five patients with smoke inhalation from house fires presented to the hospital in a comatose state. Carboxyhemoglobin levels were elevated in all five patients, mean= 32% + or - 6. Arterial blood gases revealed the following means: pH 7.16 + or - 0.06; partial pressure of carbon dioxide 35 mm HG + or - 10.5; carbonate 12.6 mEq/l + or - 0.07; base excess -16 mEq/l + or - 1.58; partial pressure of oxygen 353 mm Hg + or - 149; oxygen saturation 66% 5.5. The patients were presumed to have both cyanide and carbon monoxide intoxication and were treated with the cyanide antidote kit and hyperbaric oxygen (HBO). Four of five patients awoke within 15 minutes of reaching maximum pressure and remained neurologically intact thereafter. The fifth patient died one week later. Cyanide blood levels drawn prior to treatment revealed a mean of 1.62 + or - 1.44 ug/ml. The highest blood cyanide level was 3.9 ug/ml (the death) and the lowest 0.35 ug/ml.
[Hart GB et al; J Emerg Med 3 (3): 211-16 (1985)]**PEER REVIEWED**

CYANIDES SUCH AS ... HYDROGEN CYANIDE, POTASSIUM CYANIDE AND SODIUM CYANIDE ARE ACUTELY POISONOUS, INTERFERING WITH METABOLIC PROCESSES & CAUSING RAPID DEATH. IN SEVERE POISONING, PUPILS ARE CHARACTERISTICALLY WIDELY DILATED.
[Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986. 287]**PEER REVIEWED**

Acute poisoning results in weakness, headache, confusion, and nausea and vomiting. Long term effects may include neurasthenia with autonomic nervous system involvement, psychic alterations, precordial pains, breathlessness on exertion, bradycardia, arterial hypotonia, polycythemia, dyspepsia, hepatic impairment, and thyroidal hypofuction.
[World Health Organization; Early Detection of Occupational Diseases 154-164 (1986)]**PEER REVIEWED**

In minimal lethal doses, cyanide affects primarily the central nervous system. Cyanide initially stimulates the peripheral chemoreceptors, causing increased respirations. It also promotes slowing of the heart by stimulating the carotid body receptors. The electrical activity of the brain may stop while the heart is still beating. /Cyanide/
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1478]**PEER REVIEWED**

Signs & symptoms of acute cyanide poisoning reflect cellular hypoxia & are often nonspecific. Onset of symptoms depends on dose, route, & duration of exposure. Inhalation produces ... flushing, headache, tachypnea, & dizziness ... irregular stridulous breathing, coma, seizure, & death ... /Cyanide/
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1478]**PEER REVIEWED**

The most common symptoms of a long-term cyanide exposure that has exceeded current standards have been headache, dizziness, nausea or vomiting, and a bitter or almond taste. Mild abnormalities of vitamin B12, folate, and thyroid function have been noted, but symptoms did not correlate with these changes. Other excessive exposures to cyanide have resulted in psychosis and thyroid enlargement without symptoms of thyroid dysfunction. Several clinical syndromes have been associated with chronic cyanide toxicity ... . These diseases may be due to high cyanide levels, impaired cyanide detoxification mechanisms, nutritional deficiencies, or some combination of these factors. /Cyanide/
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1479]**PEER REVIEWED**

In serious poisonings, the skin is cold, clammy, and diaphoretic. Cyanosis may be a late finding, since poor tissue utilization of oxygen results in elevated venous oxygen levels. Retinal veins and arteries may appear similar in color because of the elevated venous oxygen level. /Cyanide/
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1479]**PEER REVIEWED**

Depression of the cardiovascular system requires cyanide doses higher than those necessary for depression of the CNS. Initial tachycardia occurs followed by bradycardia.. Dysrhythmias and hypotension often precede peripheral vascular collapse. The ECG may display striking ischemic changes; pulmonary edema may complicate severe intoxications. /Cyanide/
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1479]**PEER REVIEWED**

The CNS is the most sensitive target organ of cyanide poisoning, with early stimulation followed by CNS depression. Early symptoms include lightheadedness, giddiness, tachypnea, nausea, vomiting, feeling of neck constriction and suffocation, confusion, restlessness, and anxiety. Initial tachypnea results from direct stimulation of carotid body chemoreceptors followed by respiratory depression. Severe cyanide poisonings progress to stupor, coma, opisthotonus, convulsions, fixed dilated pupils, and death. /Cyanide/
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997.,p. 1478-9]**PEER REVIEWED**

Cyanide is a potent oral poison producing symptoms in minutes and death in minutes to hours. One teaspoon of 29% liquid hydrogen cyanide has been fatal.
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1477]**PEER REVIEWED**

The release of excessive amounts of HCN gas into the breathing zone of workers can result in collapse and death within seconds to minutes.
[Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992. 698]**PEER REVIEWED**

The toxicologic differential diagnosis of cyanide poisoning includes methemoglobinemia ..., asphyxia ..., and poisonings ...
[Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992. 706]**PEER REVIEWED**

Hydrogen cyanide poisoning is marked by abrupt onset of profound toxic effects that may include syncope, seizures, coma gasping respirations, and cardiovascular collapse, causing death within minutes.
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1265]**PEER REVIEWED**

Acute cyanide poisoning is rapidly fatal. Less acute cases may produce symptoms such as headache, dizziness, nausea, and so on.
[Lunn, G., E.B. Sansone. Destruction of Hazardous Chemicals in the Laboratory. New York, NY: John Wiley & Sons, Inc. 1994. 133]**PEER REVIEWED**

Symptoms of acute cyanide poisoning are headache, giddiness, and a sense of sinking; palpitations; dyspnea with inadequate ventilation; and unconsciousness. When convulsions occur they are typically associated with brain hypoxia related to terminal respiratory arrest. Chronic manifestations of toxicity include skin disorders ... nasal irritation and drainage, headaches and neurologic problems such as tremor.
[Rom, W.N. (ed.). Environmental and Occupational Medicine. 2nd ed. Boston, MA: Little, Brown and Company, 1992. 545]**PEER REVIEWED**

Human Toxicity Values:

Lethal adult dose of hydrogen cyanide is 50 mg.
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1477]**PEER REVIEWED**

Skin, Eye and Respiratory Irritations:

Hydrogen cyanide is a mild upper respiratory irritant and may cause slight irritation of the nose and throat. There may also be irritation from skin and eye contact with the liquid.
[Sittig, M. Handbook of Toxic and Hazardous Chemicals and Carcinogens, 1985. 2nd ed. Park Ridge, NJ: Noyes Data Corporation, 1985. 508]**PEER REVIEWED**

Medical Surveillance:

Pre-placement and periodic examinations should include the cardiovascular and central nervous systems, liver and kidney function, blood, history of fainting and dizzy spells. Blood cyanide levels may be useful during acute intoxication. Urinary thiocyanate levels have been used but are nonspecific and are elevated in smokers.
[Sittig, M. Handbook of Toxic and Hazardous Chemicals and Carcinogens, 1985. 2nd ed. Park Ridge, NJ: Noyes Data Corporation, 1985. 508]**PEER REVIEWED**

Initial medical examination /should include/: a complete history and physical examination ... to detect existing conditions that might place the exposed employee at incr risk & to establish a baseline for future health monitoring. ... Examination of cardiovascular, nervous, & upper resp systems, & thyroid should be stressed. The skin should be exam for evidence of chronic disorders. ... The aforementioned medical exam should be repeated on an annual basis. ... /Cyanides/
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) Publication No. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981.1]**PEER REVIEWED**

Arterial Blood Gases: Arterial blood gases may be useful for monitoring of metabolic acidosis that can occur from cyanide poisoning. /Cyanide/
[Ryan, R.P., C.E. Terry (eds.). Toxicology Desk Reference 4th ed. Volumes 1-3. Taylor & Francis, washington, D.C. 1997. 912]**PEER REVIEWED**

EKG Measurement: EKG monitoring may be useful since changes have been found with cyanide exposure. /Cyanide/
[Ryan, R.P., C.E. Terry (eds.). Toxicology Desk Reference 4th ed. Volumes 1-3. Taylor & Francis, washington, D.C. 1997. 912]**PEER REVIEWED**

The assessment of cyanide exposure can be accomplished through measurement of cyanide. Most information found in the literature regarding monitoring for absorption of cyanide preferred the measurement of blood cyanide. ... Blood Reference Ranges: Normal - non-smokers, <0.02 ug/ml; smokers, average 0.041 ug/ml; Exposed - Levels of <0.2 ug/ml have been found to be non-toxic; however, levels of 0.5 - 1.0 ug/ml have been associated with tachycardia and flushing. Toxic - Levels of 1.0 - 2.5 ug/ml have been associated with obtundation; coma and respiratory depression with levels greater than 2.5 ug/ml; death with values greater than 3 ug/ml. Serum or Plasma Reference Ranges: Normal - cyanide: nonsmoker, 0.004 ug/ml; smoker, 0.006 ug/ml; Exposed - not established; Toxic - cyanide; greater than 0.1 ug/ml. Urine Reference Ranges: Normal - not established; Exposed - not established; Toxic - not established. /Cyanide/
[Ryan, R.P., C.E. Terry (eds.). Toxicology Desk Reference 4th ed. Volumes 1-3. Taylor & Francis, washington, D.C. 1997. 911]**PEER REVIEWED**

Respiratory Symptom Questionnaires: Questionnaires have been published by the American Thoracic Society and the British Medical Research Council. These questionnaires have been found to be useful in identification of people with chronic bronchitis, however certain pulmonary function tests such as FEV1 have been found to be better predictors of chronic airflow obstruction. /Cyanide/
[Ryan, R.P., C.E. Terry (eds.). Toxicology Desk Reference 4th ed. Volumes 1-3. Taylor & Francis, washington, D.C. 1997. 913]**PEER REVIEWED**

Chest Radiography: This test is widely used for assessing pulmonary disease. Chest radiographs have been found to be useful for detection of early lung cancer in asymptomatic people, especially for detection of peripheral tumors such as adenocarcinomas. However, even though OSHA mandates this test for exposure to some toxicants such as asbestos, there are conflicting views on its efficacy in detection of pulmonary disease. /Cyanide/
[Ryan, R.P., C.E. Terry (eds.). Toxicology Desk Reference 4th ed. Volumes 1-3. Taylor & Francis, washington, D.C. 1997. 913]**PEER REVIEWED**

Pulmonary Function Tests: The tests that have been found to be practical for population monitoring include: Spirometry and expiratory flow-volume curves; Determination of lung volumes; Diffusing capacity for carbon monoxide; Single-breath nitrogen washout; Inhalation challenge tests; Serial measurements of peak expiratory flow; Exercise testing. /Cyanide/
[Ryan, R.P., C.E. Terry (eds.). Toxicology Desk Reference 4th ed. Volumes 1-3. Taylor & Francis, washington, D.C. 1997. 913]**PEER REVIEWED**

Evaluation of Peripheral Neuropathy: Nerve conduction study; Electromyography; Quantitative sensory testing; Thermography. /Cyanide/
[Ryan, R.P., C.E. Terry (eds.). Toxicology Desk Reference 4th ed. Volumes 1-3. Taylor & Francis, washington, D.C. 1997. 914]**PEER REVIEWED**

Evaluation of Central Nervous System Effects: Evaluation of CNS effects can be performed through neuropsychological assessment, which consists of a clinical interview and administration of standardized personality and neuropsychological tests. The areas that the neuropsychology test batteries focus on include the domains of memory and attention; visuoperceptual, visual scanning, visuospatial, and visual memory; and motor speed and reaction time. There is limited data on which components of the test batteries are best indicators of early CNS effects. /Cyanide/
[Ryan, R.P., C.E. Terry (eds.). Toxicology Desk Reference 4th ed. Volumes 1-3. Taylor & Francis, washington, D.C. 1997. 914]**PEER REVIEWED**

Evaluation of Cranial Neuropathies: Evaluation of cranial nerve damage, as evidenced by symptoms such as loss of balance, visual function, smell, taste, or sensation on the face, can be accomplished through a physical examination focusing on tests such as: Smell Assessment ... Visual Assessment ... Facial and Trigeminal Nerve Assessment ... Vestibular Assessment ... Hearing Assessment. /Cyanide/
[Ryan, R.P., C.E. Terry (eds.). Toxicology Desk Reference 4th ed. Volumes 1-3. Taylor & Francis, washington, D.C. 1997. 914]**PEER REVIEWED**

Populations at Special Risk:

... WORKERS WITH CHRONIC DISEASES OF KIDNEYS, RESPIRATORY TRACT, SKIN, OR THYROID ARE AT GREATER RISK OF DEVELOPING TOXIC CYANIDE EFFECTS THAN ARE HEALTHY WORKERS. /CYANIDES/
[International Labour Office. Encyclopedia of Occupational Health and Safety. Vols. I&II. Geneva, Switzerland: International Labour Office, 1983. 576]**PEER REVIEWED**

Probable Routes of Human Exposure:

Inhalation of vapor or aerosol, percutaneous absorption of liquid and concn vapor, ingestion and eye and skin contact.
[Sittig, M. Handbook of Toxic and Hazardous Chemicals and Carcinogens, 1985. 2nd ed. Park Ridge, NJ: Noyes Data Corporation, 1985. 508]**PEER REVIEWED**

... Hydrogen cyanide can be absorbed through the skin ...
[Hamilton, A., and H. L. Hardy. Industrial Toxicology. 3rd ed. Acton, Mass.: Publishing Sciences Group, Inc., 1974. 222]**PEER REVIEWED**

EXPOSURE ... OCCURS ... WITH FUMIGATION OF SHIPS, WORKSHOPS, & DWELLINGS ... IN FUMIGATION INTENDED TO KILL AGRICULTURAL PARASITES, IN CHEM LABORATORIES, IN BLAST-FURNACE GAS, IN MFR OF ILLUMINATING GAS, & IN GAS FROM BURNING NITROCELLULOSE. INDUST PROCESSES ... WITH ... DANGER OF HCN ... EXPOSURE ARE PREPN OF CYANIDES & DECOMP OF CYANIDES BY EXPOSURE TO AIR & BY WEAK ACIDS & EXTRACTION OF PHOSPHORIC ACID FROM BONES. PRESENCE OF HCN IN VARIOUS INDUST GASES RESULTS FROM INCOMPLETE COMBUSTION OF NITROGEN-CONTAINING ORG CMPD ...
[Hamilton, A., and H. L. Hardy. Industrial Toxicology. 3rd ed. Acton, Mass.: Publishing Sciences Group, Inc., 1974. 221]**PEER REVIEWED**

HYDROGEN CYANIDE AIR CONTENTS IN THE WORKPLACE WITH PROTECTION MEASURES FOR BRIQUETTING OF FERROSILICON ARE 0.5-5.0 PPM. THE URINARY THIOCYANATES CONTENT IN EXPOSED WORKERS IS GIVEN.
[CREMOSNIK-PAJIC P ET AL; PRO INT CONGR OCCUP HEALTH, 19TH 2 (PHYS HAZARDS, DUSTS VAP, OCCUP HYG): 1069-74 (1980)]**PEER REVIEWED**

Occupational diseases caused by exposure to the asphyxiants carbon monoxide, hydrogen cyanide, or hydrogen sulfide were reveiwed. Exposure to hydrogen cyanide may occur involved in the chemical maufacture of monomers.
[World Health Organization; Early Detection of Occupational Diseases 154-164 (1986)]**PEER REVIEWED**

Some common furnishing fabrics and padding materials that give rise to smoke and acutely toxic substances on combustion were subjected to chemical and biological testing. Materials were cotton, cotton-rayon, rayon, wool, poly(vinyl alc)-poly(vinyl chloride), modacrylic, polyurethane foam, polyester wadding, and neoprene foam. The products were selected for the type of fire-resistant finishes used. Samples were heated at 500 and 700 degrees C in air, in accordance with the procedures of DIN 53446. Hydrogen cyanide was detected in the smoke gases. The changes in composition of the smoke gases with time and heavy components in the smoke were examined qualitatively. Particulates and liquids in the smoke were trapped in an ice trap for analysis. The toxicity of the smoke and smoke gases to rats was also measured. The carbon monoxide binding in rat blood was detected via carboxyhemoglobin measurement. Frequently, the fireproofing additives gave rise to a higher heat of combustion, but even at lower heats the smoke contained toxic gases. ... In a room lethal amounts of hydrogen cyanide are formed from modacrylics and Flamentin-flameproof cotton at the lower temp and from wool at the higher temp.
[Kallonen R et al; Tutkimuksia-Valt Tek Tutkimuskeskus 278: 56 (1984)]**PEER REVIEWED**

The toxicology of gases, vapors, mists, and fumes which workers may be exposed to in an occupational setting are reviewed. Included are the asphyxiant gases carbon dioxide, nitrogen, methane, carbon monoxide, hydrogen cyanide, and hydrogen sulfide, and the irritant gases ammonia, chlorine, ozone, phosgene, sulfur dioxide, and oxides of nitrogen. Industries whose workers may be at at risk of being exposed to these agents are numerous. They include various industries involving chemical refining, welding, mining, degreasing, electoplating, bleaching, sewage treatment industries.
[Seaton A, Morgan WKC; Occupational Lung Diseases 2: 609-42 (1988)]**PEER REVIEWED**

NIOSH (NOES Survey 1981-1983) has statistically estimated that 3,780 workers (254 of these are female) are potentially exposed to hydrogen cyanide in the US(1). Occupational exposure to hydrogen cyanide may occur through inhalation and dermal contact with this compound at workplaces where hydrogen cyanide is produced or used(SRC). The general population may be exposed to hydrogen cyanide from automobile exhaust and waste incinerators(SRC).
[(1) NIOSH; National Occupational Exposure Survey (NOES) (1983)]**PEER REVIEWED**

Body Burden:

Hydrogen cyanide is present in human being's blood(1). People who smoke or consume vegetables having a relatively high hydrogen cyanide content may have slightly higher blood levels(1).
[(1) Pesce LD; Kirk-Othmer Encycl Chem Technol 4th ed. Kroschwitz JI, ed. NY, NY: John Wiley and Sons 7: 758-82 (1993)]**PEER REVIEWED**

Minimum Fatal Dose Level:

The lethal oral dose of HCN is estimated to be about 50 milligrams in an adult.
[Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992. 704]**PEER REVIEWED**

Emergency Medical Treatment:

Emergency Medical Treatment:

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The following Overview, *** HYDROGEN CYANIDE ***, is relevant for this HSDB record chemical.

Life Support:
   o   This overview assumes that basic life support measures
       have been instituted.
Clinical Effects:
  0.2.1 SUMMARY OF EXPOSURE
   0.2.1.1 ACUTE EXPOSURE
     A)  Coma, tonic-clonic seizures, palpitations, dilated
         pupils, hyperventilation, hypoventilation, shock,
         cyanosis, severe metabolic acidosis, initial
         tachycardia and hypertension followed by bradycardia
         and hypotension, and respiratory arrest may be seen in
         serious poisonings. Noncardiogenic pulmonary edema and
         a wide variety of cardiac conduction defects and
         arrhythmias may develop. Nausea and vomiting may be
         noted.
     B)  Percutaneous absorption may occur, but is usually seen
         only with total-body liquid exposure or immersion.
         Dermal absorption of significant amounts of hydrogen
         cyanide gas has not been reported in humans.
  0.2.4 HEENT
   0.2.4.1 ACUTE EXPOSURE
     A)  Dilated pupils are common in severe poisoning. Retinal
         arteries and veins that appear equally red on
         funduscopic examination suggest the diagnosis. Corneal
         edema may be seen. A burning sensation in the mouth and
         throat may occur.
   0.2.4.2 CHRONIC EXPOSURE
     A)  Transient blindness can occur, although it rarely does.
         Auditory disturbances are occasionally present in
         chronic poisoning.
  0.2.5 CARDIOVASCULAR
   0.2.5.1 ACUTE EXPOSURE
     A)  Tachycardia and hypertension may be seen in the initial
         phases of cyanide poisoning. Bradycardia and
         hypotension are seen in the late phases of cyanide
         poisoning. EKG changes and ST-T segment elevation or
         depression may also be seen.
  0.2.6 RESPIRATORY
   0.2.6.1 ACUTE EXPOSURE
     A)  Respiratory tract irritation, hyperpnea, tachypnea,
         hypoventilation, apnea, noncardiogenic pulmonary edema
         and cyanosis may develop at various times after
         exposure.
   0.2.6.2 CHRONIC EXPOSURE
     A)  Upper respiratory tract irritation has been reported
         after chronic occupational exposure.
  0.2.7 NEUROLOGIC
   0.2.7.1 ACUTE EXPOSURE
     A)  Headache may be an early sign of cyanide poisoning. CNS
         stimulation with varied presentations may be seen in
         the early stages of cyanide poisoning. Coma and
         seizures are common in severe cyanide poisoning. In one
         case paralysis occurred, and parkinsonian syndromes
         have been observed. Rare cases of neurological sequelae
         have been reported.
   0.2.7.2 CHRONIC EXPOSURE
     A)  Symptoms reported after chronic exposure include
         vertigo, tremors, weakness, dizziness, mental
         confusion, motor aphasia, slurred speech, permanent
         mental and motor impairment, hemiparesis, seizures and
         progressive mental deterioration.
  0.2.8 GASTROINTESTINAL
   0.2.8.1 ACUTE EXPOSURE
     A)  Nausea, vomiting and abdominal pain may occur after
         ingestion of cyanide salts.
   0.2.8.2 CHRONIC EXPOSURE
     A)  Nausea, vomiting and violent or recurring abdominal
         pain may occur.
  0.2.11 ACID-BASE
   0.2.11.1 ACUTE EXPOSURE
     A)  Increased anion gap metabolic acidosis and serum
         lactate levels are common.
  0.2.13 HEMATOLOGIC
   0.2.13.1 ACUTE EXPOSURE
     A)  Cherry-red venous blood may occur and is due to the
         inability of tissue to remove oxygen from the blood.
   0.2.13.2 CHRONIC EXPOSURE
     A)  Anemia may be present in a well-developed case of
         chronic poisoning.
  0.2.14 DERMATOLOGIC
   0.2.14.1 ACUTE EXPOSURE
     A)  Cyanide has been said to be absorbed through intact
         skin.
   0.2.14.2 CHRONIC EXPOSURE
     A)  Dermal irritation has been reported after chronic
         exposure.
  0.2.15 MUSCULOSKELETAL
   0.2.15.2 CHRONIC EXPOSURE
     A)  Lassitude and easy fatigue are usually present.
  0.2.16 ENDOCRINE
   0.2.16.1 ACUTE EXPOSURE
     A)  Insulin resistance was noted in a severely
         cyanide-poisoned patient.
  0.2.18 PSYCHIATRIC
   0.2.18.1 ACUTE EXPOSURE
     A)  Irrational and violent behavior and manic episodes
         occurred in a patient after inhalation exposure.
  0.2.20 REPRODUCTIVE HAZARDS
    A)  At the time of this review, no reproductive studies were
        found for hydrogen cyanide in humans.
    B)  In laboratory animals, related cyanide compounds did
        cause resorptions, malformations and teratogenic effects
        in offspring.
  0.2.21 CARCINOGENICITY
   0.2.21.1 IARC CATEGORY
     A)  IARC Carcinogenicity Ratings for CAS74-90-8 (IARC,
         2004):
      1)  Not Listed
   0.2.21.2 HUMAN OVERVIEW
     A)  At the time of this review, no studies were found on
         the potential carcinogenic activity of hydrogen cyanide
         in humans.
   0.2.21.3 ANIMAL OVERVIEW
     A)  At the time of this review, no studies were found on
         the potential carcinogenic activity of hydrogen cyanide
         in laboratory animals.
  0.2.22 GENOTOXICITY
    A)  At the time of this review, no data were available to
        assess the mutagenic or genotoxic potential of this
        agent.
Laboratory:
   A)  If respiratory tract irritation or respiratory depression
       is evident, monitor arterial blood gases, chest x-ray,
       and pulmonary function tests.
   B)  Determine hemoglobin, arterial blood gases, venous pO2 or
       measured venous percent oxygen saturation, electrolytes,
       serum lactate and whole-blood cyanide levels.
   C)  MRI studies may be useful in identifying the location and
       extent of brain injury in patients with cyanide-induced
       parkinsonian syndrome.
Treatment Overview:
  0.4.2 ORAL EXPOSURE
    A)  Perform gastric lavage with a large-bore tube after
        endotracheal intubation. DO NOT INDUCE EMESIS with syrup
        of ipecac.
     1)  ACTIVATED CHARCOAL: Administer charcoal as a slurry
         (240 mL water/30 g charcoal). Usual dose: 25 to 100 g
         in adults/adolescents, 25 to 50 g in children (1 to 12
         years), and 1 g/kg in infants less than 1 year old.
     2)  GASTRIC LAVAGE: Consider after ingestion of a
         potentially life-threatening amount of poison if it can
         be performed soon after ingestion (generally within 1
         hour). Protect airway by placement in Trendelenburg and
         left lateral decubitus position or by endotracheal
         intubation. Control any seizures first.
      a)  CONTRAINDICATIONS: Loss of airway protective reflexes
          or decreased level of consciousness in unintubated
          patients; following ingestion of corrosives;
          hydrocarbons (high aspiration potential); patients at
          risk of hemorrhage or gastrointestinal perforation;
          and trivial or non-toxic ingestion.
    B)  Administer 100 percent oxygen - establish secure
        large-bore IV.
    C)  Prepare the cyanide antidote kit for use in symptomatic
        patients.
     1)  AMYL NITRITE AMPULE - Inhale ampule contents for 30
         seconds every minute until sodium nitrite is
         administered. Use a new ampule every three minutes.
     2)  SODIUM NITRITE - Administer IV (ADULT-10 mL over
         absolutely no less than 5 minutes; CHILD (with normal
         hemoglobin concentration) - 0.12 to 0.33 mL/kg up to 10
         mL). Repeat one-half of initial sodium nitrite dose 30
         minutes later if there is inadequate clinical response.
         Monitor blood pressure frequently. Reduce nitrite
         administration rate if hypotension occurs.
     3)  SODIUM THIOSULFATE - Administer IV immediately
         following sodium nitrite (ADULT: 50 mL of 25 percent
         solution; CHILD: 1.65 mL/kg of 25 percent solution).
         Repeat one-half of initial sodium thiosulfate dose 30
         minutes later if there is inadequate clinical response.
    D)  SODIUM BICARBONATE - Administer one mEq/kg IV to
        acidotic patients.
    E)  SEIZURES: Administer a benzodiazepine IV; DIAZEPAM
        (ADULT: 5 to 10 mg, repeat every 10 to 15 min as needed.
        CHILD: 0.2 to 0.5 mg/kg, repeat every 5 min as needed)
        or LORAZEPAM (ADULT: 2 to 4 mg; CHILD: 0.05 to 0.1
        mg/kg).
     1)  Consider phenobarbital if seizures recur after diazepam
         30 mg (adults) or 10 mg (children > 5 years).
     2)  Monitor for hypotension, dysrhythmias, respiratory
         depression, and need for endotracheal intubation.
         Evaluate for hypoglycemia, electrolyte disturbances,
         hypoxia.
    F)  METHEMOGLOBINEMIA -
     1)  Rarely, clinically significant excessive
         methemoglobinemia has occurred after sodium nitrite
         therapy. Some authors have suggested that methylene
         blue should not be used in this setting, because it
         could cause the release of cyanide from the
         cyanmethemoglobin complex. Such authors have suggested
         that emergency exchange transfusion is the treatment of
         choice.
     2)  Hyperbaric oxygen therapy could be used to support the
         patient while preparations for exchange transfusion are
         being made.
     3)  However, methylene blue has been used successfully in
         this setting without worsening the clinical course. As
         long as intensive-care monitoring and further antidote
         doses, if required, are available, methylene blue can
         most likely be safely administered in this setting.
     4)  METHEMOGLOBINEMIA: Administer 1 to 2 mg/kg of 1%
         methylene blue slowly IV in symptomatic patients.
         Additional doses may be required.
    G)  HYPERBARIC OXYGEN may also be useful in severe cases not
        responsive to other therapy.
    H)  ACUTE LUNG INJURY: Maintain ventilation and oxygenation
        and evaluate with frequent arterial blood gas or pulse
        oximetry monitoring. Early use of PEEP and mechanical
        ventilation may be needed.
    I)  HYPOTENSION: Infuse 10 to 20 mL/kg isotonic fluid. If
        hypotension persists, administer dopamine (5 to 20
        mcg/kg/min) or norepinephrine (ADULT: begin infusion at
        0.5 to 1 mcg/min; CHILD: begin infusion at 0.1
        mcg/kg/min); titrate to desired response.
    J)  HEMODIALYSIS and HEMOPERFUSION do not seem to be
        indicated or efficacious in most cases of cyanide
        poisoning.
    K)  ALTERNATIVE ANTIDOTES - Kelocyanor(R) (dicobalt-EDTA),
        hydroxocobalamin and 4-DMAP (4-dimethylaminophenol) are
        alternative cyanide antidotes in clinical use in various
        countries outside the USA. See TREATMENT SECTION in the
        main body of this document for more information.
  0.4.3 INHALATION EXPOSURE
    A)  INHALATION: Move patient to fresh air. Monitor for
        respiratory distress. If cough or difficulty breathing
        develops, evaluate for respiratory tract irritation,
        bronchitis, or pneumonitis. Administer oxygen and assist
        ventilation as required. Treat bronchospasm with inhaled
        beta2 agonist and oral or parenteral corticosteroids.
    B)  Administer 100 percent oxygen - establish secure
        large-bore IV.
    C)  Prepare the cyanide antidote kit for use in symptomatic
        patients.
     1)  AMYL NITRITE AMPULE - Inhale ampule contents for 30
         seconds every minute until sodium nitrite is
         administered. Use a new ampule every three minutes.
     2)  SODIUM NITRITE - Administer IV (ADULT-10 mL over
         absolutely no less than 5 minutes; CHILD (with normal
         hemoglobin concentration) - 0.12 to 0.33 mL/kg up to 10
         mL). Repeat one-half of initial sodium nitrite dose 30
         minutes later if there is inadequate clinical response.
         Monitor blood pressure frequently. Reduce nitrite
         administration rate if hypotension occurs.
     3)  SODIUM THIOSULFATE - Administer IV immediately after
         sodium nitrite (ADULT: 50 mL of 25 percent solution;
         CHILD: 1.65 mL/kg of 25 percent solution). Repeat
         one-half of initial sodium thiosulfate dose 30 minutes
         later if there is inadequate clinical response.
    D)  SODIUM BICARBONATE - Administer one mEq/kg IV to
        acidotic patients.
    E)  SEIZURES: Administer a benzodiazepine IV; DIAZEPAM
        (ADULT: 5 to 10 mg, repeat every 10 to 15 min as needed.
        CHILD: 0.2 to 0.5 mg/kg, repeat every 5 min as needed)
        or LORAZEPAM (ADULT: 2 to 4 mg; CHILD: 0.05 to 0.1
        mg/kg).
     1)  Consider phenobarbital if seizures recur after diazepam
         30 mg (adults) or 10 mg (children > 5 years).
     2)  Monitor for hypotension, dysrhythmias, respiratory
         depression, and need for endotracheal intubation.
         Evaluate for hypoglycemia, electrolyte disturbances,
         hypoxia.
    F)  METHEMOGLOBINEMIA
     1)  Rarely, clinically significant excessive
         methemoglobinemia has occurred after sodium nitrite
         therapy. Some authors have suggested that methylene
         blue should not be used in this setting, because it
         could cause the release of cyanide from the
         cyanmethemoglobin complex. Such authors have suggested
         that emergency exchange transfusion is the treatment of
         choice.
     2)  Hyperbaric oxygen therapy could be used to support the
         patient while preparations for exchange transfusion are
         being made.
     3)  However, methylene blue has been used successfully in
         this setting without worsening the clinical course. As
         long as intensive-care monitoring and further antidote
         doses, if required, are available, methylene blue can
         most likely be safely administered in this setting.
     4)  METHEMOGLOBINEMIA: Administer 1 to 2 mg/kg of 1%
         methylene blue slowly IV in symptomatic patients.
         Additional doses may be required.
    G)  HYPERBARIC OXYGEN may also be useful in severe cases not
        responsive to supportive and antidotal therapy.
    H)  ACUTE LUNG INJURY: Maintain ventilation and oxygenation
        and evaluate with frequent arterial blood gas or pulse
        oximetry monitoring. Early use of PEEP and mechanical
        ventilation may be needed.
    I)  HYPOTENSION: Infuse 10 to 20 mL/kg isotonic fluid. If
        hypotension persists, administer dopamine (5 to 20
        mcg/kg/min) or norepinephrine (ADULT: begin infusion at
        0.5 to 1 mcg/min; CHILD: begin infusion at 0.1
        mcg/kg/min); titrate to desired response.
    J)  ALTERNATIVE ANTIDOTES - Kelocyanor(R) (dicobalt-EDTA),
        hydroxocobalamin and 4-DMAP (4-dimethylaminophenol) are
        alternative cyanide antidotes in clinical use in various
        countries outside the US. See TREATMENT SECTION in the
        main body of this document for more information.
  0.4.4 EYE EXPOSURE
    A)  DECONTAMINATION: Irrigate exposed eyes with copious
        amounts of room temperature water for at least 15
        minutes. If irritation, pain, swelling, lacrimation, or
        photophobia persist, the patient should be seen in a
        health care facility.
    B)  Laboratory animals have developed serious systemic
        cyanide poisoning after ocular exposure. Human poisoning
        cases have not been reported due to eye exposure only.
        If systemic cyanide poisoning is suspected after eye
        exposure, REFER to TREATMENT RECOMMENDATIONS in the
        INHALATION EXPOSURE section above.
  0.4.5 DERMAL EXPOSURE
    A)  OVERVIEW
     1)  DECONTAMINATION: Remove contaminated clothing and wash
         exposed area thoroughly with soap and water. A
         physician may need to examine the area if irritation or
         pain persists.
     2)  Although cyanide can be absorbed through intact skin,
         most reported cases have involved whole-body immersion
         in cyanide solutions or large-area burns with molten
         cyanide solutions. Most nitrile compounds are well
         absorbed through intact skin, and may cause delayed
         onset of symptoms after exposure by this route.
     3)  Treatment should include recommendations listed in the
         INHALATION EXPOSURE section when appropriate.
Range of Toxicity:
   A)  The average fatal adult dose of hydrogen cyanide is 50 to
       60 mg. Exposure to airborne concentrations of 90 ppm or
       greater for 30 minutes or more may be incompatible with
       life. Death may result from a few minutes of exposure to
       300 ppm.

[Rumack BH POISINDEX(R) Information System Micromedex, Inc., Englewood, CO, 2004; CCIS Volume 122, edition expires Nov, 2004. Hall AH & Rumack BH (Eds): TOMES(R) Information System Micromedex, Inc., Englewood, CO, 2004; CCIS Volume 122, edition expires Nov, 2004.]**PEER REVIEWED**

Antidote and Emergency Treatment:

Basic Treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 l/min. Administer amyl nitrite ampules as per protocol and physician order ... . Monitor for shock and treat if necessary ... . Monitor for pulmonary edema and treat if ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . /Cyanide and related compounds/
[Bronstein, A.C., P.L. Currance; Emergency Care for Hazardous Materials Exposure. 2nd ed. St. Louis, MO. Mosby Lifeline. 1994.,p. 387-8]**PEER REVIEWED**

Advanced Treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious or in respiratory arrest. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Start an IV with D5W /SRP: "To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. Administer cyanide antidote kit as per protocol and physician order ... . Monitor and treat cardiac arrhythmias if necessary ... . Consider vasopressors to treat hypotension without signs of hypovolemia ... . Consider drug therapy for pulmonary edema ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Cyanide and related compounds/
[Bronstein, A.C., P.L. Currance; Emergency Care for Hazardous Materials Exposure. 2nd ed. St. Louis, MO. Mosby Lifeline. 1994. 388]**PEER REVIEWED**

Although a variety of agents are effective antidotes in the experimental animal (nitrites, dimethylaminophenol, cobalt EDTA, hydroxocobalamin, stroma-free methemoglobin solutions, pyruvate, thiosulfate, sulfur sulfanes, mercaptopyruvate, oxygen) only the three-step Eli-Lilly cyanide kit is approved in the US. /Cyanide/
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1481]**PEER REVIEWED**

... The two main antidotal strategies ... are the induction of methemoglobinemia with amyl nitrite or sodium nitrite and the enhancement of conversion of cyanide to thiocyanate by the administration of sodium thiosulfate.
[Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992. 706]**PEER REVIEWED**

/SRP: For patients treated with nitrites:/ Measurement of methemoglobin may be useful for assessing exposure. However, methemoglobin levels may be artificially low if not analyzed within a few hours after drawing the blood. Methemoglobin levels have been found to correlate with clinical symptoms in most cases. /Cyanide/
[Ryan, R.P., C.E. Terry (eds.). Toxicology Desk Reference 4th ed. Volumes 1-3. Taylor & Francis, washington, D.C. 1997. 912]**PEER REVIEWED**

The use of the combination consisting of 4 g of hydroxoycobalamin and 8 g of sodium thiosulfate as an antidote in cases of cyanide poisoning is reviewed. The antidote, which has been used in France since 1970, has proved to be nontoxic and therefore can be given in cases where the diagnosis of cyanide poisoning is not absolutely certain. On the other hand, the Lilly Cyanide Antidote Kit, which has been approved for use in the USA for the same purpose, has been shown to be toxic and its use requires caution. The antidotal effectiveness of the association of hydroxoycobalamin and sodium thiosulfate has been demonstrated in mice and other animal species poisoned with cyanide. Most animal studies reveal a strong antidotal synergism between the two agents. In France, the efficacy of the antidotal combination has been proved in patients who have ingested as much as 1.5 g of potassium cyanide and have blood cyanide levels on the order of 15 ug/ml. In the USA, the antidotal combination is designated as an orphan drug by the FDA and studies have been started to validate its safety and efficacy before being approved for use in this country. /Cyanide/
[Hall AH, Rumack BH; J Emer Med 5 (2): 115-21 (1987)]**PEER REVIEWED**

Animal Toxicity Studies:

Non-Human Toxicity Excerpts:

IN EXPTL ANIMALS, DEMONSTRATION OF EFFECTS OF CYANIDE POISONING ON RETINA & OPTIC NERVE HAS BEEN SUCCESSFUL PRINCIPALLY WITH ACUTE SEVERE, NEAR-LETHAL OR LETHAL POISONINGS. /CYANIDES/
[Grant, W. M. Toxicology of the Eye. 2nd ed. Springfield, Illinois: Charles C. Thomas, 1974. 334]**PEER REVIEWED**

IN RABBITS, AFTER SUBLETHAL DOSES OF CYANIDE, CHANGES IN ELECTRORETINOGRAM HAVE BEEN OBSERVED. /CYANIDE/
[Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986. 287]**PEER REVIEWED**

... IF ... ANIMALS ... HAVE EATEN CYANOGENIC PLANTS, CLINICAL SIGNS MAY VARY FROM MILD TACHYPNEA & APPARENT ANXIETY TO SEVERE PANTING, GASPING, & BEHAVIORAL ALARM. OTHER SIGNS INCL SALIVATION, MUSCLE TREMORS, LACRIMATION, URINATION & DEFECATION, SEVERE COLIC, EMESIS, PROSTRATION ... CLONIC CONVULSIONS, MYDRIASIS, & RAPID DEATH. ... MUCOUS MEMBRANES ARE ... PINK & BLOOD IS CHERRY RED & MAY NOT CLOT. RED COLOR IS DUE TO HYPEROXYGENATION THAT OCCURS WHILE THE ANIMAL IS DYING. THERE MAY BE AGONAL HEMORRHAGES ON HEART. GI TRACT & LUNGS MAY HAVE CONGESTION & PETECHIAL HEMORRHAGES. /CYANOGENIC PLANTS/
[Booth, N.H., L.E. McDonald (eds.). Veterinary Pharmacology and Therapeutics. 5th ed. Ames, Iowa: Iowa State University Press, 1982. 961]**PEER REVIEWED**

Acute systemic toxicity of hydrogen cyanide, sodium cyanide, and potassium cyanide by instillation into the inferior conjunctival sac was investigated in rabbits. LD50 value of HCN was 0.039 mmol/kg. Signs of toxicity appeared rapidly & death occurred within 3 to 12 min after instillation of hydrogen cyanide into the conjunctival sac of the rabbit. Thus, following ocular instillation, cyanides may be absorbed across the conjunctival blood vessels in amounts sufficient to produce systemic toxicity.
[Ballantyne B; J Toxicol, Cutaneous Ocul Toxicol 2 (2-3): 119-29 (1983)]**PEER REVIEWED**

Effects of sublethal hydrogen cyanide exposure on exogenous yolk production by liver was examined in sexually maturing female rainbow trout at onset of vitellogenesis. Fish were exposed to 0.01, 0.02 & 0.03 mg/l for 7 days at 12.5 deg C. Serum calcium & phosphoprotein phosphorus levels were measured & hepatosomatic indexes calculated as indicators of exogenous yolk production. Serum calcium levels were reduced at 0.01 mg/l in males & females. There was no apparent effect upon serum phosphoprotein phosphorus levels or hepatosomatic indexes at this concn. Serum calcium levels in females were reduced & hepatosomatic indexes declined at 0.02 mg/l. The implication of reduced serum calcium during early vitellogenesis upon secondary yolk production & reproduction in females is discussed.
[Da Costa H, Ruby SM; Arch Environ Contam Toxicol 13 (1): 101-4 (1984)]**PEER REVIEWED**

There is an apparent relation between the degree of swimming inhibition caused by cyanide and temperature, the effect being more pronounced at lower temperatures. For example, /rainbow trout in a Blawzka type swimming chamber exhibited the following measurements/, at 45 ug/l hydrogen cyanide and 18 deg C, swimming performance was reduced by about 26% but at 30 ug/l and 12 deg C this reduction was 71%. At 15 ug/l and 6 deg C the trout suffered a 90% reduction of swimming stamina. The effects of cyanide on swimming are immediate and may last long after the fish have been returned to clean water. Even though immediate improvement of swimming after return of the fish to cyanide free water occurs, full recovery of chronically exposed salmonoids is not complete 15-20 days after their removal from cyanide containing water.
[Nat'l Research Council Canada; The Effects of Cyanides on Aquatic Organisms with Emphasis Upon Fresh Water Fishes p.97 (1976) NRCC No.19246]**PEER REVIEWED**

No reproduction occurred among adult bluegills when exposed for 289 days to 5.2 ug of hydrogen cyanide/l. During this period, however, only a total of 13 spawnings occurred in two controls and no dose response relationship was observed.
[Kimball G et al; Trans Am Fish Soc 107: 341 (1978) as cited in USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-5 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Except for the more sensitive invertebrate species, such as Daphnia pulex and Gammarus pseudolimnaeus, invertebrate species are usually more tolerant of cyanide than are freshwater fish species, which have most acute values clustered between 50 to 200 ug/l. A long-term survival and two life cycle test with fish gave chronic values of 7.9, 14 and 16 ug/l, respectively, with Gammarus pseudolimnaeus being comparable to fish in sensitivity and isopods being considerably more tolerant. /Free cyanide: HCN and CN-/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-6 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Toxicologic evaluation of smoke produced during smoldering chair tests was undertaken by exposing mice to smoke emitted prior to, as well as following, flaming ignition of the chairs. By exposing several groups of mice to undiluted smoke from the room containing the chairs, as well as various dilutions of the smoke, different levels of acute lethality were obtained. Chairs constructed with polyurethane foam were found to create higher toxic atmospheres than chairs constructed with polyester or cotton fiber cushions. ... Sensory irritation monitored in mice during the smoldering tests indicated that an intense level of irritation was present long before large amounts of smoke were generated and long before flaming ignition occurred. The phenomenon of eye, nose and throat irritation would, therefore, be the first effect impeding escape attempts of individuals in a fire situation. Sensory irritation was followed by asphyxiation as evolution of carbon monoxide or hydrogen cyanide, or both, occurred.
[Alarie Y et al; Fundam Appl Toxicol 3 (6): 619-26 (1983)]**PEER REVIEWED**

It is suspected that hydrogen cyanide may be an important factor in incapacitating fire victims, but the effects of sublethal exposures are not well characterized. Also, the incapacitating effects of fire atmospheres result from exposure to a mixture of toxic products so that the contribution from each component is difficult to determine. The mechanisms of incapacitation in monkeys exposed to the pyrolysis products of polyacrylonitrile were compared to those resulting from low level hydrogen cyanide gas exposures. The physiological effects of the polyacrylonitrile atmospheres were almost identical to those of hydrogen cyanide gas alone. They consisted of hyperventilation, followed by loss of consciousness after 1-5 min, bradycardia with arrhythmias and T-wave abnormalities, and were followed by a rapid recovery after exposure. Hydrogen cyanide is considered to be the major toxic product formed by the pyrolysis of polycrylonitrile. It is suggested that hydrogen cyanide may produce rapid incapacitation at low blood levels of cyanide in fires.
[Purser DA et al; Arch Environ Health 39 (6): 394-400 (1984)]**PEER REVIEWED**

PHYTOTOXIC BUT USUALLY NOT AT VAPOR CONCN FATAL TO INSECTS; AVOID USE ON TREES BEARING COPPER SPRAY RESIDUES OR TREATED FOR CORRECTION OF COPPER DEFICIENCY.
[Spencer, E. Y. Guide to the Chemicals Used in Crop Protection. 7th ed. Publication 1093. Research Institute, Agriculture Canada, Ottawa, Canada: Information Canada, 1982. 329]**PEER REVIEWED**

Some common furnishing fabrics and padding materials that give rise to smoke and acutely toxic substances on combustion were subjected to chemical and biological testing. Materials were cotton, cotton-rayon, rayon, wool, poly(vinyl alc)-poly(vinyl chloride), modacrylic, polyurethane foam, polyester wadding, and neoprene foam. The products were selected for the type of fire-resistant finishes used. Samples were heated at 500 and 700 degrees C in air, in accordance with the procedures of DIN 53446. Hydrogen cyanide was detected in the smoke gases. The changes in composition of the smoke gases with time and heavy components in the smoke were examined qualitatively. Particulates and liquids in the smoke were trapped in an ice trap for analysis. The toxicity of the smoke and smoke gases to rats was also measured. The carbon monoxide binding in rat blood was detected via carboxyhemoglobin measurement. Frequently, the fireproofing additives gave rise to a higher heat of combustion, but even at lower heats the smoke contained toxic gases. ... In a room lethal amounts of hydrogen cyanide are formed from modacrylics and Flamentin-flameproof cotton at the lower temp and from wool at the higher temp.
[Kallonen R et al; Tutkimuksia-Valt Tek Tutkimuskeskus 278: 56 (1984)]**PEER REVIEWED**

IN THE CASE OF HYDROCYANIC ACID AND CYANIDES /IN VERY HIGH DOSES/, DEATH USUALLY OCCURS /IN ANIMALS/ WITHIN FEW SECONDS: THERE MAY BE CONVULSIONS, PARALYSIS, STUPOR, & CESSATION OF RESPIRATION BEFORE THAT OF HEARTBEATS. /CYANIDES/
[Clarke, M. L., D. G. Harvey and D. J. Humphreys. Veterinary Toxicology. 2nd ed. London: Bailliere Tindall, 1981. 176]**PEER REVIEWED**

Male and female mice and rats were subjected in an exposure chamber (30 cu m) to the products of thermal degradation of polyurethane foam, linen, or acrylics, and the concentrations of toxic gases (CO, CO2, HCN, and NOx) were determined and their single and combined effects were related to mortality rate. Death of the animals was observed after 30 minute exposure to these toxic gases and the dead animals showed epithelial and pulmonary lesions, acute lung edema, and the presence of C-rich particles in the lung. Mice were more sensitive to these toxic gases than rats. These gases were not toxic to the liver or kidney following 15 days exposure.
[Girard-Wallon C et al; Ann Falsif Expert Chim Toxicol 76 (818): 207-25 (1983)]**PEER REVIEWED**

Toxicity of combustion products from ... polyurethane foam was examined in mice at 25 deg and at 19 vol % oxygen, and in a medium with higher temp (35 deg C and 45 deg C) and reduced oxygen level (16% and 11%). The exposure was for 30 min. ... polyurethane foam toxic effects were especially noticeable at 35 deg C and 16% oxygen level. The toxic effect of polyurethane foam also increased with increasing temp and reduced oxygen content.
[Ilichkin VS et al; Gig Sanit (9): 82-84 (1985)]**PEER REVIEWED**

Chemical composition and the toxicity (rats) of the airborne combustion products (500-700 deg C) of certain Finish textiles and upholstery materials, which were either treated with fire retardants or untreated, were investigated. ... Relatively high concentrations of HCN (>100 ppm) were generated from modacrylic, wool, Flamentin (fire retardant; a mixture or ammonium salts) treated cotton, etc. ... Most of deaths in rats occurred during the 30 min exposure. At 500 deg C, the most toxic materials were modacrylic, Flamentin-cotton and polyester fiber retardant fiber fill. At 700 deg C, modacrylic, wool, Flamentin-cotton, had the strongest toxic effects, in decreasing order. Toxic effects were attributed to HCN and carbon monoxide. No toxic effect was linked to hydrogen chloride despite ... high concentrations.
[Kallonen R et al; J Fire Sci 3 (3): 145-60 (1985)]**PEER REVIEWED**

Combustion of a polyamide fiberglass for 5 min at air flow rates of 0.5, 1, or 2 l/min, generated 5.34, 3.25 and 0.122 mg HCN/l respectively. Carbon monoxide content also decreased with increasing air rate. ... A 5 min inhalation of combustion gases evolving at 0.5 l air/min, killed 50% of mice, whereas the offgases evolving at 1-2 l/min were nonlethal. Exposure to gases evolved at 0.5-2 l air/min during 1-, 2-, or 3- min combustion induced a 48.7, 32.3, and 19.2%, respectively, transformation of Hb into COHb.
[Kustov VV et al; Gig Sanit (9): 79-81 (1983)]**PEER REVIEWED**

A series of experiments were performed in mice to evaluate the toxicity of carbon monoxide, hydrogen cyanide (HCN) and low oxide atm. The results for both carbon monoxide and HCN for the time concn relationships to produce asphyxiation and death indicate that the asphyxiation end-point did not offer advantages over the measurement of acute lethality. Percentage escape activity measurement for carbon monoxide was not a good measure since it occurred just prior to asphyxiation or death. Depression of central nervous system (CNS), measured by depression of resp rate, occurred at concentrations lower than the LC50 by about a factor of 3. Such an effect can be detected at even lower concentrations, & unlike asphyxiation or disappearance of escape activity, this effect is not followed immediately by death which was generally the case with other 2 endpoints. At low concentrations of oxygen, just above concn which caused death, a very small decrease in resp rate followed by recovery was observed; with both carbon monoxide and HCN, however, a severe resp depression was observed at concentrations below those inducing death and while recovery was fairly rapid with HCN, it was very slow with carbon monoxide.
[Matijak-Schaper M, Alarie Y; J Combust Toxicol 9 (Feb): 21-61 (1982)]**PEER REVIEWED**

Groups of adult rats were repeatedly exposed to the pyrolysis products either of a rigid polyurethane foam or of hemlock, to which was added 0 or 200 ppm hydrogen cyanide (HCN) under conditions that did not result in depletion of oxygen in the exposure atmosphere. Other groups were exposed to HCN in air or in air + carbon monoxide Some of the HCN exposed groups were presented with a chlorpromazine/thiosulfate combination protective against cyanide toxicity. Exposure to HCN without protective pretreatment was associated with mild cardiotoxicity as measured by the magnitude of release of cardiac-specific creatine phosphokinase activity and by the number of ectopic heart beats induced by norepinephrine injection. Much of the difference in the cardiotoxicities of polyurethane and hemlock smokes could be related to their different contents of HCN. However, the prevalence of focal histopathological lesions in the rat hearts did not correlate well with the other 2 measures of cardiotoxicity.
[O'Flaherty EJ, Thomas WC; Toxicol Appl Pharmacol 63 (3): 373-81 (1982)]**PEER REVIEWED**

Carbon monoxide, hydrogen cyanide (HCN), and hydrochloric acid are the major gaseous toxicants encountered in the atmosphere during fires. Experimental intoxications increased protein content in lavage pulmonary fluid indicating pulmonary subedema or edema. Expected for hydrochloric acid this occurrence was not so predictable for HCN and carbon monoxide; ... The increase of neutral sugars, sialic acid, and fucose ... contents revealed the irritating effect of HCN and hydrochloric acid.
[Pre J et al; Arch Mal Prof Med Trav Secur Soc 45 (3): 159-64 (1984)]**PEER REVIEWED**

-o CYANIDES SUCH AS ... HYDROGEN CYANIDE, POTASSIUM CYANIDE AND SODIUM CYANIDE ARE S, INTERFERING WITH METABOLIC PROCESSES & CAUSING RAPID DEATH. RE POISONING, PUPILS ARE CHARACTERISTICALLY WIDELY DILATED.
[Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986. 287]**PEER REVIEWED**

The lethal toxicity (96 hr LC50) of cyanide (HCN) to juvenile rainbow trout (Salmo gairdneri) varied seasonally and with exercise (swimming at one body length/sec). The trout were acclimated to the 12 deg C test temperature for 3-4 weeks, under a 12 hr photoperiod before being tested at different times of the year. In summer, there was no significant difference of sensitivity between exercised and non exercised trout. From summer to winter, the 96 hr LC50 for exercised trout remained unchanged at 0.052 mg/l HCN, while the LC50 of the non-exercised trout dropped significantly to 0.043 mg/l HCN. The median survival times of the two groups of trout were the same in the summer, but in the winter the exercised fish survived twice as long as the non-exercised fish.
[McGeachy SM, Leduc G; Arch Environ Contam Toxicol 17 (3): 313-18 (1988)]**PEER REVIEWED**

Larval fathead minnows (Pimephales promelas) were exposed for 96 hr to several concentrations of hydrogen cyanide. The range of safe concentrations determined from 96 hr macromolecular content (RNA, DNA & protein) & growth was within or near the range of safe concentrations determined by concomitant longer term exposure. RNA, DNA & protein content/larva & RNA/DNA ratio were sensitive to toxicant stress & followed a log-linear dose response. Larval RNA content appeared to be at the 96 hr measurement most responsive to toxicant exposure.
[Barron MG, Adelman IR; Can J Fish Aquat Sci 41 (1): 141-50 (1984)]**PEER REVIEWED**

Growth of fathead minnow yolk sac larvae was characterized from changes in dry weight and total content and concentrations of RNA, DNA and protein in fish exposed to a sublethal level of HCN (hydrogen cyanide) (58 ug/l) and in age matched controls. Cyanide toxicosis occurred within 24 hr of exposure as evidenced by significant reductions in protein and RNA content and RNA/DNA ratio of larvae. After 96 hr exposure to HCN, larvae exhibited the same growth rate and protein synthetic rate (RNA/DNA) as control fish. HCN toxicosis and recovery is rapid and at least partial tolerance to HCN develops within 96 hr of exposure in larval fathead minnows.
[Barron MG, Adelman IR; Comp Biochem Physiol Comp Pharmacol Toxicol 81 (2): 341-44 (1985)]**PEER REVIEWED**

Cyanide markedly affected growth and resting metabolic rate while causing degenerative hepatic necrosis in juvenile rainbow trout (Salmo gairdneri). ... In continuously renewed water at 12.5 deg C, fish were exposed to cyanide concn of 0.00, 0.01, 0.02, or 0.03 mg/l hydrogen cyanide (HCN) for 18 days. At 0.02 and 0.03 mg/l HCN, growth was reduced by 40 to 95% after 18 days. At all concn, cyanide caused a severe initial repression of specific growth rate, followed by a highly significant increase which was insufficient to compensate for the original repression. Previous exposure to cyanide promoted a higher resting metabolic rate during the six days following exposure, the effect increasing with cyanide concn. At all concn tested, widespread cyanide-induced degenerative necrosis of hepatocytes was observed.
[Dixon DG, Leduc G; Arch Environ Contam Toxicol 10: 117-31 (1981)]**PEER REVIEWED**

Non-Human Toxicity Values:

LC50 Rat inhalation 142 ppm/30 min
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Mouse inhalation 169 ppm/30 min
[The Merck Index. 10th ed. Rahway, New Jersey: Merck Co., Inc., 1983. 696]**PEER REVIEWED**

LC50 Dog inhalation 300 ppm/3 min
[The Merck Index. 10th ed. Rahway, New Jersey: Merck Co., Inc., 1983. 696]**PEER REVIEWED**

LD50 Rat subcutaneous 3700 ug/kg
[ITII. Toxic and Hazarous Industrial Chemicals Safety Manual. Tokyo, Japan: The International Technical Information Institute, 1982. 273]**PEER REVIEWED**

LCLo Rabbit inhalation 600 mg/cu m/2 min
[ITII. Toxic and Hazarous Industrial Chemicals Safety Manual. Tokyo, Japan: The International Technical Information Institute, 1982. 274]**PEER REVIEWED**

LDLo Groundhog subcutaneous 100 ug/kg
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1838]**PEER REVIEWED**

LD50 Rabbit im 486 ug/kg
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1838]**PEER REVIEWED**

LD50 Rabbit ocular routes 1040 ug/kg
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1838]**PEER REVIEWED**

LD50 Rat iv 810 ug/kg
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1838]**PEER REVIEWED**

LD50 Mouse oral 3700 ug/kg
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1838]**PEER REVIEWED**

LD50 Mouse ip 2990 ug/kg
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1838]**PEER REVIEWED**

LD50 Mouse iv 990 ug/kg
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1838]**PEER REVIEWED**

LD50 Mouse im 2700 ug/kg
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1838]**PEER REVIEWED**

LD50 Dog iv 1340 ug/kg
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1838]**PEER REVIEWED**

Ecotoxicity Values:

Daphnia: 50% immobilization after 48 hr at 1.8 mg/l. /Conditions of bioassay not specified/
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Asellus communis 2.29 mg/l/96 hr /Conditions of bioassay not specified/
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Gammarus pseudolimnaeous 0.17 mg/l/96 hr /Conditions of bioassay not specified/
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

TLm Pinperch 0.069 mg/l/24 hr /Conditions of bioassay not specified/
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

TLm Lepomis humilis (sunfish) 0.18 mg/l/24 hr /Conditions of bioassay not specified/
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

TLm Pinperch 0.05 mg/l/24 hr (in seawater) /Conditions of bioassay not specified/
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LTC Lepomis macrochirus (bluegill eggs) 535-693 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Lepomis macrochirus (bluegill swim up fry) 232-365 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Lepomis macrochirus (bluegill, juvenile) 75-125 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Perca flavescens (yellow perch eggs) >276-389 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Perca flavescens (yellow perch, juvenile) 76-108 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Salvelinus fontinalis (brook trout eggs) >212 to >242 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Salvelinus fontinalis (brook trout, sac fry) 108-518 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Salvelinus fontinalis (brook trout, swim up fry) 56-106 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Salvelinus fontinalis (brook trout, juvenile) 53-143 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Salmo gairdnerii (rainbow trout) 57 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Pimephales promelas (fathead minnow eggs) 121-352 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Pimephales promelas (fathead minnow, swim up fry) 82-122 ug/l/hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Pimephales promelas (fathead minnow, juvenile) 82-137 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Pimephales promelas (fathead minnow, juvenile, wild stock) 157-191 ug/l/96 hr, flow-through bioassay
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 742]**PEER REVIEWED**

LC50 Goniobasis livescens (snail) 760,000 ug/l/48 hr /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-20 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Lymnaea emarginata (snail) 3,300 ug/l/48 hr /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-20 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Lymnaea sp, (snail, embryo) 51,900 ug/l/96 hr
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-20 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Physa integra (snail) 1,350 ug/l/48 hr /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-20 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Stemonema rubrum (mayfly) 500 ug/l/48 hr /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-20 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Hyfropsyche sp (caddisfly) 2,000 ug/l/48 hr /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-20 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Salmo gairdneri (rainbow trout) 68 ug/l/48 hr /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-21 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Pimephales promelas (fathead minnow) 240 ug/l/48 hr /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-23 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Pimephales promelas (fathead minnow, juvenile) 120 ug/l/5 days /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-23 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Pimephales promelas (fathead minnow, juvenile) 123 ug/l/96 hr /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-24 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Lepomis macrochirus (bluegill, juvenile) 134 ug/l/48 hr /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-25 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Lepomis macrochirus (bluegill, juvenile) 154 ug/l/72 hr /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-25 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Lepomis macrochirus (bluegill) 160 ug/l/48 hr /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-25 (1980) EPA 440/5-80-037]**PEER REVIEWED**

LC50 Perca flavescens (yellow perch, embryo) 281 ug/l/96 hr /Conditions of bioassay not specified/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.B-26 (1980) EPA 440/5-80-037]**PEER REVIEWED**

TSCA Test Submissions:

Hydrocyanic acid (CAS # 74-90-8) was evaluated for subacute inhalation toxicity in Sprague-Dawley rats (5/sex/group) administered whole-body exposures to a mean analytical concentration of 67.8 +/- 7.0 ppm for 6 hours on 3 consecutive days under dynamic conditions (2060-2200 L/min). An initial exposure was associated with hypoactivity, rapid shallow breathing, anoxia/hypoxia signs, and convulsions, followed by chromorhinorrhea, convulsions and varied signs of labored breathing. Survivors of 2 exposures exhibited rapid breathing and reduced mean bodyweight with a solitary male rat exhibiting arching of the back. Signs of toxicity associated with a third exposure were limited to hypoactivity and quick shallow breathing; mean daily bodyweight gains were restored. Mortality occurred either during or following an initial exposure in 1 and 2 males, respectively. Necropsy of these study decedents revealed cyanosis of the extremities, hemorrhagic lungs, lung and tracheal edema, blanching of the liver, chromorhinorrhea, urine-filled bladder, gaseous distention of the gastro-intestinal tract, and a solitary incidence of blood engorgement of the heart and surrounding vasculature. On terminal necropsy of study survivors, females exhibited slight to moderate hemorrhage (3/5) and grey discoloration (2/5) of the lung.
[Monsanto Co; Inhalation Pilot Study of Hydrogen Cyanide Exposure in Sprague-Dawley Rats; 05/16/83; EPA Document # 88-920007543; Fiche No. OTS0545731]**UNREVIEWED**

Metabolism/Pharmacokinetics:

Metabolism/Metabolites:

LARGER PORTION /OF ABSORBED CYANIDE/ ... IS CONVERTED BY ... SULFURTRANSFERASE/S/ TO ... THIOCYANATE ION. ... MINOR METABOLIC PATHWAYS INCL COMBINATION WITH CYSTINE TO FORM 2-IMINO-THIAZOLIDINE-4-CARBOXYLIC ACID, OXIDATION TO CARBON DIOXIDE & FORMATE, & CONVERSION TO CYANOCOBALAMIN.
[Goodman, L.S., and A. Gilman. (eds.) The Pharmacological Basis of Therapeutics. 5th ed. New York: Macmillan Publishing Co., Inc., 1975. 904]**PEER REVIEWED**

The enzymatic decomposition of thiocyanate into cyanide by a thiocyanate oxidase has been found in mammals, but only in erythrocytes.
[Nat'l Research Council Canada; The Effects of Cyanides on Aquatic Organisms With Emphasis Upon Fresh Water Fishes p.61 (1976) NRCC No.19246]**PEER REVIEWED**

A very small fraction of the total cyanide is bound by hydroxocobalamin, probably less than 1 percent.
[Brink NG et al; Science 112: 354 (1950) as cited in USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-14 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Because the liver contains the highest activity of rhodanese, it is possible that existing liver disease might slow the rate of cyanide metabolism.
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-14 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Cyanide is converted to products which enter metabolic pathways for one-carbon compounds and is converted to formate and to carbon dioxide.
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-14 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Hydrogen cyanide reacts with acetaldehyde followed by hydrolysis to produce lactic acid
[CHEMICAL PRODUCTS SYNOPSIS: Hydrogen Cyanide, 1983]**PEER REVIEWED**

... CYANIDE ION IS CONJUGATED WITH SULFUR TO FORM THIOCYANATE. ... CONJUGATION IS CATALYZED BY ... RHODANESE WHICH IS WIDELY DISTRIBUTED IN MOST ANIMAL TISSUES ... /LIVER/ PARTICULARLY ACTIVE. ... RHODANESE MECHANISM IS CAPABLE OF DETOXICATING ONLY LIMITED AMT OF CYANIDE, SUCH AS ARE FORMED DURING NORMAL METAB. /ANOTHER SULFUR DONOR IS 3-MERCAPTOPYRUVATE. THE ENZYME, MERCAPTOSULFUR TRANSFERASE IS LOCALIZED IN CYTOSOL./ /CYANIDE/
[Parke, D. V. The Biochemistry of Foreign Compounds. Oxford: Pergamon Press, 1968. 96]**PEER REVIEWED**

Nitroprusside releases cyanide in vivo, and cyanide toxicity is a true complication of its use.
[Arnold WP et al; Anesthesiology 61 (3): 245-60 (1984)]**PEER REVIEWED**

/ONE OF/ THE MAJOR MECHANISM/S/ FOR REMOVING CYANIDE FROM THE BODY IS ITS ENZYMATIC CONVERSION, BY THE MITOCHONDRIAL ENZYME RHODANESE (TRANSSULFURASE), TO THIOCYANATE, WHICH IS RELATIVELY ... /LESS TOXIC/. /CYANIDE/
[Gilman, A.G., L.S.Goodman, and A. Gilman. (eds.). Goodman and Gilman's The Pharmacological Basis of Therapeutics. 7th ed. New York: Macmillan Publishing Co., Inc., 1985. 1643]**PEER REVIEWED**

RUMINANTS ARE MORE SUSCEPTIBLE TO POISONING BY CYANOGENIC PLANTS /SRP: WHICH RELEASE HYDROGEN CYANIDE/ THAN ARE HORSES & PIGS ... /CYANOGENIC PLANTS/
[Clarke, M. L., D. G. Harvey and D. J. Humphreys. Veterinary Toxicology. 2nd ed. London: Bailliere Tindall, 1981. 176]**PEER REVIEWED**

FACTORS THAT INCR LIKELIHOOD OF HCN POISONING FROM INGESTION OF CYANOGENIC PLANTS INCLUDE: (1) LARGE AMT OF FREE HCN & CYANOGENIC GLYCOSIDE IN PLANT, (2) RAPID INGESTION; (3) INGESTION OF A LARGE AMT OF PLANT, & (4) RUMINAL PH & MICROFLORA THAT CONTINUE TO HYDROLYZE GLYCOSIDE /SRP: TO RELEASE HYDROGEN CYANIDE/. RAPID INTAKE OF PLANT ... EQUIV TO ABOUT 4 MG HCN/KG OF BODY WT IS CONSIDERED TO BE LETHAL AMOUNT OF PLANT MATERIAL. ... /CYANOGENIC PLANTS/
[Booth, N.H., L.E. McDonald (eds.). Veterinary Pharmacology and Therapeutics. 5th ed. Ames, Iowa: Iowa State University Press, 1982. 961]**PEER REVIEWED**

Aliphatic nitriles have been postulated to manifest their toxicity through cyanide (CN) liberation. The signs of toxicity and effect of equitoxic LD50 doses of saturated and unsaturated aliphatic mono- and dinitriles on tissue and blood CN levels, tissue glutathione levels and cytochrome c oxidase activities were studied in rats. Signs of toxicity were classified into cholinomimetic effects observed with unsaturated nitriles and CNS effects observed with saturated potassium cyanide. Hepatic and blood CN levels 1 hr after treatment were highest following malononitrile and decreased in the order of propionitrile > potassium cyanide > butyronitrile > acrylonitrile > allylcyanide > fumaronitrile > acetonitrile. The order differed in brain where potassium cyanide preceded malononitrile and PCN. Hepatic and cytochrome c oxidase were significantly inhibited and corresponded to their CN levels. No significant inhibition of cytochrome c oxidase was observed in vitro. Acrylonitrile was the only nitrile which significantly reduced tissue GSH levels. Toxic expression of aliphatic nitriles depended on CN release and their degree of unsaturation. With unsaturated aliphatic nitriles CN release played a minimal role in their toxicity. /Cyanides/
[Ahmed AE, Farooqui M YH; Toxicol Lett (AMST) 12 (2-3): 157-64 (1982)]**PEER REVIEWED**

Acute toxicity and metabolism of 7 dinitriles in mice was studied in relation to the chemical structures. The oral LD50 for each nitrile was detected under different conditions for mice pretreated with either carbon tetrachloride (CCl4) or olive oil. All test nitriles were metabolized into cyanide in vivo and in vitro. The cyanide level was variable among the compounds (0.35-0.74 ug cyanide/g brain) at death in the brains of mice, the level from malononitrile and adiponitrile being comparable to that found in mice killed by dosing with potassium cyanide. After receiving each nitrile, the mean survival time of mice pretreated with CCl4 was prolonged and their brain cyanide level decreased when compared with the corresponding control. With malononitrile, the former did not significantly change and the latter decreased slightly. Brain cyanide levels of control mice at death showed a peak at the lower log P region, whereas those of CCl4 pretreated animals remained lower independently of log P, with the exception of malononitrile. Microsomal metabolism of nitriles to cyanide was greatly inhibited when microsomes were prepared from livers of mice pretreated with CCl4. The relationship between log (1/LD50-CCl4), LD50 in mice pretreated with CCl4, and log P fits a parabolic plot. /Cyanides/
[Tanii H et al; Arch Toxicol 57 (2): 88-93 (1985)]**PEER REVIEWED**

Humans detoxify cyanide by transferring sulfane sulfur to cyanide, thus converting it to thiocyanate (SCN). Thiocyanate is excreted in the urine ... Two main enzymes ... rhodanese ... and ... beta-mercaptopyruvate-cyanide sulfurtransferase.
[Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992. 701]**PEER REVIEWED**

Cyanide is rapidly taken up and sequestered by red blood cells. Such action does not appear to enhance the metabolism of cyanide, but might act to partially lessen toxicity by preventing the diffusion of cyanide out of blood into tissues.
[Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992. 702]**PEER REVIEWED**

Absorption, Distribution & Excretion:

IN 30 DAYS, 72% OF (14)C FROM IP DOSE OF (14)C-CYANIDE TO MICE WAS EXCRETED IN URINE & FECES, 25% IN EXPIRED AIR, & 3% WAS RETAINED ... PEAK EXCRETION OCCURRED WITHIN 10 MIN IN EXPIRED AIR & WITHIN 6-24 HR IN URINE & FECES.
[The Chemical Society. Foreign Compound Metabolism in Mammals. Volume 1: A Review of the Literature Published Between 1960 and 1969. London: The Chemical Society, 1970. 94]**PEER REVIEWED**

THE CYANIDE ION IS READILY ABSORBED AFTER ORAL OR PARENTERAL ADMIN. PROLONGED LOCAL CONTACT WITH ... HCN MAY RESULT IN ABSORPTION OF TOXIC AMT THROUGH SKIN. PART OF ABSORBED CYANIDE IS EXCRETED UNCHANGED BY THE LUNG. LARGER PORTION ... CONVERTED BY ... SULFURTRANSFERASE TO RELATIVELY NONTOXIC THIOCYANATE ION. /CYANIDE/
[Goodman, L.S., and A. Gilman. (eds.) The Pharmacological Basis of Therapeutics. 5th ed. New York: Macmillan Publishing Co., Inc., 1975. 904]**PEER REVIEWED**

Hydrogen cyanide vapor is absorbed rapidly through the lung. Because HCN has a pKa of 9.2 and exists primarily as the acid under biological conditions, absorption across the alveolar membrane should be rapid. Human inhalation of 270 ppm HCN vapor brings death immediately, while 135 ppm is fatal after 30 minutes.
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-7 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Hydrogen cyanide, in either liquid or vapor form, is absorbed through the skin. Absorption is probably increased if the skin is cut, abraded, or moist.
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-8 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Cyanide is distributed to all organs and tissues via the blood, where its concn in red cells is greater than that in plasma by a factor of two or three. Presumably, the accumulation of cyanide in erythrocytes is a reflection of its binding to methemoglobin. /Cyanides/
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-9 (1980) EPA 440/5-80-037]**PEER REVIEWED**

A significant difference between the amount of cyanide in the whole blood of smokers and non-smokers could not be detected, but, the plasma thiocyanate levels of the smokers were significantly elevated. A ratio of cyanide to thiocyanate in body fluids was about 1 to 1000. A more reliable index of cyanide exposure may be measurement of plasma thiocyanate rather than determination of whole blood cyanide.
[Pettigrew AR, Fell GS; Clin Chem 19: 466-71 (1973) as cited in NIOSH; Criteria Document: Hydrogen Cyanide and Cyanide Salts p.48 (1976) DHEW Pub. NIOSH 77-108]**PEER REVIEWED**

The acute systemic toxicity of hydrogen cyanide, sodium cyanide and potassium cyanide by instillation into the inferior conjunctival sac was investigated. In the rabbit, the LD50 values in mmol/kg were 0.039 for HCN, 0.103 for sodium cyanide, and 0.121 for potassium cyanide. The acute lethal toxicity of sodium cyanide was not significantly different when applied as a solution or solid, and mixing the solid with an inert powder (kaolin) did not modify the toxicity. For all preparations, signs of toxicity appeared rapidly and death occurred within 3 to 12 min of the eye being contaminated. Cyanide concns in blood, serum, and various tissues were measured, and the results found compatible with a diagnosis of death from acute cyanide poisoning. Thus, following their instillation into the conjunctival sac, cyanides may be absorbed across conjunctival blood vessels in amounts sufficient to produce systemic toxicity. Contamination of the eye with cyanide could be a hazardous route of exposure.
[Ballantyne B; J Toxicol, Cutaneous Ocul Toxicol 2 (2-3): 119-29 (1983)]**PEER REVIEWED**

Hydrogen cyanide (HCN) was significantly more toxic than sodium cyanide or potassium cyanide by im and transocular routes, and potassium cyanide significantly less toxic than HCN or sodium cyanide by skin penetration. Acute inhalation studies indicated a proportionately longer time to cause death at the lower concn, and thus larger total doses of HCN are required to cause death by low-concn than by high-concn exposure. Following death by acute cyanide poisoning, whole blood concn are high and diagnostic significance; serum levels are 1/3-1/2 those in whole blood. Blood cyanide concn vary with the route, being lowest by inhalation and skin penetration. For a given exposure route, blood concn are similar for different species. Cyanide concn in certain specific tissues vary markedly with exposure route.
[Ballantyne B; Dev Toxicol Environ Sci 11 (Dev Sci Pract Toxicol): 583-86 (1983)]**PEER REVIEWED**

CN- FORMS COMPLEXES WITH A NUMBER OF OTHER CHEMICALS (EG IN TISSUES) & HAS STRONG AFFINITY FOR COBALT. /CYANIDE ION/
[Booth, N.H., L.E. McDonald (eds.). Veterinary Pharmacology and Therapeutics. 5th ed. Ames, Iowa: Iowa State University Press, 1982. 961]**PEER REVIEWED**

CYANIDES ARE RAPIDLY ABSORBED FROM SKIN & ALL MUCOSAL SURFACES & ARE MOST DANGEROUS WHEN INHALED, BECAUSE TOXIC AMT ARE ABSORBED THROUGH BRONCHIAL MUCOSA & ALVEOLI. /CYANIDES/
[Haddad, L.M. and Winchester, J.F. Clinical Management of Poisoning and Drug Overdosage. Philadelphia, PA: W.B. Saunders Co., 1983. 745]**PEER REVIEWED**

Once absorbed into the body, cyanide can form complexes with heavy metal ions. /Cyanide/
[NIOSH; Criteria Document: Hydrogen Cyanide and Cyanide Salts p.45 (1976) DHEW Pub. NIOSH 77-108]**PEER REVIEWED**

Liquid hydrogen cyanide ran over the bare hand of a worker wearing a fresh air respirator. Cyanide inhalation was prevented, but the worker collapsed into deep unconsciousness within five minutes, suggesting significant percutaneous absorption. /Liquid hydrogen cyanide/
[Potter AL; Br J Ind Med 7: 125 (1950) as cited in USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-8 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Cyanide is concentrated in red blood cells at a RBC/plasma ratio is 100/l. The volume of distribution of cyanide ion is approximately 1.5 l/kg. About 60% if CN- in plasma is protein bound. /Cyanide/
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1478]**PEER REVIEWED**

... Cyanide salts are absorbed rapidly from mucous membranes ...By inhalation ...
[Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992. 701]**PEER REVIEWED**

Substantial absorption can occur through intact skin if vapor concentration is high.
[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997. 1265]**PEER REVIEWED**

Biological Half-Life:

Half-life for the conversion of cyanide to thiocyanate from a non-lethal dose in man is between 20 min and 1 hr. /Cyanide/
[Feldstein M, Klendshoj NC; J Lab Chin Med 44: 166-70 (1954) as cited in NIOSH; Criteria Document: Hydrogen Cyanide and Cyanide Salts p.45 (1976) DHEW Pub. NIOSH 77-108]**PEER REVIEWED**

Mechanism of Action:

The acute mode of action of hydrogen cyanide is limited to binding those porphyrins that contain iron III, such as cytochrome oxidase, hyperoxidases, and methemoglobin.
[Nat'l Research Council Canada; The Effect of Cyanides on Aquatic Organisms with Emphasis Upon Fresh Water Fishes p.11 (1982) NRCC No.19246]**PEER REVIEWED**

The inhibition of cytochrome oxidase is noncompetitive and hence, is independent of the relative proportions of toxicant and substrate with which the enzyme reacts. Thus, the acute toxicity of cyanide will be determined almost completely by the concn of cyanide (in the mitochondrial matrix) surrounding the structure on which cytochrome oxidase is thought to be located (oxysomes of the mitochondrial cristae). Differences in sensitivity to cyanide may occur between different animal species, and many plant mitochondria contain electron transport chains which are insensitive to cyanide.
[Nat'l Research Council Canada; The Effect of Cyanides on Aquatic Organisms with Emphasis Upon Fresh Water Fishes p.58 (1982) NRCC No.19246]**PEER REVIEWED**

While the concn of cytochrome oxidase in fish mitochondria apparently does not vary with ambient temperature, the activity of the enzyme is greater in mitochondria from cold-associated individuals. Therefore, one would expect fish to be more sensitive to cyanide when acclimated to lower temperatures.
[Nat'l Research Council Canada; The Effect of Cyanides on Aquatic Organisms with Emphasis Upon Fresh Water Fishes p.58 (1982) NRCC No.19246]**PEER REVIEWED**

When cyanide stops the production of ATP associated with the electron transport chain, another metabolic pathway is activated and ATP is synthesized via the degradation of glucose to lactic acid, or an equivalent end product. Degradation of glucose, commonly referred to as glycolysis, does not utilize oxygen but does not produce sufficient ATP to sustain organisms that are relatively active.
[Nat'l Research Council Canada; The Effect of Cyanides on Aquatic Organisms with Emphasis Upon Fresh Water Fishes p.58 (1982) NRCC No.19246]**PEER REVIEWED**

The mitochondrial electron transport system may also be seriously disturbed by cyanide through the inhibition of succinate dehydrogenase, which is a nonheme flavin-containing iron-sulfur protein which passes electrons to the cytochrome system. The peculiarity of this enzyme is its sulfur linkages which are of the persulfide or sulfane type, favoring a "labile sulfur" condition that is essential for activity. Cyanide is a strong thiophile reacting with the "labile" sulfur thus breaking the persulfide bond.
[Nat'l Research Council Canada; The Effect of Cyanides on Aquatic Organisms with Emphasis Upon Fresh Water Fishes p.59 (1982) NRCC No.19246]**PEER REVIEWED**

Hydroperoxidases consist of two classes of enzymes, catalases and peroxidases, both of which utilize hydrogen peroxide as a substrate. The ferro-heme group is strongly inhibited by cyanide, although the physiological significance at sublethal levels remains obscure. ... One tissue that could be seriously affected by the inhibition of catalase by cyanide is the blood, where the formation of hydrogen dioxide would lead to the oxidation of hemoglobin Fe(2+) into methemoglobin Fe(3+), thus reducing the oxygen carrying capacity of the organism.
[Nat'l Research Council Canada; The Effect of Cyanides on Aquatic Organisms with Emphasis Upon Fresh Water Fishes p.59 (1982) NRCC No.19246]**PEER REVIEWED**

During chronic cyanide exposure the precursers of Vitamin B12 may react with cyanide, thereby reducing the amount of available Vitamin B12.
[Nat'l Research Council Canada; The Effect of Cyanides on Aquatic Organisms with Emphasis Upon Fresh Water Fishes p.60 (1982) NRCC No.19246]**PEER REVIEWED**

The cyanide ion produces acute anoxia of the central nervous system by inactivating the cytochrome oxidase enzyme system necessary for tissue respiration. Death in acute cases occurs within a few seconds.
[Clarke, M. L., D. G. Harvey and D. J. Humphreys. Veterinary Toxicology. 2nd ed. London: Bailliere Tindall, 1981. 175]**PEER REVIEWED**

CYANIDE HAS A VERY HIGH AFFINITY FOR IRON IN FERRIC STATE. WHEN ABSORBED IT REACTS READILY WITH ... IRON OF CYTOCHROME OXIDASE IN MITOCHONDRIA; CELLULAR RESPIRATION IS THUS INHIBITED & CYTOTOXIC HYPOXIA RESULTS. SINCE UTILIZATION OF OXYGEN IS BLOCKED, VENOUS BLOOD IS OXYGENATED AND IS ALMOST AS BRIGHT RED AS ARTERIAL BLOOD. RESPIRATION IS STIMULATED BECAUSE CHEMORECEPTIVE CELLS RESPOND AS THEY DO TO DECREASED OXYGEN. A TRANSIENT STAGE OF CNS STIMULATION WITH HYPERPNEA AND HEADACHE IS OBSERVED; FINALLY THERE ARE HYPOXIC CONVULSIONS AND DEATH DUE TO RESPIRATORY ARREST. /CYANIDE/
[Gilman, A.G., L.S.Goodman, and A. Gilman. (eds.). Goodman and Gilman's The Pharmacological Basis of Therapeutics. 7th ed. New York: Macmillan Publishing Co., Inc., 1985. 1642]**PEER REVIEWED**

SINGLE DOSES OF CYANIDE PRODUCE ALTERATIONS IN PATTERN OF BRAIN METABOLITES CONSISTENT WITH DECR IN OXIDATIVE METABOLISM & INCR IN GLYCOLYSIS. DECR IN BRAIN GAMMA-AMINOBUTYRIC ACID ... HAVE BEEN ASCRIBED TO CYANIDE INHIBITION OF GLUTAMIC ACID DECARBOXYLASE. /CYANIDE/
[Gosselin, R.E., R.P. Smith, H.C. Hodge. Clinical Toxicology of Commercial Products. 5th ed. Baltimore: Williams and Wilkins, 1984.,p. III-126]**PEER REVIEWED**

THE CORTICAL GRAY MATTER, HIPPOCAMPUS (H1), CORPORA STRIATA, & SUBSTANTIA NIGRA ARE COMMONLY AFFECTED /BY CYANIDE/. ... CYANIDE ALSO HAS PROPENSITY FOR DAMAGING WHITE MATTER, PARTICULARLY CORPUS CALLOSUM. CYANIDE INHIBITS CYTOCHROME OXIDASE & PRODUCES CYTOTOXIC ANOXIA, BUT ALSO CAUSES HYPOTENSION THROUGH ITS EFFECTS ON HEART. /CYANIDE/
[Doull, J., C.D.Klassen, and M.D. Amdur (eds.). Casarett and Doull's Toxicology. 3rd ed., New York: Macmillan Co., Inc., 1986. 372]**PEER REVIEWED**

The cyanide ion (CN-) ... has a strong affinity for cobalt. /Cyanide ion/
[Booth, N.H., L.E. McDonald (eds.). Veterinary Pharmacology and Therapeutics. 5th ed. Ames, Iowa: Iowa State University Press, 1982. 961]**PEER REVIEWED**

The objective was to ascertain whether cyanide shares the properties of methylene blue as a selective inhibitor of vascular smooth muscle relaxation elicited by agents that stimulate the formation of cyclic GMP. Experiments were performed with endothelium-intact rings prepared from bovine intrapulmonary artery. Methylene blue, a good inhibitor of soluble guanylate cyclase, antagonized both arterial relaxation and cyclic GMP accumulation in response to sodium nitroprusside, glyceryl trinitrate, S-nitroso-N-acetylpenicillamine and acetylcholine. In contrast, cyanide inhibited only the responses to sodium nitroprusside. ... Contractile responses to phenylephrine, potassium, and U46619 were potentiated by methylene blue but not by cyanide. Cyanide does not share the properties of methylene blue as an inhibitor of arterial relaxation elicited by vasodilators that stimulate cyclic GMP formation.
[Ignarro LJ et al; J Pharmacol Exp Thr 26 (1): 30-36 (1986)]**PEER REVIEWED**

/CYANIDE/ ... REACTS ... WITH TRIVALENT IRON OF CYTOCHROME OXIDASE IN MITOCHONDRIA TO FORM THE CYTOCHROME OXIDASE-CN COMPLEX ... THE CYTOCHROME-OXIDASE-CN COMPLEX IS DISSOCIABLE; THE MITOCHONDRIAL ENZYME SULFURTRANSFERASE ... MEDIATES TRANSFER OF SULFUR FROM THIOSULFATE TO CYANIDE ION. THUS, THIOCYANATE IS FORMED ... KINETIC STUDIES INDICATE THAT THE CLEAVAGE OF THE THIOSULFATE SULFUR-SULFUR BOND IS THE RATE-LIMITING STEP IN THIS REACTION. RELATIVELY MINOR PATHWAYS INCL COMBINATION WITH CYSTINE TO FORM 2-IMINO-THIAZOLIDINE-4-CARBOXYLIC ACID, OXIDATION TO CARBON DIOXIDE & FORMATE, & FORMATION OF CYANOCOBALAMIN. /CYANIDE/
[Gilman, A.G., L.S.Goodman, and A. Gilman. (eds.). Goodman and Gilman's The Pharmacological Basis of Therapeutics. 7th ed. New York: Macmillan Publishing Co., Inc., 1985. 1642]**PEER REVIEWED**

Interactions:

Previous reports indicated that prophylactic protection against cyanide intoxication in mice can be enhanced by administration of chlorpromazine when it is given with sodium thiosulfate. The mechanism of potentiation of sodium thiosulfate by chlorpromazine was studied alone and in combination with sodium nitrite. Although chlorpromazine was found to induce a hypothermic response, the mechanism of enhancement of the antagonism of cyanide by chlorpromazine does not correlate with the hypothermia produced. Various other possible mechanisms were investigated, such as rate of methemoglobin formation, enzymatic activity of rhodanese and cytochrome oxidase, and alpha-adrenergic blockade. The alpha-adrenergic blocking properties of chlorpromazine may provide a basis for its antidotal effect, since this protective effect can be reversed with an alpha-antagonist, methoxamine. /Cyanide/
[Kong A et al; Toxicol Appl Pharmacol 71 (3): 407-13 (1983)]**PEER REVIEWED**

Mathematical modeling methods for the intoxication of rats by carbon monoxide and hydrogen cyanide are extended to accommodate combined atmospheres of these fire gas toxicants. Predictions using the Fractional ED model for both incapacitation and lethality show no significant differences from animal bioassay data. Use of the model is suggested as a substitute for live animal testing for the toxicity of smoke produced from burning materials.
[Hartzell GE et al; J Fire Sci 3 (5): 330-42 (1985)]**PEER REVIEWED**

Acute toxicity at single and combined exposures of carbon monoxide and hydrogen cyanide (HCN) was studied on rats in terms of concentration-time product (ppm/min) necessary to kill animals (lethal concentration time). ... After exposure, blood sample was withdrawn from the right side of the heart. Carbon monoxide concentrations in the gas and blood were determined gas chromatographically. HCN in the gas sample was measured spectrophotometrically, after being absorbed into sodium hydroxide solution ... At single exposures, mean lethal concentration time for carbon monoxide was 78,000 + or - 22,000 and for HCN was 4,700 + or - 940. In combined exposure, various combinations of carbon monoxide and HCN were used. A fractional concentration time, defined as a ration of concentration time to lethal concentration time, multiplied by 100, was calculated for each gas. A linear relationship between fractional concentration times averaged 100 + or - 26. On the other hand, linear relation was not observed between blood levels of the two toxicants at death.
[Yamamoto K, Kuwahara C; Z Rechtsmed 86 (4): 287-94 (1981)]**PEER REVIEWED**

Cysteine, a sulfur-containing amino acid, is required to metabolize ascorbic acid (as ascorbate sulfate) and detoxify cyanide (to thiocyanate). In guinea pigs, conjoint use of laetrile (a cyanogenic glycoside) and ascorbic acid (in large doses) decreases the detoxification of cyanide derived from laetrile through diminishing the availability of cysteine, but not impairing hepatic rhodanese activity, which is involved in the detoxification of cyanide to thiocyanate.
[Basu TK; Can J Physiol Pharmacol 61 (11): 1426-30 (1983)]**PEER REVIEWED**

... Solids that can release a toxic gas on reacting with water ... chemicals are nonselective, highly reactive, and cytotoxic.
[Klaassen, C.D., M.O. Amdur, Doull J. (eds.). Casarett and Doull's Toxicology. The Basic Science of Poisons. 5th ed. New York, NY: McGraw-Hill, 1995. 679]**PEER REVIEWED**

Pharmacology:

Interactions:

Previous reports indicated that prophylactic protection against cyanide intoxication in mice can be enhanced by administration of chlorpromazine when it is given with sodium thiosulfate. The mechanism of potentiation of sodium thiosulfate by chlorpromazine was studied alone and in combination with sodium nitrite. Although chlorpromazine was found to induce a hypothermic response, the mechanism of enhancement of the antagonism of cyanide by chlorpromazine does not correlate with the hypothermia produced. Various other possible mechanisms were investigated, such as rate of methemoglobin formation, enzymatic activity of rhodanese and cytochrome oxidase, and alpha-adrenergic blockade. The alpha-adrenergic blocking properties of chlorpromazine may provide a basis for its antidotal effect, since this protective effect can be reversed with an alpha-antagonist, methoxamine. /Cyanide/
[Kong A et al; Toxicol Appl Pharmacol 71 (3): 407-13 (1983)]**PEER REVIEWED**

Mathematical modeling methods for the intoxication of rats by carbon monoxide and hydrogen cyanide are extended to accommodate combined atmospheres of these fire gas toxicants. Predictions using the Fractional ED model for both incapacitation and lethality show no significant differences from animal bioassay data. Use of the model is suggested as a substitute for live animal testing for the toxicity of smoke produced from burning materials.
[Hartzell GE et al; J Fire Sci 3 (5): 330-42 (1985)]**PEER REVIEWED**

Acute toxicity at single and combined exposures of carbon monoxide and hydrogen cyanide (HCN) was studied on rats in terms of concentration-time product (ppm/min) necessary to kill animals (lethal concentration time). ... After exposure, blood sample was withdrawn from the right side of the heart. Carbon monoxide concentrations in the gas and blood were determined gas chromatographically. HCN in the gas sample was measured spectrophotometrically, after being absorbed into sodium hydroxide solution ... At single exposures, mean lethal concentration time for carbon monoxide was 78,000 + or - 22,000 and for HCN was 4,700 + or - 940. In combined exposure, various combinations of carbon monoxide and HCN were used. A fractional concentration time, defined as a ration of concentration time to lethal concentration time, multiplied by 100, was calculated for each gas. A linear relationship between fractional concentration times averaged 100 + or - 26. On the other hand, linear relation was not observed between blood levels of the two toxicants at death.
[Yamamoto K, Kuwahara C; Z Rechtsmed 86 (4): 287-94 (1981)]**PEER REVIEWED**

Cysteine, a sulfur-containing amino acid, is required to metabolize ascorbic acid (as ascorbate sulfate) and detoxify cyanide (to thiocyanate). In guinea pigs, conjoint use of laetrile (a cyanogenic glycoside) and ascorbic acid (in large doses) decreases the detoxification of cyanide derived from laetrile through diminishing the availability of cysteine, but not impairing hepatic rhodanese activity, which is involved in the detoxification of cyanide to thiocyanate.
[Basu TK; Can J Physiol Pharmacol 61 (11): 1426-30 (1983)]**PEER REVIEWED**

... Solids that can release a toxic gas on reacting with water ... chemicals are nonselective, highly reactive, and cytotoxic.
[Klaassen, C.D., M.O. Amdur, Doull J. (eds.). Casarett and Doull's Toxicology. The Basic Science of Poisons. 5th ed. New York, NY: McGraw-Hill, 1995. 679]**PEER REVIEWED**

Minimum Fatal Dose Level:

The lethal oral dose of HCN is estimated to be about 50 milligrams in an adult.
[Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992. 704]**PEER REVIEWED**

Environmental Fate & Exposure:

Environmental Fate/Exposure Summary:

Hydrogen cyanide's production and use as a starting material in the manufacture of acrylates, cyanide salts, herbicides and dyes as well as its former use as a fumigant resulted in its release to the environment through various waste streams. If released to air, a vapor pressure of 742 mm Hg at 25 deg C indicates hydrogen cyanide will exist solely as a vapor in the ambient atmosphere. Vapor-phase hydrogen cyanide will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 535 days. If released to soil, hydrogen cyanide is expected to have very high mobility. Volatilization from moist soil surfaces is expected to be an important fate process based upon a Henry's Law constant of 1.33X10-4 atm-cu m/mole. Hydrogen cyanide may volatilize from dry soil surfaces based upon its vapor pressure. Hydrogen cyanide can be biodegraded by acclimated microbial cultures and sludges, but is usually toxic at high concentrations to unacclimated microbial systems. If released into water, hydrogen cyanide is not expected to adsorb to suspended solids and sediment in water. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 3 hours and 3 days, respectively. A pKa of 9.2 indicates that the dissociated form may exist at high pH. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Occupational exposure to hydrogen cyanide may occur through inhalation and dermal contact with this compound at workplaces where hydrogen cyanide is produced or used. The general population may be exposed to hydrogen cyanide from automobile exhaust and waste incinerators. (SRC)
**PEER REVIEWED**

Probable Routes of Human Exposure:

Inhalation of vapor or aerosol, percutaneous absorption of liquid and concn vapor, ingestion and eye and skin contact.
[Sittig, M. Handbook of Toxic and Hazardous Chemicals and Carcinogens, 1985. 2nd ed. Park Ridge, NJ: Noyes Data Corporation, 1985. 508]**PEER REVIEWED**

... Hydrogen cyanide can be absorbed through the skin ...
[Hamilton, A., and H. L. Hardy. Industrial Toxicology. 3rd ed. Acton, Mass.: Publishing Sciences Group, Inc., 1974. 222]**PEER REVIEWED**

EXPOSURE ... OCCURS ... WITH FUMIGATION OF SHIPS, WORKSHOPS, & DWELLINGS ... IN FUMIGATION INTENDED TO KILL AGRICULTURAL PARASITES, IN CHEM LABORATORIES, IN BLAST-FURNACE GAS, IN MFR OF ILLUMINATING GAS, & IN GAS FROM BURNING NITROCELLULOSE. INDUST PROCESSES ... WITH ... DANGER OF HCN ... EXPOSURE ARE PREPN OF CYANIDES & DECOMP OF CYANIDES BY EXPOSURE TO AIR & BY WEAK ACIDS & EXTRACTION OF PHOSPHORIC ACID FROM BONES. PRESENCE OF HCN IN VARIOUS INDUST GASES RESULTS FROM INCOMPLETE COMBUSTION OF NITROGEN-CONTAINING ORG CMPD ...
[Hamilton, A., and H. L. Hardy. Industrial Toxicology. 3rd ed. Acton, Mass.: Publishing Sciences Group, Inc., 1974. 221]**PEER REVIEWED**

HYDROGEN CYANIDE AIR CONTENTS IN THE WORKPLACE WITH PROTECTION MEASURES FOR BRIQUETTING OF FERROSILICON ARE 0.5-5.0 PPM. THE URINARY THIOCYANATES CONTENT IN EXPOSED WORKERS IS GIVEN.
[CREMOSNIK-PAJIC P ET AL; PRO INT CONGR OCCUP HEALTH, 19TH 2 (PHYS HAZARDS, DUSTS VAP, OCCUP HYG): 1069-74 (1980)]**PEER REVIEWED**

Occupational diseases caused by exposure to the asphyxiants carbon monoxide, hydrogen cyanide, or hydrogen sulfide were reveiwed. Exposure to hydrogen cyanide may occur involved in the chemical maufacture of monomers.
[World Health Organization; Early Detection of Occupational Diseases 154-164 (1986)]**PEER REVIEWED**

Some common furnishing fabrics and padding materials that give rise to smoke and acutely toxic substances on combustion were subjected to chemical and biological testing. Materials were cotton, cotton-rayon, rayon, wool, poly(vinyl alc)-poly(vinyl chloride), modacrylic, polyurethane foam, polyester wadding, and neoprene foam. The products were selected for the type of fire-resistant finishes used. Samples were heated at 500 and 700 degrees C in air, in accordance with the procedures of DIN 53446. Hydrogen cyanide was detected in the smoke gases. The changes in composition of the smoke gases with time and heavy components in the smoke were examined qualitatively. Particulates and liquids in the smoke were trapped in an ice trap for analysis. The toxicity of the smoke and smoke gases to rats was also measured. The carbon monoxide binding in rat blood was detected via carboxyhemoglobin measurement. Frequently, the fireproofing additives gave rise to a higher heat of combustion, but even at lower heats the smoke contained toxic gases. ... In a room lethal amounts of hydrogen cyanide are formed from modacrylics and Flamentin-flameproof cotton at the lower temp and from wool at the higher temp.
[Kallonen R et al; Tutkimuksia-Valt Tek Tutkimuskeskus 278: 56 (1984)]**PEER REVIEWED**

The toxicology of gases, vapors, mists, and fumes which workers may be exposed to in an occupational setting are reviewed. Included are the asphyxiant gases carbon dioxide, nitrogen, methane, carbon monoxide, hydrogen cyanide, and hydrogen sulfide, and the irritant gases ammonia, chlorine, ozone, phosgene, sulfur dioxide, and oxides of nitrogen. Industries whose workers may be at at risk of being exposed to these agents are numerous. They include various industries involving chemical refining, welding, mining, degreasing, electoplating, bleaching, sewage treatment industries.
[Seaton A, Morgan WKC; Occupational Lung Diseases 2: 609-42 (1988)]**PEER REVIEWED**

NIOSH (NOES Survey 1981-1983) has statistically estimated that 3,780 workers (254 of these are female) are potentially exposed to hydrogen cyanide in the US(1). Occupational exposure to hydrogen cyanide may occur through inhalation and dermal contact with this compound at workplaces where hydrogen cyanide is produced or used(SRC). The general population may be exposed to hydrogen cyanide from automobile exhaust and waste incinerators(SRC).
[(1) NIOSH; National Occupational Exposure Survey (NOES) (1983)]**PEER REVIEWED**

Body Burden:

Hydrogen cyanide is present in human being's blood(1). People who smoke or consume vegetables having a relatively high hydrogen cyanide content may have slightly higher blood levels(1).
[(1) Pesce LD; Kirk-Othmer Encycl Chem Technol 4th ed. Kroschwitz JI, ed. NY, NY: John Wiley and Sons 7: 758-82 (1993)]**PEER REVIEWED**

Natural Pollution Sources:

Molecular hydrogen cyanide may be produced naturally by microorganisms as well as from the cyanogenic degradation of glycosides.
[Nat'l Research Council Canada; The Effect of Cyanides on Aquatic Organisms With Emphasis Upon Fresh Water Fishes p.10 (1976) NRCC No.19246]**PEER REVIEWED**

Many plants may synthesize cyanoglucosides which upon decomposition may lead to the formation of free cyanide.
[Nat'l Research Council Canada; The Effect of Cyanides on Aquatic Organisms with Emphasis Upon Fresh Water Fishes p.47 (1976) NRCC No.19246]**PEER REVIEWED**

Many photosynthetic microganisms among the blue-green algae can produce free cyanide in the process of nitrate metabolism. ... Anacystis nidulans, a microscopic blue-green algae, used histidine to release substantial amounts of hydrogen cyanide, raising its concn in the culture medium to 0.5 mg/l in 3 hr.
[Nat'l Research Council Canada; The Effect of Cyanides on Aquatic Organisms with Emphasis Upon Fresh Water Fishes p.48 (1976) NRCC No.19246]**PEER REVIEWED**

Laetrile and amygdalin-containing fruit pits /cherries, peaches, apricots, apples, and pears/.
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-6 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Apricot kernels contain a cyanogenic substance called amygdalin, which after hydrolysis (after ingestion), liberates hydrocyanic acid.
[Lasch EE, El Shawa R; Pediatrics 68 (1): 5-7 (1981)]**PEER REVIEWED**

The cyanide contents were found to be below 20 ppm as hydrogen cyanide except for 163 ppm in bainiku-ekisu (condensed extract of the edible portion). The free cyanide concentrations determined without beta-glucosidase were in the range of 0.6 taken concerning the amount of beta-glucosidase used.
[Maitani T, Uchiyama S; Bull Natl Inst Hyg Sci (Tokyo) 0 (103): 123-25 (1985)]**PEER REVIEWED**

Artificial Pollution Sources:

Yields of hydrogen cyanide varied significantly under different cigarette smoking conditions.
[Rickert WS et al J Toxicol Environ Health 12 (1): 39-54 (1983)]**PEER REVIEWED**

Hydrogen cyanide may be generated in blast furnaces, gas works, and coke ovens.
[Sittig M; Handbook of Toxic and Hazardous Chemicals p.376 (1981)]**PEER REVIEWED**

Five organic nitrogen species, one of which was hydrogen cyanide, were identified by gas chromatography with a nitrogen-phosphorus detector in the offgas from 2 oil shale retorting processes. The organic nitrogen species were present in amounts on the order of tens of ppm which comprise approx 1-2% of the gas-phase ammonia nitrogen concn in the offgas. Most of the nitrogen species except hydrogen cyanide appear to be reasonably stable at least in a qualitative sense for a period of at least several months in a bomb sample.
[Sklarew DS, Hayes DL; Environ Sci Technol 18 (8): 600-3 (1984)]**PEER REVIEWED**

... In a room lethal amounts of hydrogen cyanide are formed from modacrylics and Flamentin-flameproof cotton at the lower temp and from wool at the higher temp.
[Kallonen R et al; Tutkimuksia-Valt Tek Tutkimuskeskus 278: 56 (1984)]**PEER REVIEWED**

Hydrogen cyanide's production and use as a starting material in the manufacture of acrylates, cyanide salts, herbicides and dyes as well as its former use as a fumigant(1,2) may result in its release to the environment through various waste streams(SRC).
[(1) Lewis RJ; Hawley's Condensed Chemical Dictionary. 13th ed. NY, NY: Van Nostrand Reinhold Co., p. 588 (1997) (2) Pesce LD; Kirk-Othmer Encycl Chem Technol. Kroschwitz JI, ed. NY, NY. John Wiley and Sons 7: 758-82 (1993)]**PEER REVIEWED**

Environmental Fate:

TERRESTRIAL FATE: By analogy to the fate of cyanides in water, it is predicted that the fate in soil would be pH dependent. Cyanide may occur in the form of hydrogen cyanide, alkali metal salts, or immobile metallocyanide complexes. At soil surfaces with pH <9.2, it is expected that volatilization of hydrogen cyanide would be an important loss mechanism for cyanides. In subsurface soil, cyanide present at low concentrations would probably biodegrade. In soil with pH <9.2, hydrogen cyanide is expected to be highly mobile, and in cases where cyanide levels are toxic to microorganisms (ie, landfills, spills), this compound may leach into groundwater.
[DHHS/ATSDR; Toxicological Profile for Cyanide (Draft) p.77 (1/88)]**PEER REVIEWED**

ATMOSPHERIC FATE: The reaction of hydrogen cyanide with photochemically generated hydroxyl radicals proceeds fairly slowly. Based on a reaction rate constant of 3x10-14 cu m/(molecules-sec) at 25 deg C, and assuming an ambient hydroxyl radical concentration of 8x10+5 molecules/cu m, the half-life for the reaction of hydrogen cyanide vapor with hydroxyl radicals in the atmosphere has been approximately 334 days. Hydrogen cyanide is expected to be resistent to direct photolysis. The relatively slow rate of degradation of hydrogen cyanide suggests that this compound has the potential to be transported over long distances before being removed by physical or chemical processes. Since hydrogen cyanide is miscible in water, it appears that wet deposition may be an important fate process. Metal cyanide particles are expected to be removed from air by both wet and dry deposition.
[DHHS/ATSDR; Toxicological Profile for Cyanide (Draft) p.76 (1/88)]**PEER REVIEWED**

TERRESTRIAL FATE: Hydrogen cyanide is expected to have high mobility in soils(1). Volatilization of hydrogen cyanide from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 1.33X10-4 atm-cu m/mole(2). The potential for volatilization of hydrogen cyanide from dry soil surfaces may exist(SRC) based upon a vapor pressure of 742 mm Hg(3). Hydrogen cyanide can be biodegraded by acclimated microbial cultures and sludges, but is usually toxic at high concentrations to unacclimated microbial systems(4).
[(1) Roy WR; Groundwater Contamination From Municipal Landfills in the USA. in Contam Groundwaters, Adriano DC et al eds. Sci Rev Northwood, UK (1994) (2) Gaffney JS et al; Environ Sci Technol 21: 519-23 (1987) (3) Daubert TE, Danner RP; Physical and Thermodynamic Properties of Pure Chemicals Data Compilation Washington, DC: Taylor and Francis (1989) (4) Raef et al; Water Res 11: 485-92 (1977)]**PEER REVIEWED**

AQUATIC FATE: Hydrogen cyanide is not expected to adsorb to suspended solids and sediment in water(1). Volatilization from water surfaces is expected(2) based upon a Henry's Law constant of 1.33X10-4 atm-cu m/mole(3). Using this Henry's Law constant and an estimation method(2), volatilization half-lives for a model river and model lake are 3 hours and 3 days, respectively(SRC). According to a classification scheme(4), an estimated BCF of 3(SRC), from its log Kow of -0.25(5) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is low (SRC). Hydrogen cyanide can be biodegraded by acclimated microbial cultures and sludges, but is usually toxic at high concentrations to unacclimated microbial systems(7).
[(1) Roy WR; Groundwater Contamination From Municipal Landfills in the USA. in Contam Groundwaters, Adriano DC et al eds. Sci Rev Northwood, UK (1994) (2) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 15-1 to 15-29 (1990) (3) Gaffney JS et al; Environ Sci Technol 21: 519-23 (1987) (4) Franke C et al; Chemosphere 29: 1501-14 (1994) (5) Hansch C et al; Exploring QSAR. Hydrophobic, Electronic, and Steric Constants. ACS Prof Ref Book. Heller SR, consult. ed., Washington, DC: Amer Chem Soc p. 3 (1995) (6) Meylan WM et al; Environ Toxicol Chem 18: 664-72 (1999) (7) Raef et al; Water Res 11: 485-92 (1977)]**PEER REVIEWED**

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), hydrogen cyanide, which has a vapor pressure of 742 mm Hg at 25 deg C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase hydrogen cyanide is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 535 days(SRC), calculated from its rate constant of 3X10-14 cu cm/molecule-sec at 25 deg C(3).
[(1) Bidleman TF; Environ Sci Technol 22: 361-367 (1988) (2) Daubert TE, Danner RP; Physical and Thermodynamic Properties of Pure Chemicals Data Compilation Washington, DC: Taylor and Francis, (1989) (3) Atkinson R; J Phys Chem Ref Data Monograph 1 (1989)]**PEER REVIEWED**

Environmental Biodegradation:

Waste water treatment; sludge digestion: at 25 mg/l: no adverse effect in 24 days; at 30 mg/l: initial retarding effect for 6 days; at 50 mg/l: 10% reduction in gas production.
[Verschueren, K. Handbook of Environmental Data on Organic Chemicals. 3rd ed. New York, NY: Van Nostrand Reinhold Co., 1996. 1119]**PEER REVIEWED**

Bacteria and protozoa may degrade cyanide by converting it to carbon dioxide and ammonia.
[Leduc G et al; Natur Can 100: 1 (1973) as cited in USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-24 (1980) EPA 440/5-80-037]**PEER REVIEWED**

The metabolism of cyanide (10 mg/l) was studied using acclimated heterogeneous cultures in an aerated microferometer(1). It was determined that cyanide was readily biodegradable by acclimated cultures but highly toxic to non-acclimated cultures(1). The fungus Gloeocercospora sorghi was shown to convert hydrogen cyanide to formamide in the presence of water(2).
[(1) Raef et al; Water Res 11: 485-92 (1977) (2) Wyatt JM, Palmer SJ; Biodegradation of Nitriles and Cyanide. in Natural and Synthetic Materials (1991)]**PEER REVIEWED**

Environmental Abiotic Degradation:

Cyanide is converted to cyanate during chlorination of water supplies. An alkaline pH favors the oxidation by chlorine, whereas an acid pH favors volatilization of hydrogen cyanide into the atmosphere.
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-25 (1980) EPA 440/5-80-037]**PEER REVIEWED**

In the presence of titanium dioxide powder, photocatalytic oxidation of cyanide proceeds at significant rates in both high intensity artificial sunlight and unfocused sunlight. With titanium dioxide powder present, more than 99% of a 1 mM (26 mg/l) solution of cyanide ion was oxidized by exposure to sunlight for two days. In the absence of titanium dioxide powder, little or no oxidation occurred.
[Callahan, M.A., M.W. Slimak, N.W. Gabel, et al. Water-Related Environmental Fate of 129 Priority Pollutants. Volume I. EPA-440/4 79-029a. Washington, DC: U.S. Environmental Protection Agency, December 1979.p. 12-2]**PEER REVIEWED**

The rate constant for the vapor-phase reaction of hydrogen cyanide with photochemically-produced hydroxyl radicals has been measured as 3X10-14 cu cm/molecule-sec at 25 deg C(1). This corresponds to an atmospheric half-life of about 535 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Hydrogen cyanide is not expected to directly photolyze due to the lack of absorption in the environmental UV spectrum. A pKa value of 9.2(3) indicates that hydrogen cyanide may dissociate and exist as an anion at high pH(SRC). Hydrogen cyanide may react with metals commonly found in soils resulting in the formation of inorganic complexes(4).
[(1) Atkinson R; J Phys Chem Ref Data Monograph 1 (1989) (2) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 7-4, 7-5 (1990) (3) USEPA; Treatability Manual Vol 1. Treatability Data. USEPA-600/8-80-042 (1980) (4) Pesce LD; Kirk-Othmer Encycl Chem Technol 4th ed. Kroschwitz JI, ed. NY, NY: John Wiley and Sons 7: 758-82 (1993)]**PEER REVIEWED**

Environmental Bioconcentration:

Cyanide is not accumulated or stored in any mammalian species that have been studied.
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-1 (1980) EPA 440/5-80-037]**PEER REVIEWED**

An estimated BCF of 3 was calculated for hydrogen cyanide(SRC), using a log Kow of -0.25(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).
[(1) Hansch C et al; Exploring QSAR. Hydrophobic, Electronic, and Steric Constants. ACS Prof Ref Book. Heller SR, consult. ed., Washington, DC: Amer Chem Soc p. 3 (1995) (2) Meylan WM et al; Environ Toxicol Chem 18: 664-72 (1999) (3) Franke C et al; Chemosphere 29: 1501-14 (1994)]**PEER REVIEWED**

Soil Adsorption/Mobility:

Hydrogen cyanide is not strongly partitioned into the sediments or suspended adsorbents, primarily due to its high solubility in water.
[Callahan, M.A., M.W. Slimak, N.W. Gabel, et al. Water-Related Environmental Fate of 129 Priority Pollutants. Volume I. EPA-440/4 79-029a. Washington, DC: U.S. Environmental Protection Agency, December 1979.p. 12-6]**PEER REVIEWED**

Cyanide mobility is least where soils exhibit low pH, high concn of free iron oxides, and positively charged particles (eg, kaolin, chlorite, gibbsite). Mobility is greatest at high pH, high concn of free calcium carbonate (high negative charge) and low clay content.
[Callahan, M.A., M.W. Slimak, N.W. Gabel, et al. Water-Related Environmental Fate of 129 Priority Pollutants. Volume I. EPA-440/4 79-029a. Washington, DC: U.S. Environmental Protection Agency, December 1979.p. 12-6]**PEER REVIEWED**

Adsorption of hydrogen cyanide by montmorillonitic clays is fairly weak and is decreased by the presence of water.
[Callahan, M.A., M.W. Slimak, N.W. Gabel, et al. Water-Related Environmental Fate of 129 Priority Pollutants. Volume I. EPA-440/4 79-029a. Washington, DC: U.S. Environmental Protection Agency, December 1979.p. 12-6]**PEER REVIEWED**

Hydrogen cyanide is only weakly absorbed by organic matter(1) and its mobility in soil surfaces is expected to be high(SRC).
[(1) Roy WR; Groundwater Contamination From Municipal Landfills in the USA. in Contam Groundwaters, Adriano DC et al eds. Sci Rev Northwood, UK (1994)]**PEER REVIEWED**

Volatilization from Water/Soil:

Volatilization is expected to be an important (if not dominant) fate process for hydrogen cyanide. At pH <9.2, most of the free cyanide should exist as hydrogen cyanide, a volatile form of cyanide. Wide variations in the rate of volatilization are expected since this process is affected by a number of parameters including temperature, pH, wind speed, and cyanide concentration. Because of the lack of data on this topic, the half-life for this process could not be determined.
[ATSDR; Toxicological Profile for Cyanide (Draft) p.77 (1/88)]**PEER REVIEWED**

The Henry's Law constant for hydrogen cyanide is 1.33X10-4 atm-cu m/mole(1). This Henry's Law constant indicates that hydrogen cyanide is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 3 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 3 days(SRC). Hydrogen cyanide's Henry's Law constant(1) indicates that volatilization from moist soil surfaces may occur(SRC). The potential for volatilization of hydrogen cyanide from dry soil surfaces may exist(SRC) based upon a vapor pressure of 742 mm Hg(3).
[(1) Gaffney JS et al; Environ Sci Technol 21: 519-23 (1987) (2) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 15-1 to 15-29 (1990) (3) Daubert TE, Danner RP; Physical and Thermodynamic Properties of Pure Chemicals Data Compilation Washington, DC: Taylor and Francis (1989)]**PEER REVIEWED**

Environmental Water Concentrations:

A survey ... examined ... total cyanide /and found/ levels of total cyanide were often recorded as high as 30-60 ug/l. In small rivers /in Canada/ with a discharge rate of 28 to 140 cu m/sec and medium size rivers (140 to 710 cu m/sec), peaks of cyanide were more frequent in fall and winter during mineral runoff. In large rivers (430 to 2100 cu m/sec) the peak cyanide levels occurred during and/or after the May-June runoff.
[Nat'l Research Council Canada; The Effect of Cyanides on Aquatic Organisms with Emphasis Upon Fresh Water Fishes p.51 (1976) NRCC No.19246]**PEER REVIEWED**

Effluent Concentrations:

Hydrogen cyanide emissions from Pratt and Whitney aircraft jet turbine 9D engine operating at several power settings ranged from 8.4 to 42 ppb as measured in the tailpipe.
[Verschueren, K. Handbook of Environmental Data on Organic Chemicals. 3rd ed. New York, NY: Van Nostrand Reinhold Co., 1996. 1119]**PEER REVIEWED**

In combustion products of polyvinyl chloride, aromatic polyamides and foam polyurethanes, acrylonitrile copolymers, and fluororganic polymers, the main toxic components were hydrochloric acid plus carbon monoxide, mainly hydrogen cyanide (HCN), carbon monoxide plus HCN, and hydrofluoric acid, resp. Thus, carbon monoxide is not always the most toxic component of the polymer combustion. The composition and toxicity of the combustion products can be predicted from the composition of the polymeric materials.
[Eitingon AI; Gig Sanit (4): 20-23 (1985)]**PEER REVIEWED**

Hydrogen cyanide was identified, not quantified, in the effluent of coated steel plates heated to 350 deg C(1).
[(1) Henricks-Eckerman ML et al; Am Ind Hyg Assoc J 51: 241-44 (1990)]**PEER REVIEWED**

Atmospheric Concentrations:

URBAN/SUBURBAN: Hydrogen cyanide was detected in ambient air of Sofia, Bulgaria at a mean concn of 1.08 ug/cu m, and detected at a mean concn of 2.4 ug/cu m in industrial areas(1).
[(1) Kalpasanov Y, Kurchatova G; J Air Pollut Control Assoc 26: 981-85 (1976)]**PEER REVIEWED**

Food Survey Values:

The nutritive value of African star apple, C albidum, was evaluated chemically. ... The hydrocyanic acid content was 5.4 mg/100 g in the peel and 6.8 mg/100 g in the pulp.
[Edem DO et al; Food Chem 14 (4): 303-12 (1984)]**PEER REVIEWED**

Plant Concentrations:

The hydrocyanic acid content of peeled cassava tubers from various localities in Eastern Nigeria (major cassava growing and consuming area) varied from 26 + or - 1.6 to 38 + or - 2.6 mg/100 g fresh weight. There was no correlation between the cyanide contents of cassava tubers and locality.
[Ezeala DO, Okoro N; J Food Biochem 10 (2): 125-32 (1986)]**PEER REVIEWED**

Other Environmental Concentrations:

In cigarette smoke: 1,600 ppm.
[Verschueren, K. Handbook of Environmental Data on Organic Chemicals. 3rd ed. New York, NY: Van Nostrand Reinhold Co., 1996. 1119]**PEER REVIEWED**

Environmental Standards & Regulations:

FIFRA Requirements:

A tolerance for residues of the insecticide hydrogen cyanide from postharvest fumigation as a result of application of sodium cyanide is established as follows: in or on citrus fruits.
[40 CFR 180.130 revised at 64 FR 3907, (7/21/99)]**PEER REVIEWED**

Acceptable Daily Intakes:

8.4 mg/day
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-27 (1980) EPA 440/5-80-037]**PEER REVIEWED**

CERCLA Reportable Quantities:

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 10 lb or 4.54 kg. The toll free number of the NRC is (800) 424-8802; In the Washington D.C. metropolitan area (202) 426-2675. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b).
[40 CFR 302.4 (7/1/99)]**PEER REVIEWED**

Releases of CERCLA hazardous substances are subject to the release reporting requirement of CERCLA section 103, codified at 40 CFR part 302, in addition to the requirements of 40 CFR part 355. Hydrocyanic Acid is an extremely hazardous substance (EHS) subject to reporting requirements when stored in amounts in excess of its threshold planning quantity (TPQ) of 100 lbs.
[40 CFR 355 (7/1/99)]**PEER REVIEWED**

RCRA Requirements:

P063; As stipulated in 40 CFR 261.33, when hydrogen cyanide, as a commercial chemical product or manufacturing chemical intermediate or an off-specification commercial chemical product or a manufacturing chemical intermediate, becomes a waste, it must be managed according to federal and/or state hazardous waste regulations. Also defined as a hazardous waste is any container or inner liner used to hold this waste or any residue, contaminated soil, water, or other debris resulting from the cleanup of a spill, into water or on dry land, of this waste. Generators of small quantities of this waste may qualify for partial exclusion from hazardous waste regulations (40 CFR 261.5(e)).
[40 CFR 261.33 (7/1/99)]**PEER REVIEWED**

/SRP:/ D003; A solid waste containing hydrogen cyanide may become characterized as a hazardous waste when subjected to testing for reactivity as stipulated in 40 CFR 261.23, and if so characterized, must be managed as a hazardous waste.
[40 CFR 261.23 (7/1/99)]**PEER REVIEWED**

Atmospheric Standards:

This action promulgates standards of performance for equipment leaks of Volatile Organic Compounds (VOC) in the Synthetic Organic Chemical Manufacturing Industry (SOCMI). The intended effect of these standards is to require all newly constructed, modified, and reconstructed SOCMI process units to use the best demonstrated system of continuous emission reduction for equipment leaks of VOC, considering costs, non air quality health and environmental impact and energy requirements. Hydrogen cyanide is produced, as an intermediate or a final product, by process units covered under this subpart.
[40 CFR 60.489 (7/1/99)]**PEER REVIEWED**

Clean Water Act Requirements:

Hydrogen cyanide is designated as a hazardous substance under section 311(b)(2)(A) of the Federal Water Pollution Control Act and further regulated by the Clean Water Act Amendments of 1977 and 1978. These regulations apply to discharges of this substance. This designation includes any isomers and hydrates, as well as any solutions and mixtures containing this substance.
[40 CFR 116.4 (7/1/99)]**QC REVIEWED**

Toxic pollutant designated pursuant to section 307(a)(1) of the Federal Water Pollution Control Act and is subject to effluent limitations. /Cyanides/
[40 CFR 401.15 (7/1/99)]**QC REVIEWED**

State Drinking Water Guidelines:

(FL) FLORIDA 10,000 ug/l
[USEPA/Office of Water; Federal-State Toxicology and Risk Analysis Committee (FSTRAC). Summary of State and Federal Drinking Water Standards and Guidelines (11/93)]**QC REVIEWED**

Allowable Tolerances:

A tolerance for residues of the insecticide hydrogen cyanide from postharvest fumigation as a result of application of sodium cyanide is established as follows: 50 ppm in or on citrus fruits.
[40 CFR 180.130 revised at 64 FR 3907, (7/21/99)]**PEER REVIEWED**

Chemical/Physical Properties:

Molecular Formula:

C-H-N
**PEER REVIEWED**

Molecular Weight:

27.03
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 822]**PEER REVIEWED**

Color/Form:

Colorless gas or liquid
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 822]**PEER REVIEWED**

Water-white liquid below 26.5 deg C
[Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 13th ed. New York, NY: John Wiley & Sons, Inc. 1997. 588]**PEER REVIEWED**

Colorless to bluish white liquid
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

Colorless or pale-blue liquid or gas (above 78 degrees F) ... [Note: Often used as a 96% solution in water].
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 168]**PEER REVIEWED**

Odor:

Characteristic sweetish, like almond
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

... Bitter, almond-like odor ...
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 168]**PEER REVIEWED**

Taste:

Bitter, burning taste
[Doull, J., C.D.Klassen, and M.D. Amdur (eds.). Casarett and Doull's Toxicology. 3rd ed., New York: Macmillan Co., Inc., 1986. 888]**PEER REVIEWED**

Boiling Point:

25.6 deg C
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 822]**PEER REVIEWED**

Melting Point:

-13.4 deg C
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 822]**PEER REVIEWED**

Corrosivity:

Although HCN is a weak acid and normally not considered corrosive, it has a corrosive effect under two special conditions: (1) water solutions of HCN cause transcrystalline stress-cracking of carbon steels under stress even at room temperature and in dilute solution; (2) water solutions of HCN containing sulfuric acid as a stabilizer severely corrode steel above 40 deg C and stainless steels above 80 deg C.
[Kirk-Othmer Encyclopedia of Chemical Technology. 3rd ed., Volumes 1-26. New York, NY: John Wiley and Sons, 1978-1984.,p. 7(79) 309]**PEER REVIEWED**

Liquid hydrogen cyanide will attack some forms of plastics, rubber, and coatings.
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) Publication No. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981.2]**PEER REVIEWED**

Critical Temperature & Pressure:

Critical temperature: 183.5 deg C; Critical pressure: 5.4 MPa
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V7 754]**PEER REVIEWED**

Density/Specific Gravity:

0.687 g/cu cm
[Lide, D.R. (ed.). CRC Handbook of Chemistry and Physics. 79th ed. Boca Raton, FL: CRC Press Inc., 1998-1999. ,p. 3-197]**PEER REVIEWED**

Dissociation Constants:

pKa of 9.2
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-7 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Heat of Combustion:

642 kJ/mol
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V7 754]**PEER REVIEWED**

Heat of Vaporization:

25.2 KJ/mol
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V7 754]**PEER REVIEWED**

Octanol/Water Partition Coefficient:

log Kow= -0.25
[Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995. 3]**PEER REVIEWED**

pH:

Very weak acid (does not redden litmus)
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 822]**PEER REVIEWED**

Solubilities:

Miscible with alcohol; slightly sol in ether
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 822]**PEER REVIEWED**

Water solubility = 1,000,000 mg/l @ 25 deg C
[Kirk-Othmer Encyclopedia of Chemical Technology. 3rd ed., Volumes 1-26. New York, NY: John Wiley and Sons, 1978-1984.,p. V13 (78) 467]**PEER REVIEWED**

Spectral Properties:

Index of refraction: 1.2675 @ 10 deg C
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V7 754]**PEER REVIEWED**

IR: 1642 (Documentation of Molecular Spectroscopy Collection)
[Weast, R.C. and M.J. Astle. CRC Handbook of Data on Organic Compounds. Volumes I and II. Boca Raton, FL: CRC Press Inc. 1985.,p. V1 751]**PEER REVIEWED**

MASS: 2 (Atlas of Mass Spectral Data, John Wiley & Sons, New York)
[Weast, R.C. and M.J. Astle. CRC Handbook of Data on Organic Compounds. Volumes I and II. Boca Raton, FL: CRC Press Inc. 1985.,p. V1 751]**PEER REVIEWED**

Vapor Density:

0.94 (Air= 1)
[Verschueren, K. Handbook of Environmental Data on Organic Chemicals. 3rd ed. New York, NY: Van Nostrand Reinhold Co., 1996. 1119]**PEER REVIEWED**

Vapor Pressure:

742 mm Hg @ 25 deg C
[Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989.]**PEER REVIEWED**

Other Chemical/Physical Properties:

1 mg/cu m= 0.9 ppm; 1 ppm= 1.13 mg/cu m
[Verschueren, K. Handbook of Environmental Data on Organic Chemicals. 3rd ed. New York, NY: Van Nostrand Reinhold Co., 1996. 1119]**PEER REVIEWED**

Henry's Law constant = 1.33X10-4 atm-cu m/mol @ 25 deg C
[Gaffney JS et al; Environ Sci Technol 21: 519-23 (1987)]**PEER REVIEWED**

Hydroxyl radical rate constant = 3.00X10-14 cu m/molc-sec @ 25 deg C
[Atkinson R; Journal of Physical And Chemical Reference Data. Monograph No 1 (1989)]**PEER REVIEWED**

Chemical Safety & Handling:

DOT Emergency Guidelines:

Health: Toxic; may be fatal if inhaled, ingested or absorbed through skin. Inhalation or contact with some of these materials will irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Fire or explosion: Highly flammable: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion and poison hazard indoors, outdoors or in sewers. Those substances designated with a "P" may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water. Health: Toxic; may be fatal if inhaled, ingested or absorbed through skin. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Public safety: Call Emergency Response Telephone Number ... . Isolate spill or leak area immediately for at least 100 to 200 meters (330 to 660 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate closed spaces before entering. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Protective clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing which is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Evacuation: Spill: ... Fire: If tank, rail car or tank truck is involved in a fire, isolate for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Fire: CAUTION: All these products have a very low flash point. Use of water spray when fighting fire may be inefficient. Small fires: Dry chemical, CO2, water spray or alcohol-resistant foam. Large fires: Water spray, fog or alcohol-resistant foam. Move containers from fire area if you can do it without risk. Dike fire control water for later disposal; do not scatter the material. Use water spray or fog; do not use straight streams. Fire involving tanks or car/trailer loads: Fight fire from maximum distance or use unmanned hose holders or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. For massive fire use unmanned hose holders or monitor nozzles; if this is impossible, withdraw from area and let fire burn. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Spill or leak: Fully encapsulating, vapor protective clothing should be worn for spills and leaks with no fire. ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. A vapor suppressing foam may be used to reduce vapors. Small spills: Absorb with earth, sand or other non-combustible material and transfer to containers for later disposal. Use clean non-sparking tools to collect absorbed material. Large spills: Dike far ahead of liquid spill for later disposal. Water spray may reduce vapor; but may not prevent ignition in closed spaces. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

First aid: Move victim to fresh air. Call 911 or emergency medical service. Apply artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. Wash skin with soap and water. Keep victim warm and quiet. Effects of exposure (inhalation, ingestion or skin contact) to substance may be delayed. Ensure that medical personnel are aware of the material(s) involved, and take precautions to protect themselves. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Health: TOXIC; Extremely Hazardous. May be fatal if inhaled or absorbed through skin. Initial odor may be irritating or foul and may deaden your sense of smell. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control may cause pollution. /Hydrogen cyanide, anhydrous, stabilized; Hydrogen cyanide, stabilized/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-117]**QC REVIEWED**

Fire or explosion: These materials are extremely flammable. May form explosive mixtures with air. May be ignited by heat, sparks or flames. Vapors from liquefied gas are initially heavier than air and spread along ground. Vapors may travel to source of ignition and flash back. Runoff may create fire or explosion hazard. Containers may explode when heated. Ruptured cylinders may rocket. /Hydrogen cyanide, anhydrous, stabilized; Hydrogen cyanide, stabilized/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-117]**QC REVIEWED**

Public safety: CALL Emergency Response Telephone Number ... . Isolate spill or leak area immediately for at least 100 to 200 meters (330 to 660 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Many gases are heavier than air and will spread along ground and collect in low or confined areas (sewers, basements, tanks). Keep out of low areas. Ventilate closed spaces before entering. /Hydrogen cyanide, anhydrous, stabilized; Hydrogen cyanide, stabilized/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-117]**QC REVIEWED**

Protective clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing which is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations. /Hydrogen cyanide, anhydrous, stabilized; Hydrogen cyanide, stabilized/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-117]**QC REVIEWED**

Evacuation: Spill: ... Fire: If tank, rail car or tank truck is involved in a fire, ISOLATE for l600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions. /Hydrogen cyanide, anhydrous, stabilized; Hydrogen cyanide, stabilized/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-117]**QC REVIEWED**

Fire: DO NOT EXTINGUISH A LEAKING GAS FIRE UNLESS LEAK CAN BE STOPPED. Small fires: Dry chemical, CO2, water spray or regular foam. Large fires: Water spray, fog or regular foam. Move containers from fire area if you can do it without risk. Damaged cylinders should be handled only by specialists. Fire involving tanks: Fight fire from maximum distance or use unmanned hose holders or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Do not direct water at source of leak or safety devices; icing may occur. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. /Hydrogen cyanide, anhydrous, stabilized; Hydrogen cyanide, stabilized/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-117]**QC REVIEWED**

Spill or leak: ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). All equipment used when handling the product must be grounded. Fully encapsulating, vapor protective clothing should be worn for spills and leaks with no fire. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Do not direct water at spill or source of leak. If possible, turn leaking containers so that gas escapes rather than liquid. Prevent entry into waterways, sewers, basements or confined areas. Isolate area until gas has dispersed. Consider igniting spill or leak to eliminate toxic gas concerns. /Hydrogen cyanide, anhydrous, stabilized; Hydrogen cyanide, stabilized/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-117]**QC REVIEWED**

First aid: Move victim to fresh air. Call 911 or emergency medical service. Apply artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. In case of contact with liquefied gas, thaw frosted parts with lukewarm water. Keep victim warm and quiet. Keep victim under observation. Effects of contact or inhalation may be delayed. Ensure that medical personnel are aware of the material(s) involved, and take precautions to protect themselves. /Hydrogen cyanide, anhydrous, stabilized; Hydrogen cyanide, stabilized/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-117]**QC REVIEWED**

Health: Toxic; may be fatal if inhaled, ingested or absorbed through skin. Inhalation or contact with some of these materials will irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Fire or explosion: Highly flammable: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion and poison hazard indoors, outdoors or in sewers. Those substances designated with a "P" may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Public safety: Call Emergency Response Telephone Number ... . Isolate spill or leak area immediately for at least 100 to 200 meters (330 to 660 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate closed spaces before entering. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Protective clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing which is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Evacuation: Spill: ... Fire: If tank, rail car or tank truck is involved in a fire, isolate for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Fire: CAUTION: All these products have a very low flash point. Use of water spray when fighting fire may be inefficient. Small fires: Dry chemical, CO2, water spray or alcohol-resistant foam. Large fires: Water spray, fog or alcohol-resistant foam. Move containers from fire area if you can do it without risk. Dike fire control water for later disposal; do not scatter the material. Use water spray or fog; do not use straight streams. Fire involving tanks or car/trailer loads: Fight fire from maximum distance or use unmanned hose holders or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. For massive fire use unmanned hose holders or monitor nozzles; if this is impossible, withdraw from area and let fire burn. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Spill or leak: Fully encapsulating, vapor protective clothing should be worn for spills and leaks with no fire. ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. A vapor suppressing foam may be used to reduce vapors. Small spills: Absorb with earth, sand or other non-combustible material and transfer to containers for later disposal. Use clean non-sparking tools to collect absorbed material. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

First aid: Move victim to fresh air. Call 911 or emergency medical service. Apply artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. Wash skin with soap and water. Keep victim warm and quiet. Effects of exposure (inhalation, ingestion or skin contact) to substance may be delayed. Ensure that medical personnel are aware of the material(s) involved, and take precautions to protect themselves. /Hydrogen cyanide, anhydrous, stabilized (absorbed); Hydrogen cyanide, solution in alcohol, with not more than 45% Hydrogen cyanide; Hydrogen cyanide, stabilized (absorbed)/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. G-131]**QC REVIEWED**

Odor Threshold:

Detection in air of hydrogen cyanide of an unspecified purity or grade: 1X10-3 mg/l.
[Fazzalari, F.A. (ed.). Compilation of Odor and Taste Threshold Values Data. ASTM Data Series DS 48A (Committee E-18). Philadelphia, PA: American Society for Testing and Materials, 1978. 87]**PEER REVIEWED**

High odor threshold was 5 mg/cu m; Low odor threshold was 0.9 mg/cu m.
[Ruth JH; Am Ind Hyg Assoc J 47: A-142-51 (1986)]**PEER REVIEWED**

Skin, Eye and Respiratory Irritations:

Hydrogen cyanide is a mild upper respiratory irritant and may cause slight irritation of the nose and throat. There may also be irritation from skin and eye contact with the liquid.
[Sittig, M. Handbook of Toxic and Hazardous Chemicals and Carcinogens, 1985. 2nd ed. Park Ridge, NJ: Noyes Data Corporation, 1985. 508]**PEER REVIEWED**

Fire Potential:

Flammable and dangerous fire hazard ... May be ignited by fires, heated materials, and sparks.
[ITII. Toxic and Hazarous Industrial Chemicals Safety Manual. Tokyo, Japan: The International Technical Information Institute, 1982. 273]**PEER REVIEWED**

BURNS IN AIR WITH BLUE FLAME
[The Merck Index. 10th ed. Rahway, New Jersey: Merck Co., Inc., 1983. 639]**PEER REVIEWED**

NFPA Hazard Classification:

Health: 4. 4= Materials that, on very short exposure, could cause death or major residual injury, including those that are too dangerous to be approached without specialized protective equipment. A few whiffs of the vapor or gas can cause death, or contact with the vapor or liquid may be fatal, if it penetrates the fire fighter's normal protective gear. The normal full protective clothing and breathing apparatus available to the typical fire fighter will not provide adequate protection against inhalation or skin contact with these materials.
[Fire Protection Guide to Hazardous Materials. 12 ed. Quincy, MA: National Fire Protection Association, 1997. ,p. 325-59]**PEER REVIEWED**

Flammability: 4. 4= This degree includes flammable gases, pyrophoric liquids, and Class IA flammable liquids. The preferred method of fire attack is to stop the flow of material or to protect exposures while allowing the fire to burn itself out.
[Fire Protection Guide to Hazardous Materials. 12 ed. Quincy, MA: National Fire Protection Association, 1997. ,p. 325-59]**PEER REVIEWED**

Reactivity: 2. 2= This degree includes materials that are normally unstable and readily undergo violent chemical change, but are not capable of detonation. This includes materials that can undergo chemical change with rapid release of energy at normal temperatures and pressures and materials that can undergo violent chemical changes at elevated temperatures and pressures. This also includes materials that may react violently with water or that may form potentially explosive mixtures with water. In advanced or massive fires involving these materials, fire fighting should be done from a safe distance or from a protected location.
[Fire Protection Guide to Hazardous Materials. 12 ed. Quincy, MA: National Fire Protection Association, 1997. ,p. 325-59]**PEER REVIEWED**

Flammable Limits:

LOWER 5.6%, UPPER 40.0%
[Fire Protection Guide to Hazardous Materials. 12 ed. Quincy, MA: National Fire Protection Association, 1997. ,p. 49-77]**PEER REVIEWED**

Flash Point:

0 deg F, 18 deg C, (Closed cup)
[Fire Protection Guide to Hazardous Materials. 12 ed. Quincy, MA: National Fire Protection Association, 1997. ,p. 325-59]**PEER REVIEWED**

Autoignition Temperature:

538 DEG C (1000 deg F)
[Fire Protection Guide to Hazardous Materials. 12 ed. Quincy, MA: National Fire Protection Association, 1997. ,p. 325-59]**PEER REVIEWED**

Fire Fighting Procedures:

Fire situation may require evacuation. Allow burning of material until flow of gas can be stopped. Use water spray, dry chemical, "alcohol resistant" foam, or carbon dioxide. Water may be ineffective. Approach fire from upwind. Fight fire from protected location or maximum possible distance.
[Fire Protection Guide to Hazardous Materials. 12 ed. Quincy, MA: National Fire Protection Association, 1997. ,p. 49-77]**PEER REVIEWED**

Evacuation: If fire becomes uncontrollable or container is exposed to direct flame - consider evacuation of one-half (1/2) mile radius. /Hydrogen cyanide, anhydrous, stabilized or hydrocyanic acid, aqueous solution or hydrogen cyanide, liquefied; hydrogen cyanide, anhydrous, stabilized; hydrogen cyanide, anhydrous, stabilized, absorbed in a porous inert material/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 582]**PEER REVIEWED**

If material on fire or involved in fire: Do not extinguish fire unless flow can be stopped. Use water in flooding quantities as fog. Use "alcohol" foam, dry chemical or carbon dioxide. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Solid streams of water may be ineffective. /Hydrogen cyanide, anhydrous, stabilized or hydrocyanic acid, aqueous solution or hydrogen cyanide, liquefied; hydrogen cyanide, anhydrous, stabilized; hydrogen cyanide, anhydrous, stabilized, absorbed in a porous inert material/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 582]**PEER REVIEWED**

Cyanide salts must be protected from large concn of carbon dioxide to avoid hydrogen cyanide liberation. Carbon dioxide fire extinguishers should not be used. /Cyanide salts/
[Kirk-Othmer Encyclopedia of Chemical Technology. 3rd ed., Volumes 1-26. New York, NY: John Wiley and Sons, 1978-1984.,p. 7(79) 326]**PEER REVIEWED**

Toxic Combustion Products:

Extremely toxic vapors /unspecified/ are generated even at ordinary temperatures.
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

Firefighting Hazards:

Flashback along vapor trail may occur.
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

Explosive Limits & Potential:

SEVERE, WHEN EXPOSED TO HEAT OR FLAME ...
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1839]**PEER REVIEWED**

Upper 40%; Lower 5.6%
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 168]**PEER REVIEWED**

Hazardous Reactivities & Incompatibilities:

Incompatibilities: Bases such as caustics, amines.
[Sittig, M. Handbook of Toxic And Hazardous Chemicals. Park Ridge, NJ: Noyes Data Corporation, 1981. 377]**PEER REVIEWED**

Hydrogen cyanide, alcohols and hydrogen chloride: Preparation of alkyliminoformate chlorides by passing hydrogen chloride rapidly into alcoholic hydrogen cyanide proceeds explosively (probably owing to a sudden exotherm), even with strong cooling.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 948]**PEER REVIEWED**

UNDER CERTAIN CONDITIONS, PARTICULARLY CONTACT WITH ALKALINE MATERIALS, HCN CAN DECOMP EXPLOSIVELY.
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1839]**PEER REVIEWED**

Hydrogen cyanide and cyanogen chloride: Cyanogen halides may be prepared by electrolysis of hydrogen cyanide or its salts mixed with halide salts. If ammonium chloride is used as the halide salt, precautions to prevent formation of explosive nitrogen trichloride are necessary.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 964]**PEER REVIEWED**

Avoid addition of such alkaline chemicals as sodium hydroxide, ammonia, calcium hydroxide, and sodium carbonate to hydrogen cyanide since they promote polymerization and induce decomposition, which may cause an explosion. Also, avoid addition of large quantities of acid to hydrogen cyanide, for similar reasons.
[Braker W, Mossman A; Matheson Gas Data Book 6th ED p.387 (1980)]**PEER REVIEWED**

SEVERE /EXPLOSION HAZARD CAN RESULT/ ... BY CHEM REACTION WITH OXIDIZERS.
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1839]**PEER REVIEWED**

Reacts violently with acetaldehyde.
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1839]**PEER REVIEWED**

Amines, oxidizers, acids, sodium hydroxide, calcium hydroxide, sodium carbonate, water, caustics, ammonia [Note: Can polymerize at 122 - 140 degrees F].
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 168]**PEER REVIEWED**

Hazardous Polymerization:

WHEN NOT ABSOLUTELY PURE OR STABILIZED, HYDROGEN CYANIDE POLYMERIZES SPONTANEOUSLY WITH EXPLOSIVE VIOLENCE.
[Sax, N.I. and R.J. Lewis, Sr. (eds.). Hawley's Condensed Chemical Dictionary. 11th ed. New York: Van Nostrand Reinhold Co., 1987. 615]**PEER REVIEWED**

UNDER CERTAIN CONDITIONS, PARTICULARLY CONTACT WITH ALKALINE MATERIALS, HCN CAN POLYMERIZE.
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1839]**PEER REVIEWED**

May polymerize violently after a period of time.
[Fire Protection Guide to Hazardous Materials. 12 ed. Quincy, MA: National Fire Protection Association, 1997. ,p. 49-77]**PEER REVIEWED**

Presence of alkali favors explosive polymerization.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 136]**PEER REVIEWED**

Immediately Dangerous to Life or Health:

50 ppm
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 168]**PEER REVIEWED**

Protective Equipment & Clothing:

Escape purposes only-air escape mask with 5 minute air cylinder. Work purposes-vapor-proof emergency suit or vinyl-coated coverall, plus air mask with clear-view facepiece, speaking diaphragm, demand regulator, and 30 minute cylinder. Rubber gloves; Chemical safety goggles; Quick-opening safety shower.
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

Wear special protective clothing and positive pressure self-contained breathing apparatus.
[Fire Protection Guide to Hazardous Materials. 12 ed. Quincy, MA: National Fire Protection Association, 1997. ,p. 49-77]**PEER REVIEWED**

CARE MUST BE EXERCISED TO PREVENT CONTACT ... WITH SKIN. NEOPRENE OR RUBBER GLOVES SHOULD BE WORN AT ALL TIMES WHEN WORKING WITH HYDROGEN CYANIDE.
[National Research Council. Prudent Practices for Handling Hazardous Chemicals in Laboratories. Washington, DC: National Academy Press, 1981. 46]**PEER REVIEWED**

A toxic air sampling pump has been designed to monitor firefighters' exposure to six toxic air gases. The system is lightweight and versatile, and can be attached between the coat and liner of a firefighter's protective suit. Two fire companies made 90 successful sample runs during several calls. The test results suggest that (1) carbon monoxide gas poses the most serious hazards to firefighters, (2) the concentrations of hydrogen cyanide detected were low enough not to pose an acute health hazard during short-term exposure, and (3) exposure to significant amounts of particulates could have significant long-term health effects.
[Gold A et al; Am Ind Hyg Assoc J 39 (7): 534-39 (1978)]**PEER REVIEWED**

WHERE SKIN CAN BE EXPOSED ... PROTECTIVE CLOTHING, INCLUDING IMPERVIOUS HAND PROTECTION, SHOULD BE PROVIDED. ... /CYANIDES/
[International Labour Office. Encyclopedia of Occupational Health and Safety. Vols. I&II. Geneva, Switzerland: International Labour Office, 1983. 576]**PEER REVIEWED**

Wear appropriate personal protective clothing to prevent skin contact.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 169]**PEER REVIEWED**

Wear appropriate eye protection to prevent eye contact.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 169]**PEER REVIEWED**

Eyewash fountains should be provided in areas where there is any possibility that workers could be exposed to the substance; this is irrespective of the recommendation involving the wearing of eye protection.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 169]**PEER REVIEWED**

Facilities for quickly drenching the body should be provided within the immediate work area for emergency use where there is a possibility of exposure. [Note: It is intended that these facilities provide a sufficient quantity or flow of water to quickly remove the substance from any body areas likely to be exposed. The actual determination of what constitutes an adequate quick drench facility depends on the specific circumstances. In certain instances, a deluge shower should be readily available, whereas in others, the availability of water from a sink or hose could be considered adequate.]
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 169]**PEER REVIEWED**

Recommendations for respirator selection. Max concn for use: 47 ppm. Respirator Class(es): Any supplied-air respirator.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 169]**PEER REVIEWED**

Recommendations for respirator selection. Max concn for use: 50 ppm. Respirator Class(es): Any supplied-air respirator operated in a continuous flow mode. Any self-contained breathing apparatus with a full facepiece. Any supplied-air respirator with a full facepiece.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 169]**PEER REVIEWED**

Recommendations for respirator selection. Condition: Emergency or planned entry into unknown concn or IDLH conditions: Respirator Class(es): Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive pressure mode. Any supplied-air respirator that has a full facepiece and is operated in pressure-demand or other positive pressure mode in combination with an auxiliary self-contained breathing apparatus operated in pressure-demand or other positive pressure mode.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 169]**PEER REVIEWED**

Recommendations for respirator selection. Condition: Escape from suddenly occurring respiratory hazards: Respirator Class(es): Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister /SRP: rebreather or oxygen generating/ providing protection against the compound of concern. Any appropriate escape-type, self-contained breathing apparatus.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 169]**PEER REVIEWED**

Preventive Measures:

Evacuation: If material leaking (not on fire) consider evacuation of one-half (1/2) mile radius based on amount of material spilled, location and weather conditions. /Hydrogen cyanide, anhydrous, stabilized or hydrocyanic acid, aqueous solution or hydrogen cyanide, liquefied; hydrogen cyanide, anhydrous, stabilized; hydrogen cyanide, anhydrous, stabilized, absorbed in a porous inert material/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 582]**PEER REVIEWED**

Personnel protection: Avoid breathing vapors. Keep upwind. ... Avoid bodily contact with the material. ... Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap and water. /Hydrogen cyanide, anhydrous, stabilized or hydrocyanic acid, aqueous solution or hydrogen cyanide, liquefied; hydrogen cyanide, anhydrous, stabilized; hydrogen cyanide, anhydrous, stabilized, absorbed in a porous inert material/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 582]**PEER REVIEWED**

If material not on fire and not involved in fire: Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Attempt to stop leak if without undue personnel hazard. Use water spray to knock-down vapors. /Hydrogen cyanide, anhydrous, stabilized or hydrocyanic acid, aqueous solution or hydrogen cyanide, liquefied; hydrogen cyanide, anhydrous, stabilized; hydrogen cyanide, anhydrous, stabilized, absorbed in a porous inert material/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 582]**PEER REVIEWED**

Employees should wash immediately when skin is wet or contaminated. Remove clothing immediately if wet or contaminated to avoid flammability hazard. Provide emergency showers and eyewash.
[Sittig, M. Handbook of Toxic and Hazardous Chemicals and Carcinogens, 1985. 2nd ed. Park Ridge, NJ: Noyes Data Corporation, 1985. 508]**PEER REVIEWED**

In developing hydrogen cyanide emergency procedures, the following should be kept in mind: (1) The plan must be concise. If it is complicated, it will not serve its purpose. (2) Any plan adopted in any particular plant should be well known to all in that plant. (3) Each individual in the plant should know what he personally must do immediately in the event of an HCN emergency. (4) Any worker whose clothing has absorbed HCN liquid or gas should remove this clothing immediately. Workers wearing respiratory protective devices should not remove them until their clothing has been removed or thoroughly rinsed off. The buddy system should be used in all emergency work in an HCN contaminated area.
[NIOSH; Criteria Document: Hydrogen Cyanide and Cyanide Salts p.31 (1976) DHEW Pub. NIOSH 77-108]**PEER REVIEWED**

Food storage, preparation, and eating shall be prohibited in areas where HCN is used. Smoking and the carrying of tobacco and other smoking materials shall also be prohibited in these areas. Clean and sanitary lunchroom facilities, if provided, must be in non-exposure areas. Work clothing which has been contaminated by absorption of, or contact with, cyanide shall be thoroughly laundered before it is worn again. Clothing-change and locker-room facilities shall be provided in a non-exposure area. Workers should be encouraged to shower after work and to change work clothing frequently. Showers and basin washing facilities shall be located in the locker-room area. /Hydrogen cyanide or cyanide salts/
[NIOSH; Criteria Document: Hydrogen Cyanide and Cyanide Salts p.31 (1976) DHEW Pub. NIOSH 77-108]**PEER REVIEWED**

If the clothing is to be laundered or otherwise cleaned to remove the cyanide, the person performing the operation should be informed of cyanide's hazardous properties. /Cyanides/
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) Publication No. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981.3]**PEER REVIEWED**

PERSONS WHO WORK WITH & AROUND CYANIDE PREPN SHOULD BE GIVEN SPECIFIC DETAILED INSTRUCTIONS ON MANAGEMENT OF CYANIDE POISONING. /CYANIDES/
[Goodman, L.S., and A. Gilman. (eds.) The Pharmacological Basis of Therapeutics. 5th ed. New York: Macmillan Publishing Co., Inc., 1975. 905]**PEER REVIEWED**

Two physician's treatment kits shall be immediately available to trained medical personnel at each plant where there is a potential for the release of, accidental or otherwise, or for contact with, hydrogen cyanide or cyanide salts. ... First-aid kits shall be immediately available at workplaces where there is potential for the release, accidental or otherwise, of hydrogen cyanide or a potential for exposure to cyanide salts. ... Pertinent medical records shall be maintained ... /SRP: for the duraton of employment plus 50 years [29 CFR 1910.1020]/ following the last exposure to hydrogen cyanide or cyanide salts. /Hydrogen cyanide and cyanide salts/
[NIOSH; Criteria Document: Hydrogen Cyanide and Cyanide Salts p.3-4 (1976) DHEW Pub. NIOSH 77-108]**PEER REVIEWED**

Check all valves before and after withdrawing hydrogen cyanide from cylinders. Never trap liquid hydrogen cyanide between two valves.
[Braker W, Mossman A; Matheson Gas Data Book 6th ED p.387 (1980)]**PEER REVIEWED**

Contact lenses should not be worn when working with this chemical.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 169]**PEER REVIEWED**

SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.
**PEER REVIEWED**

SRP: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers.
**PEER REVIEWED**

ALL WORK WITH HYDROGEN CYANIDE MUST BE CONFINED TO HOODS, WHICH SHOULD HAVE A MINIMUM FACE VELOCITY OF 60 LINEAR FT/MIN. WHENEVER WORK WITH HYDROGEN CYANIDE OR RELATED COMPOUNDS IS BEING CARRIED OUT IN A LAB, THERE SHOULD BE AT LEAST TWO PEOPLE IN THE AREA AT ALL TIMES. ... ALL REACTION EQUIPMENT IN WHICH CYANIDES ARE USED OR PRODUCED SHOULD BE PLACED IN OR OVER SHALLOW PANS SO THAT SPILLS OR LEAKS WILL BE CONTAINED. /HYDROGEN CYANIDE/
[National Research Council. Prudent Practices for Handling Hazardous Chemicals in Laboratories. Washington, DC: National Academy Press, 1981. 46]**PEER REVIEWED**

Eyewash facilities and emergency showers shall be provided in areas where contact with ... cyanide salts as either solids or solutions is likely. Work clothing which has been contaminated by absorption of, or contact with, cyanide shall be thoroughly laundered before it is worn again. /Hydrogen cyanide and cyanide salts/
[NIOSH; Criteria Document: Hydrogen Cyanide and Cyanide Salts p.31 (1976) DHEW Pub. NIOSH 77-108]**PEER REVIEWED**

The worker should immediately wash the skin when it becomes contaminated.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 169]**PEER REVIEWED**

Work clothing that becomes wet should be immediately removed due to its flammability hazard.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 169]**PEER REVIEWED**

Stability/Shelf Life:

SOLN SENSITIVE TO LIGHT
[Sax, N.I. and R.J. Lewis, Sr. (eds.). Hawley's Condensed Chemical Dictionary. 11th ed. New York: Van Nostrand Reinhold Co., 1987. 615]**PEER REVIEWED**

Anhydrous hydrogen cyanide is stable at or below room temperature if inhibited with acid (eg 0.1% sulfuric acid).
[Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990 136]**PEER REVIEWED**

Shipment Methods and Regulations:

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./
[49 CFR 171.2 (7/1/99)]**PEER REVIEWED**

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.
[IATA. Dangerous Goods Regulations. 40th Ed. Montreal, Canada and Geneva, Switzerland: International Air Transport Association, Dangerous Goods Regulations, 1999. 163]**PEER REVIEWED**

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.
[IMDG; International Maritime Dangerous Goods Code; International Maritime Organization p.6163 (1998)]**PEER REVIEWED**

Storage Conditions:

Keep cylinders of hydrogen cyanide (HCN) cool and away from open flames. Make certain that HCN cylinders are adequately supported and grounded during storage and emptying. Store cylinders in a vertical position. Do not drop cylinders or damage them by impact. Cylinders must be returned to the supplier within 90 days of the filling date marked on the cylinders, regardless of whether or not the contents have been used. This is due to the possibility of HCN becoming unstable over time. If there is any indication that the HCN is becoming unstable, such as a darkening of the product or an increase in cylinder pressure, contact the supplier immediately for instructions.
[Braker W, Mossman A; Matheson Gas Data Book 6th ED p.387 (1980)]**PEER REVIEWED**

... SHOULD BE STORED IN COOL, WELL-VENTILATED PLACE, OUT OF DIRECT RAYS OF SUN, AWAY FROM ... FIRE HAZARD, & SHOULD BE PERIODICALLY INSPECTED & MONITORED. INCOMPATIBLE MATERIALS SHOULD BE ISOLATED ... /CYANIDES & COPPER CMPD/
[Sax, N.I. Dangerous Properties of Industrial Materials. 4th ed. New York: Van Nostrand Reinhold, 1975. 262]**PEER REVIEWED**

Store in a cool, dry, well-ventilated location. Shelf life not to exceed 90 days or as otherwise specified by manufacturer.
[Fire Protection Guide to Hazardous Materials. 12 ed. Quincy, MA: National Fire Protection Association, 1997. ,p. 49-77]**PEER REVIEWED**

Cleanup Methods:

1. REMOVE ALL IGNITION SOURCES. 2. VENTILATE AREA OF SPILL OR LEAK. 3. IF IN GASEOUS FORM, STOP FLOW OF GAS. IF SOURCE OF LEAK IS CYLINDER & LEAK CANNOT BE STOPPED IN PLACE, REMOVE ... TO SAFE PLACE IN OPEN AIR ... REPAIR LEAK OR ALLOW CYLINDER TO EMPTY.
[Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) Publication No. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981.4]**PEER REVIEWED**

Removal of hydrogen cyanide from coal gasification effluents is discussed.
[Sato T et al; Mizu Shori Gijutsu 22 (10): 907-11 (1981)]**PEER REVIEWED**

Scrubbing of flue gases by Rectisol method is evaluated.
[Crawford KW, Orsini RA; Report: 156 pp. (1984) EPA-600/7-84-014, NTIS Order No PB84-153238]**PEER REVIEWED**

Environmental considerations - Land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liq with fly ash or cement powder. /Hydrogen cyanide, anhydrous, stabilized or hydrocyanic acid, aqueous solution or hydrogen cyanide, liquefied; hydrogen cyanide, anhydrous, stabilized; hydrogen cyanide, anhydrous, stabilized, absorbed in a porous inert material/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 582]**PEER REVIEWED**

Environmental considerations - Water spill: Use natural barriers or oil spill control booms to limit spill travel. Neutralize with agricultural lime (CaO), crushed limestone (CaCO2), or sodium bicarbonate (NaHCO3). /Hydrogen cyanide, anhydrous, stabilized or hydrocyanic acid, aqueous solution or hydrogen cyanide, liquefied; hydrogen cyanide, anhydrous, stabilized; hydrogen cyanide, anhydrous, stabilized, absorbed in a porous inert material/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 582]**PEER REVIEWED**

Environmental considerations - Air spill: Apply water spray or mist to knock down vapors. Vapors knock down water is corrosive or toxic and should be diked for containment. /Hydrogen cyanide, anhydrous, stabilized or hydrocyanic acid, aqueous solution or hydrogen cyanide, liquefied; hydrogen cyanide, anhydrous, stabilized; hydrogen cyanide, anhydrous, stabilized, absorbed in a porous inert material/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 582]**PEER REVIEWED**

REMOVAL OF COPPER, NICKEL, ZINC, CADMIUM AND CYANIDE FROM PLATING WASTEWATER BY ELECTROFLOTATION.
[POON CP C; MANAGE CONTROL HEAVY MET ENVIRON, INT CONF 572-75 (1979)]**PEER REVIEWED**

Releases may require isolation or evacuation. eliminate all ignition sources. Stop or control the leak, if this can be done without undue risk. Use vapor-suppressing foam to blanket release.
[Fire Protection Guide to Hazardous Materials. 12 ed. Quincy, MA: National Fire Protection Association, 1997. ,p. 49-77]**PEER REVIEWED**

Disposal Methods:

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number P063; D003, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.
[40 CFR 240-280, 300-306, 702-799 (7/1/96)]**PEER REVIEWED**

Rotary kiln, heat recovery boiler, reduction furnace and quench chambers are appropriate technologies for incineration of gaseous hydrogen cyanide and hydrogen gas.
[USEPA; Engineering Handbook for Hazardous Waste Incineration p.2-55 (1981) EPA 68-03-3025]**PEER REVIEWED**

Potential candidate for rotary kiln incineration, with a temperature range of 820 to 1,600 deg C and a residence time of seconds. Also, a potential candidate for fluidized bed incineration, with a temperature range of 450 to 980 deg C and a residence time of seconds. Also, a potential candidate for liquid injection incineration, with a temperature range of 650 to 1,600 deg C and a residence time of 0.1 to 2 seconds.
[USEPA; Engineering Handbook for Hazardous Waste Incineration p.3-9 (1981) EPA 68-03-3025]**PEER REVIEWED**

Occupational Exposure Standards:

OSHA Standards:

Permissible Exposure Limit: Table Z-1 8-hr Time-Weighted Avg: 10 ppm (11 mg/cu m). Skin Designation.
[29 CFR 1910.1000 (7/1/99)]**PEER REVIEWED**

Vacated 1989 OSHA PEL STEL 4.7 ppm (5 mg/cu m), skin designation, is still enforced in some states.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 365]**PEER REVIEWED**

Threshold Limit Values:

Ceiling Limit 4.7 ppm, skin
[American Conference of Governmental Industrial Hygienists. Threshold Limit Values (TLVs) for Chemical Substances and Physical Agents Biological Exposure Indices for 1999. Cincinnati, OH: ACGIH, 1999. 42]**PEER REVIEWED**

NIOSH Recommendations:

Recommended Exposure Limit: 15 Min Short-Term Exposure Limit: 4.7 ppm (5 mg/cu m). Skin.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 168]**PEER REVIEWED**

Immediately Dangerous to Life or Health:

50 ppm
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 168]**PEER REVIEWED**

Other Occupational Permissible Levels:

Inorganic cyanide standards: Bulgaria 0.3 mg/cu m; Czechoslovakia 3-15 mg/cu m; Finland 7 mg/cu m; Federal Republic of Germany 5 mg/cu m; Hungary 0.3 mg/cu m; Poland 0.3 mg/cu m; Romania 0.3 mg/cu m; USSR 0.3 mg/cu m; and Yugoslavia 5 mg/cu m. /Calcium, potassium, sodium, cyanide salts/
[NIOSH; Criteria Document: Hydrogen Cyanide and Cyanide Salts p.190 (1976) DHEW Pub. NIOSH 77-108]**PEER REVIEWED**

Emergency Response Planning Guidelines (ERPG): ERPG(1) Not appropriate; ERPG(2) 10 ppm (without serious, adverse effects) for up to 1 hr exposure; ERPG(3) 25 ppm (not life threatening) up to 1 hr exposure.
[American Industrial Hygiene Association. The AIHA 1999 Emergency Response Planning Guidelines and Workplace Environmental Exposure Level Guides Handbook. American Industrial Hygiene Association. Fairfax, VA 1999.26]**PEER REVIEWED**

Manufacturing/Use Information:

Major Uses:

/SRP: former use/ compressed gas used to exterminate rodents and insects in ships and for killing insects on trees
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 822]**PEER REVIEWED**

FUMIGANT (Former Use)
[Hayes, Wayland J., Jr. Pesticides Studied in Man. Baltimore/London: Williams and Wilkins, 1982. 126]**PEER REVIEWED**

IN METAL POLISHES, ELECTROPLATING SOLN, METALLURGICAL, & PHOTOGRAPHIC PROCESSES
[Gosselin, R.E., R.P. Smith, H.C. Hodge. Clinical Toxicology of Commercial Products. 5th ed. Baltimore: Williams and Wilkins, 1984.,p. II-113]**PEER REVIEWED**

Mfr of resin monomers, methacrylates, hexamethylenediamine, nitriles; as chem intermediate
[Clayton, G.D., F.E. Clayton (eds.) Patty's Industrial Hygiene and Toxicology. Volumes 2A, 2B, 2C, 2D, 2E, 2F: Toxicology. 4th ed. New York, NY: John Wiley & Sons Inc., 1993-1994. 3125]**PEER REVIEWED**

INT FOR METHYL METHACRYLATE, SODIUM CYANIDE, AMINOPOLYCARBOXYLIC ACID CHELATING AGENTS
[SRI]**PEER REVIEWED**

/SRP: FORMER USE/ FUMIGATION ... WITH HYDROCYANIC ACID GAS, HAS ... BEEN USED TO REDUCE BIRD POPULATIONS IN GRAIN STORAGES
[White-Stevens, R. (ed.). Pesticides in the Environment: Volume 3. New York: Marcel Dekker, Inc., 1977. 291]**PEER REVIEWED**

PRIMARILY FOR EXTERMINATING RODENTS IN FIELD BURROWS (GAS IS GENERATED BY PUTTING SODIUM CYANIDE PELLETS IN SULFURIC ACID). ... ONLY LEGITIMATE USE INDICATED TODAY SHOULD BE AS RODENTICIDE OR FUMIGANT OF SHIPS, GRAINS, & SELECTED FOODS. (FORMER USE)
[Rossoff, I.S. Handbook of Veterinary Drugs. New York: Springer Publishing Company, 1974. 267]**PEER REVIEWED**

HCN WAS USED UNDER TENTS TO CONTROL SCALE & OTHER CITRUS PESTS. ITS USE FOR THIS PURPOSE HAS BEEN DISCONTINUED BECAUSE CALIFORNIA RED SCALE DEVELOPED RESISTANCE TO GAS. (FORMER USE)
[Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980. 1203]**PEER REVIEWED**

Hydrogen cyanide is used as a starting material for nylon 66, a hexamethylenediamine-adipic acid polymer
[CHEMICAL PRODUCTS SYNOPSIS: Hydrogen Cyanide, 1983]**PEER REVIEWED**

Used to produce cyanuric acid by reacting with sodium hydroxide followed by chlorination. The product polymerizes to cyanuric chloride, a raw material for 2,4,6-s-triazine herbicides.
[CHEMICAL PRODUCTS SYNOPSIS: Hydrogen Cyanide, 1983]**PEER REVIEWED**

Used as a raw material for nitriloacids.
[CHEMICAL PRODUCTS SYNOPSIS: Hydrogen Cyanide, 1983]**PEER REVIEWED**

Hydrogen cyanide reacts with 3-(methylthio)propionaldehyde to produce 3-(methylthio)propionaldehyde cyanohydrin. This reacts with ammonia to produce 2-aminonitrile, which is hydrolysed to methionine.
[CHEMICAL PRODUCTS SYNOPSIS: Hydrogen Cyanide, 1983]**PEER REVIEWED**

Used in the manufacture of acrylates, cyanide salts, dyes, rodenticide, pesticides.
[Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 13th ed. New York, NY: John Wiley & Sons, Inc. 1997. 588]**PEER REVIEWED**

Hydrogen cyanide has been used as the instrument of execution for convicted criminals in some states of the USA primarily because of its rapid effect due to inhalation of high concn.
[USEPA; Ambient Water Quality Criteria Doc: Cyanides p.C-9 (1980) EPA 440/5-80-037]**PEER REVIEWED**

Hydrogen cyanide and its derivatives (acrylonitrile, cyanamide, cyanogen chloride, cyanides, and nitroprusside) are widely used in industry in fumigating ships and warehouses, in ore-extracting processes.
[Haddad, L.M. and Winchester, J.F. Clinical Management of Poisoning and Drug Overdosage. Philadelphia, PA: W.B. Saunders Co., 1983. 744]**PEER REVIEWED**

Hydrogen cyanide is also used in the production of synthetic fibers or plastics, and cyanide salts for extracting metals, electroplating, hardening of metals, and photography.
[World Health Organization; Early Detection of Occupational Diseases 154-164 (1986)]**PEER REVIEWED**

Manufacturers:

BP Amoco Corp., 200 East Randolph Dr., Chicago, IL 60601, (312)856-6111; Production site: Lima, OH 45802
[SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999.. 674]**PEER REVIEWED**

Cyanco Co., P.O. 1999, Winnemucca, NV 89446, (702)623-1214; Production site: Winnemucca, NV 89446
[SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999.. 674]**PEER REVIEWED**

Cytec Industries Inc., Five Garret Mountain Plaza West, Paterson, NJ 07424, (973)357-3100; Production site: Waggaman, LA 70094
[SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999.. 674]**PEER REVIEWED**

Degussa-Huls Corp., 65 Challenger Rd., Ridgefield Park, NJ 07660, (201)641-6100; Production site: Theodore, AL 36590
[SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999.. 674]**PEER REVIEWED**

Dow Chemical USA, 2030 Dow Center, Midland, MI 48674, (517)636-1000; Production site: Freeport, TX 77541
[SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999.. 674]**PEER REVIEWED**

Du Pont, 1007 Market St., Wilmington, DE 19898, (302)774-1000; Production sites: Beaumont, TX 77704; Memphis, TN 38118
[SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999.. 674]**PEER REVIEWED**

FMC Corp., 200 East Randolph Dr., Chicago, IL 60601, (312)861-6000; Production site: Green River, WY 82935
[SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999.. 674]**PEER REVIEWED**

Novartis Crop Protection Inc., 410 Swing Rd., Greensboro, NC 27409, (336)632-6000; Production site: St. Gabriel, LA 70776
[SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999.. 674]**PEER REVIEWED**

Rhone-Poulence Ag Co., 2 T.W. Alexander Dr., P.O. Box 12014, Research Triangle Park, NC 27709, (919)549-2000; Production site: Institute, WV 25112
[SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999.. 674]**PEER REVIEWED**

Rohm and Haas Texas Inc., 100 Independence Mall West, Philadelphia, PA 19106-2399, (215)592-3000; Production site: Deer Park, TX 77536
[SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999.. 674]**PEER REVIEWED**

Solutia Inc., 1030 Olive Blvd., St. Louis, MO 63141-7893, (314)674-1000; Production site: Alvin, TX 77511
[SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999.. 674]**PEER REVIEWED**

Sterling Chemicals Inc., 1200 Smith St., Suite 1900, Houston, TX 77002-4312, (713)650-3700; Production site: Texas City, TX 77590
[SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999.. 674]**PEER REVIEWED**

Methods of Manufacturing:

Prepared on large scale by catalytic oxidation of ammonia-methane mixt (Andrussow process) ... Andrussow, Angew Chem 48: 593 (1935); Maffezoni, Chim Ind (Milan) 34: 460 (1952); Faith, Keyes, & Clark's Indust Chemicals, FA Lowenheim, MK Moran, ed (Wiley-Interscience, NY, 4th ed (1975) 482-486). May also be prepd by catalytic decomp of formamide.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 822]**PEER REVIEWED**

... by recovery from coke oven gases. From bituminous coal and ammonia at 1250 deg C.
[Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 13th ed. New York, NY: John Wiley & Sons, Inc. 1997. 588]**PEER REVIEWED**

Hydrogen cyanide is produced by reacting ammonia, methane, and air over a platinum-rhodium catalyst at 1000 deg C
[CHEMICAL PRODUCTS SYNOPSIS: Hydrogen Cyanide, 1983]**PEER REVIEWED**

Produced as a co-product of acrylonitrile production via the ammoxidation of propylene
[CHEMICAL PRODUCTS SYNOPSIS: Hydrogen Cyanide, 1983]**PEER REVIEWED**

General Manufacturing Information:

... prepared in lab by acidifying NaCN or K4(Fe(CN)6): Glemser in Handbook of Preparative Inorganic Chemistry Vol 1, G Brauer, ed (Academic Press, NY, 2nd ed, 1963) pp 658-660.
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 822]**PEER REVIEWED**

The smoke exposure hazards during combustion of carbon and nitrogen containing fibers were evaluated. ... The complete combustion of 1 g polyacrylonitrile in a 15.6 l combustion chamber yielded 1500 ppm of hydrogen cyanide, much higher than from foam rubber and wool because of the presence of many CN- groups in polymer chemical structure.
[Bertol E et al; Forensic Sci Int 22 (2-3): 111-16 (1983)]**PEER REVIEWED**

Since hydrogen cyanide is highly toxic to all species in water, special attention should be given to possibility of water pollution.
[Clayton, G.D., F.E. Clayton (eds.) Patty's Industrial Hygiene and Toxicology. Volumes 2A, 2B, 2C, 2D, 2E, 2F: Toxicology. 4th ed. New York, NY: John Wiley & Sons Inc., 1993-1994. 3125]**PEER REVIEWED**

Formulations/Preparations:

Grades of purity: 96%; sometimes shipped as a water soln, or absorbed on an inert solid.
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

Grades: Technical (96-98%); 2, 5, and 10% solutions. All grades usually contain stabilizer of 0.05% phosphoric acid
[Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 13th ed. New York, NY: John Wiley & Sons, Inc. 1997. 588]**PEER REVIEWED**

Impurities:

All grades usually contain a stabilizer of 0.05% phosphoric acid.
[Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 13th ed. New York, NY: John Wiley & Sons, Inc. 1997. 588]**PEER REVIEWED**

Consumption Patterns:

62% AS AN INT FOR METHYL METHACRYLATE; 21% AS AN INT FOR CHELATING AGENTS; 10% AS AN INT FOR SODIUM CYANIDE; AND 7% IN MISC APPLICATIONS (1972)
[SRI]**PEER REVIEWED**

Adiponitrile, 38%; Methyl methacrylate, 35%; Cyanuric chloride, 10%; Chelating agents, 7%; Sodium cyanide, 5%; Nitriloacetic acid and salts, 2%; Methionine and other uses, 3% (1984)
[CHEMICAL PROFILE: Hydrogen Cyanide, 1984]**PEER REVIEWED**

CHEMICAL PROFILE: Hydrogen Cyanide. Adiponitrile (for nylon 6/6), 40%; methyl methacrylate, 30%; cyanuric chloride, 10%; chelating agents, 7%; sodium cyanide, 7%; miscellaneous, including methionine and nitriloacetic acid, 6%.
[Kavaler AR; Chemical Marketing Reporter 231 (25): 62 (1987)]**PEER REVIEWED**

CHEMICAL PROFILE: Hydrogen cyanide. Demand: 1986: 1,010 million lb; 1987: 1.030 million lb; 1991 /projected/: 1,125 million lb.
[Kavaler AR; Chemical Marketing Reporter 231 (25): 62 (1987)]**PEER REVIEWED**

Demand: (1997) 1.4 billion lbs; (1998) 1.44 billion lbs; (2002) 1.6 billion lbs
[Chemical Marketing Reporter; Chemical Profile Hydrogen Cyanide. Nov. 23, 1998 NY,NY: Schnell Pub Co (1998)]**PEER REVIEWED**

U. S. Production:

(1972) 1.23X10+11 GRAMS
[SRI]**PEER REVIEWED**

(1975) 1.37X10+11 GRAMS
[SRI]**PEER REVIEWED**

(1983) 3.0X10+11 g
[CHEMICAL PRODUCTS SYNOPSIS: Hydrogen Cyanide, 1983]**PEER REVIEWED**

(1983) 330,000 tons; (1984) 365,000 tons; (1985) 365,000 tons; (1986) 430,000 tons; (1987) 470,000 tons; (1988) 500,000 tons; (1989) 490,000 tons
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V7 761]**PEER REVIEWED**

Laboratory Methods:

Clinical Laboratory Methods:

A FLUOROMETRIC MICRODIFFUSION METHOD IS DESCRIBED FOR DETERMINING CYANIDE IN BIOLOGICAL FLUIDS. THIS DETECTION IS BASED ON THE PRODUCTION OF FLUORESCENCE BY THE TREATMENT OF CN WITH P-BENZOQUINONE. /TOTAL CYANIDE/
[MORGAN R ET AL; PROC WEST PHARMACOL SOC 19: 392-96 (1976)]**PEER REVIEWED**

CYANIDE MAY BE LIBERATED FROM BIOLOGICAL FLUIDS /BLOOD, URINE/ BY ACIDIFICATION. THE EVOLVED CYANIDE IS ABSORBED IN ALKALI AND SODIUM CYANIDE THUS FORMED IS QUANTITATIVELY DETERMINED BY MEASURING THE ABSORBANCE OF CHROMOPHORES FORMED BY INTERACTION OF THE CYANIDE ION WITH SUITABLE REAGENTS ... /ANOTHER/ PROCEDURE PRESENTS A SENSITIVE GAS CHROMATOGRAPHIC METHOD FOR DETERMINATION OF CYANIDE IN BIOLOGICAL SPECIMENTS, BASED ON ITS CONVERSION TO CYANOGEN CHLORIDE USING CHLORAMINE-T. /TOTAL CYANIDE/
[Sunshine, Irving (ed.) Methodology for Analytical Toxicology. Cleveland: CRC Press, Inc., 1975. 113]**PEER REVIEWED**

Analytic Laboratory Methods:

The separated & concentrated cyanide was determined colorimetrically. The hydrogen cyanide concn was calculated from linear calibration curves that related the determined hydrogen cyanide displacement rate or quantity of hydrogen cyanide collected to the known concn of hydrogen cyanide for standard cyanide solutions.
[Broderius SJ; Anal Chem 53 (9): 1472-7 (1981)]**PEER REVIEWED**

Hydrogen cyanide was determined in air by ion chromatography.
[Dolzine TW et al; ASTM Spec Tech Publ 786 (Toxic Mater Atmos): 142-52 (1982)]**PEER REVIEWED**

NIOSH Method 6010. Determination of hydrogen cyanide by gas chromatography with visible absorption spectrometry. Detection limit= 0.01 mg/cu m.
[U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health. NIOSH Manual of Analytical Methods. 4th ed. Methods A-Z & Supplements. Washington, DC: U.S. Government Printing Office, Aug 1994.]**PEER REVIEWED**

Colorimetric method: Pyridine-pyrazolone. /Total cyanide/
[NIOSH; Criteria Document: Hydrogen Cyanide and Cyanide Salts p.98 (1976) DHEW Pub. NIOSH 77-108]**PEER REVIEWED**

Product analysis is by titration with silver nitrate (AOAC Methods, 1984, 6.113, 6.118, 1965, 4.088-4.089, 4.093-4.094). /Hydrogen cyanide/
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium, 11 th ed., British Crop Protection Council, Surrey, England 1997 685]**PEER REVIEWED**

Sampling Procedures:

Determination in air: Sample is filtered, then drawn through a KOH-containing bubbler.
[Sittig, M. Handbook of Toxic and Hazardous Chemicals and Carcinogens, 1985. 2nd ed. Park Ridge, NJ: Noyes Data Corporation, 1985. 507]**PEER REVIEWED**

A small dosimeter of simple design can give sufficiently accurate estimates of hydrogen cyanide concn in workplace air. The proposed dosimeter is a film badge containing a strip of filter paper impregnated with palladium diacetyl dioxime. HCN reacts with the palladium complex to liberate diacetyl dioxime, which is detected by treating the paper with a solution of a nickel salt.
[Schaffernicht H; Zeitschrift fur die Gesamte Hygiene und Thre Grenzgebiete 29 (1): 17-19 (1983)]**PEER REVIEWED**

METHOD FOR DETERMINATION OF PERSONAL EXPOSURE TO HCN IS DESCRIBED. SAMPLES WERE COLLECTED BY PERMEATION THROUGH SILICONE MEMBRANE.
[HARDY JK ET AL; J ENVIRON SCI HEALTH PART A ENVIRON SCI ENG 16 (2): 201-14 (1981)]**PEER REVIEWED**

Concentrations of hydrogen cyanide in aqueous solutions were determined by bubbling compressed air through a soln to displace a small quantity of hydrogen cyanide, which was collected in a glass bead concn column or allowing HCN to diffuse from enclosed soln into dilute sodium hydroxide in a dish suspended above the soln.
[Broderius SJ; Anal Chem 53 (9): 1472-77 (1981)]**PEER REVIEWED**

Analyte: Cyanide ion; Matrix: Air; Sampler: Filter + bubbler (0.8 um cellulose ester membrane + 10 ml 0.1 N potassium hydroxide); Flow rate: 0.5 to 1 l/min; Vol: Min: 10 l @ 5 mg/cu m (as CN-), Max: 180 l @ 11 mg/cu m (as CN-); Stability: Hydrogen cyanide stable in 0.1 N potassium hydroxide at least 1 week, particulate on filter may liberate HCN gas /Cyanides, aerosol and gas/
[U.S. Department of Health and Human Services, Public Health Service. Centers for Disease Control, National Institute for Occupational Safety and Health. NIOSH Manual of Analytical Methods, 3rd ed. Volumes 1 and 2 with 1985 supplement, and revisions. Washington, DC: U.S. Government Printing Office, February 1984.p. V1 7904-1]**PEER REVIEWED**

Special References:

Special Reports:

Williams MC, James LF; Effects of herbicides on the concentration of poisonous compounds in plants: A review; Am J Vet Res 44 (12): 2420-2 (1983).

Carson BL et al; Hydrogen cyanide health effects; Report: 71 pages (1981) Iss EPA 460/3-81-026; Order No PB82-116039. A review of the health hazards associated with hydrogen cyanide.

USEPA; Ambient Water Quality Criteria Doc: Cyanides (1980) EPA 440/5-80-037

NIOSH; Criteria Document:Hydrogen Cyanide and Cyanide Salts (1976) DHEW Pub. NIOSH 77-108

Nat'l Research Council Canada; Effects of Cyanides on Aquatic Organisms with Emphasis Upon Fresh Water Fishes (1982) NRCC No.19246

DHHS/ATSDR; Toxicological Profile for Cyanide (Update) TP-92/09 (1993)

USEPA; Ambient Water Quality Criteria Doc: Cyanide (1984) EPA 440/5-84-028

World Health Organization; Early Detection of Occupational Diseases p.154-164 (1986). Occupational diseases caused by exposure to the asphyxiants carbon monoxide, hydrogen cyanide, or hydrogen sulfide were reveiwed.

Brands A; Handbook of Toxicology p.472-503 (1987). Studies into the effects of and accidental exposures to asphyxiant gases /such as hydrogen cyanide/ occurring in occupational settings are reviewed.

Paabo M, Levin BC; Govt Reports Announcements & Index (11) (1988) NTIS/PB88- 177340. The review is limited to publications in English through 1984. Carbon monoxide (CO) and hydrogen cyanide (HCN) were the predominant toxicants found among more than a hundred other gaseous products.

MATTHEWS RD; J COMBUST TOXICOL 7 (AUG): 157-72 (1980). A REVIEW WITH 51 REFERENCES FOLLOWED BY AN ESTIMATE OF THE MAX PERMISSIBLE LEVELS (MPL) OF HYDROGEN CYANIDE AND CYANOGEN CONCN IN AIR WHICH CAN BE TOLERATED BY MAN DURING LONG EXPOSURE TIMES.

Synonyms and Identifiers:

Synonyms:

AI3-31100-X
**PEER REVIEWED**

ACIDE CYANHYDRIQUE (FRENCH)
**PEER REVIEWED**

ACIDO CIANIDRICO (ITALIAN)
**PEER REVIEWED**

AERO LIQUID HCN
**PEER REVIEWED**

BLAUSAEURE (GERMAN)
**PEER REVIEWED**

BLAUWZUUR (DUTCH)
**PEER REVIEWED**

CARBON HYDRIDE NITRIDE (CHN)
**PEER REVIEWED**

Caswell No. 483
**PEER REVIEWED**

Cyaanwaterstof (Dutch)
**PEER REVIEWED**

CYANWASSERSTOFF (GERMAN)
**PEER REVIEWED**

CYCLON
**PEER REVIEWED**

CYCLONE B
**PEER REVIEWED**

CYJANOWODOR (POLISH)
**PEER REVIEWED**

EPA Pesticide Chemical Code 045801
**PEER REVIEWED**

Evercyn
**PEER REVIEWED**

FORMIC ANAMMONIDE
**PEER REVIEWED**

FORMONITRILE
**PEER REVIEWED**

HCN
**PEER REVIEWED**

HYDROCYANIC ACID
**PEER REVIEWED**

PRUSSIC ACID
**PEER REVIEWED**

ZACLONDISCOIDS
**PEER REVIEWED**

Formulations/Preparations:

Grades of purity: 96%; sometimes shipped as a water soln, or absorbed on an inert solid.
[U.S. Coast Guard, Department of Transportation. CHRIS - Hazardous Chemical Data. Volume II. Washington, D.C.: U.S. Government Printing Office, 1984-5.]**PEER REVIEWED**

Grades: Technical (96-98%); 2, 5, and 10% solutions. All grades usually contain stabilizer of 0.05% phosphoric acid
[Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 13th ed. New York, NY: John Wiley & Sons, Inc. 1997. 588]**PEER REVIEWED**

Shipping Name/ Number DOT/UN/NA/IMO:

UN 1051; Hydrogen cyanide, stabilized, cotaining less than 3% water

IMO 6.1; Hydrogen cyanide, stabilized containing 3% water; Hydrogen cyanide, solution in alcohol, with not more than 45% hydrogen cyanide; Hydrogen cyanide, aqueous solution with not more than 20% hydrogen cyanide; Hydrogen cyanide, stablilized, containing less than 3% water and absorbed in a porous inert material

UN 1614; Hydrogen cyanide, stablilized, containing less than 3% water and absorbed in a porous inert material

UN 1613; Hydrogen cyanide, aqueous solution with not more than 20% hydrogen cyanide

UN 3294; Hydrogen cyanide, solution in alcohol, with not more than 45% hydrogen cyanide

Standard Transportation Number:

49 214 17; Hydrocyanic acid solution, less than 5% hydrocyanic acid.

49 201 25; Hydrocyanic acid, liquified

49 201 30; Hydrocyanic acid, solution (5% or more hydrocyanic acid)

EPA Hazardous Waste Number:

P063; An acute hazardous waste when a discarded commercial chemical product or manufacturing chemical intermediate or an off-specification commercial chemical product or a manufacturing chemical intermediate.

D003; /SRP:/ A waste containing hydrogen cyanide may (or may not) be characterized a hazardous waste following testing for the reactivity characteristics as prescribed by the Resource Conservation and Recovery Act (RCRA) regulations.

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