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CHLORINE DIOXIDE
CASRN: 10049-04-4

See Occupational Exposure Standards

Human Health Effects:

Evidence for Carcinogenicity:

Under the current guidelines (USEPA, 1986), chlorine dioxide is classified as Group D; not classifiable as to human carcinogenicity because of inadequate data in humans and animals. Under the draft Carcinogen Assessment Guidelines (USEPA, 1996), the human carcinogenicity of chlorine dioxide cannot be determined because no satisfactory human or animal studies assessing the chronic carcinogenic potential of chlorine dioxide have been located. Concentrates prepared from drinking water treated with chlorine dioxide did not increase the incidence of lung adenomas in strain A mice, the skin tumor frequency in mice, or the incidence of gamma-glutamyl transpeptidase positive foci (a measure of preneoplastic changes) in rat livers. However, chlorine dioxide did induce a hyperplastic response in the mouse skin. Both postive and negative results have been found in genotoxicity studies. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: None.
[U.S. Environmental Protection Agency's Integrated Risk Information System (IRIS) on Chlorine Dioxide (10049-04-4) Available from: http://www.epa.gov/ngispgm3/iris on the Substance File List as of October 12, 2000]**QC REVIEWED**

Human Toxicity Excerpts:

... A CONCENTRATION OF CHLORINE DIOXIDE OF 5 PPM WAS DEFINITELY IRRITATING ... 19 PPM OF THE GAS INSIDE A BLEACH TANK WAS MORE THAN SUFFICIENT TO CAUSE THE DEATH OF 1 WORKER (TIME OF EXPOSURE NOT SPECIFIED) ... /INVESTIGATORS/ SUGGEST IN 1950 A MAXIMAL ACCEPTABLE CONCENTRATION OF 1 PPM ... FOUND CONCENTRATIONS AVERAGING ... BETWEEN TRACES AND 0.25 PPM ASSOCIATED WITH SLIGHT EFFECTS ON RESPIRATORY AILMENTS ... REPORTED BRONCHITIS AND PRONOUNCED EMPHYSEMA IN A CHEMIST AFTER REPEATEDLY EXPOSED ... SYMPTOMS WERE INCREASING DYSPNEA AND ASTHMATIC BRONCHITIS ... .
[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, 1986.118]**QC REVIEWED**

... INVESTIGATION OF WORKERS EXPOSED FOR 5 YR TO CHLORINE DIOXIDE IN SULFITE-CELLULOSE PLANT. CHLORINE ... ALSO PRESENT, AS WAS SULFUR DIOXIDE... SYMPTOMS & SIGNS OF IRRITATION OF EYES & RESPIRATORY TRACT LEADING TO SLIGHT BRONCHITIS ... IN MAJORITY ... OF WORKERS. /SOME WORKERS/ ... SHOWED IRRITATION OF GI TRACT ... .
[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, 1986.118]**QC REVIEWED**

EPIDEMIOLOGIC STUDY OF 198 PERSONS EXPOSED FOR 3 MO TO DRINKING WATER DISINFECTED WITH CHLORINE DIOXIDE WAS CONDUCTED, DATA FAILED TO IDENTIFY ANY SIGNIFICANT EXPOSURE-RELATED EFFECTS.
[MICHAEL GE ET AL; ARCH ENVIRON HEALTH 36 (1): 20-7 (1981)]**QC REVIEWED**

Two adults ingested 250 ml of chlorine dioxide in water containing concn of 40 mg/l. Within 5 min of ingestion, sudden headache, nausea, abdominal discomfort, and light-headedness were observed ... effects disappeared within 5 min.
[National Research Council. Drinking Water & Health, Volume 4. Washington, DC: National Academy Press, 1981. 174]**QC REVIEWED**

An assessment of the safety of chronically admin chlorine water disinfectants in man was conducted in 3 phases. Phase I, a rising dose tolerance investigation, examined the effects of single dose incr concn admin of disinfectants to normal healthy adult male volunteers. Phase II considered the impact on normal subjects of 12 wk daily ingestion of the disinfectants at a concn of 5 mg/l. In phase III, chlorite, at a concn of 5 mg/l, was admin daily to glucose 6-phosphate dehydrogenase (G-6-PD)-deficient subjects. The study affirmed the relative safety and tolerance of normal healthy adult males and normal healthy adult male G-6-PD-deficient individuals to daily 12 wk ingestion of 500 ml of chlorine disinfectants at a concn of 5 mg/l.
[Bianchine JR et al; Study of chlorine dioxide and its metabolites in man; Report: 100 pages (1981) ISS EPA-600/1-81-068; Order Number PB82-109356]**QC REVIEWED**

CHLORINE DIOXIDE & ITS ORG REACTION PRODUCTS MAY PRESENT A HIGHER RISK FROM ACUTE TOXICITY THAN CHLORINE, COMBINED CHLORINE, OR OZONE, BUT ITS USE MAY BE ADVANTAGEOUS WHEN THE GENERATION OF POSSIBLY CARCINOGENIC BYPRODUCTS BY OTHER DISINFECTANTS IS CONSIDERED. /SRP: THIS IS CURRENTLY A SUBJECT OF DEBATE/
[BULL RJ; J AM WATER WORKS ASSOC 72 (5): 299-303 (1980)]**QC REVIEWED**

Using records from the 1940's, the morbidity and mortality experience of infants born in a MA community using relatively high levels of chlorine dioxide for water disinfection was compared to that of infants in a suitable comparison community using conventional chlorination of water. A statistically significant pos association was found between exposure of the mother to chlorine dioxide-treated water during pregnancy and prematurity of the newborn. The rates of jaundice, birth defects and fetal and neonatal mortality did not differ significantly between communities.
[Tuthill RW et al; Environ Health Perspect 46: 39-45 (1982)]**QC REVIEWED**

Since chlorine dioxide represents an alternate method of drinking water disinfection its systematic toxicity as well as that of its disproportionation products, chlorite and chlorate, was investigated in controlled clinical studies with volunteers and with subjects exhibiting a low activity of glucose-6-phosphate dehydrogenase. At the dosages applied, no adverse health effects and no changes of any of the biochemical parameters tested could be found.
[Seiler, H.G., H. Sigel and A. Sigel (eds.). Handbook on the Toxicity of Inorganic Compounds. New York, NY: Marcel Dekker, Inc. 1988. 228]**QC REVIEWED**

Industrially men exposed to low concentrations of the gas in air have been noted occasionally to suffer from irritation of the eyes and to see haloes about lights, but these effects have been minor compared to respiratory irritation. The corneas of workers seeing haloes have not been examined to determine whether epithelial edema is present and responsible for this symptom.
[Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986. 206]**QC REVIEWED**

Irritation of the eyes and respiratory tract leading to slight bronchitis ... in workers.
[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, 1986.118]**QC REVIEWED**

A study of the blood chemistry parameters of 20 renal dialysis patients was undertaken when a local water district introduced chlorine dioxide as a disinfectant at the filtration plant headworks for 12 months without informing the renal dialysis clinic in the area of this potentially adverse change. Due to data limitations, including changes in clinical laboratories and lack of pre-exposure data for some patients, the analysis was focused on 17 patients for whom data was produced by the s clinical laboratory, for 3 months of pre-exposure and 1 month of exposure. Least-squares means of each parameter by chlorine dioxide levels of 0.0 and 1.0 mg/l at the treatment plant were adjusted for age, sex, and creatinine. Water purification at the clinic included passing the water through granular activated carbon, filtration by 5 micron filters, and the use of reverse osmosis. Chlorination products measured at the clinic after this purification and prior to preparation of the dialysate consisted only of chlorite at the 0.02-0.08 mg/l level. No evidence of chlorine dioxide induced anemia was found, nor were any other biologically significant responses observed. Study limitations include several potentially important hematologic parameters which were not measured, the small sample size, and three clinical laboratory changes.
[Ames RG, Stratton JW; Arch Environ Health 42 (5): 280-5 (1987)]**QC REVIEWED**

Workers in pulpmills can be exposed to a multitude of gases hazardous to respiratory function, the most common of which is chlorine gas. First aid reports of acute gas overexposure incidents (gassings) over an 8 year period were used to generate exposure data on a group of pulpmill workers whose respiratory function had been studied cross sectionally in 1981 and 1988. Three hundred forty eight incidents representing 174 workers were identified, 78% of these being treated solely by the first aid attendant with the administration of O2 and cough suppression medication. Among 316 workers tested during a 1988 respiratory health survey, 78 had at least one chlorine or chlorine dioxide gassing incident. There was a significant decrease in the FEV1/FVC ratio (p <0.05) as well as increased risk for workplace associated chest symptoms in this group with at least one gassing incident. In an age and smoking matched analysis, among workers tested both in 1981 and 1988, there was a greater decline in FEV1/FVC ratio and MMF (p <0.05) in the gassed group than in the nonexposed group over the 7 year period of observation. These results emphasize the need for worker protection against accidental chlorine gas exposures.
[Salisbury DA et al; Am J Ind Med 20 (1): 71-82 (1991)]**QC REVIEWED**

A womangardener of 49 years of age suffered an inhalational intoxication from chlorine dioxide while bleaching dried flowers. Preparation of the bleaching solutions was associated with a sharp pungent smell, coughing, pharyngeal irritation and headache. Seven hours later increasing cough and dyspnea led to hospitalisation. Clinical findings were tachypnoea, tachycardia, and rales of auscultation; clinical chemistry revealed marked leucocytosis. Chest X-ray did not yield any abnormal findings. Initially the vital capacity and forced expiratory volume in 1 sec markedly reduced and the resistance correspondingly enhanced. Blood gas analysis showed hypoxemia despite alveolar hyperventilation. Administration of corticosteroids resulted in significant alleviation of complaints and in improved lung function with stabilization in a highly normal range, as confirmed by follow-up examination two years later. The chlorine dioxide intoxication had been due to pH level reduction resulting from an incorrect proportioning and handling of the individual bleaching agent components when preparing the solution.
[Exner-Freisfeld H et al; Dtsch Med Wochenschr 111 (50): 1927-30 (1986)]**QC REVIEWED**

Human Toxicity Values:

... A CONCENTRATION OF CHLORINE DIOXIDE OF 5 PPM WAS DEFINITELY IRRITATING ... 19 PPM OF THE GAS INSIDE A BLEACH TANK WAS MORE THAN SUFFICIENT TO CAUSE THE DEATH OF 1 WORKER (TIME OF EXPOSURE NOT SPECIFIED) ... .
[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, 1986.118]**QC REVIEWED**

Skin, Eye and Respiratory Irritations:

MAY BE HIGHLY IRRITATING TO SKIN AND MUCOUS MEMBRANES OF RESPIRATORY TRACT. ...
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

... Irritation of the eyes ... respiratory irritation.
[Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986. 206]**QC REVIEWED**

May cause irritation of the eyes, nose, & throat. ...
[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.]**QC REVIEWED**

Medical Surveillance:

Protect/ from exposure those individuals with pulmonary diseases.
[ITII. Toxic and Hazardous Industrial Chemicals Safety Manual. Tokyo, Japan: The International Technical Information Institute, 1988. 115]**QC REVIEWED**

Emergency Medical Treatment:

Emergency Medical Treatment:

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The following Overview, *** CHLORINE GAS ***, is relevant for this HSDB record chemical.

Life Support:
  o   This overview assumes that basic life support measures
      have been instituted.
Clinical Effects:
  SUMMARY OF EXPOSURE
   0.2.1.1 ACUTE EXPOSURE
     o   Inhalation is the main route of chlorine gas exposure.
         Chlorine gas vapors are heavy and settle in low areas;
         odor is not a good indicator of exposure severity.
         Chlorine gas is severely irritating on contact and can
         be corrosive to the eyes, skin, nose, throat, and
         mucous membranes; exposure can result in severe or
         permanent eye injury.  Contact with the escaping
         compressed liquid can cause frostbite and/or chemical
         burns to the eyes and skin.  Chlorine combines with
         tissue water to produce HCl, producing injury and
         reactive oxygen species.
     o   Mixing household cleaning agents (bleach with acids or
         ammonia) produces chlorine gas and other active
         chlorine compounds such as chloramine.  For example,
         mixing household bleach (sodium hypochlorite) with acid
         toilet bowl cleaners produces chlorine gas.  Ammonia
         mixed with bleach results in the release of chloramine.
         A single acute exposure to these reaction products
         commonly produces coughing, lacrimation,
         conjunctivitis, a burning sensation in the chest,
         pneumonitis, and tachycardia.  A few patients may
         experience vomiting, diaphoresis and headache.  Severe
         cases may result in noncardiogenic pulmonary edema.
     o   Exposure to chlorine gas at an air concentration of 1
         to 3 ppm produces mild irritation; 3 to 6 ppm, itching,
         stinging and burning of the eyes, lacrimation,
         blepharospasm, as well as burning of the nose and
         throat, sneezing, coughing, and bloody nose or sputum;
         5 to 10 ppm, moderate upper respiratory irritation; 10
         to 20 ppm, intense irritation; 30 ppm, chest pain,
         vomiting, dyspnea and cough.
     o   More severe exposures produce more serious effects.
         For example, 14 ppm for 30 minutes results in severe
         pulmonary damage; 430 ppm or more for 30 minutes, or 34
         to 51 ppm for 60 minutes may be fatal; and 1,000 ppm
         can be fatal within a few breaths.
     o   Symptoms of exposure to chlorine gas also include
         rhinorrhea, nausea, headache, dizziness and syncope,
         muscle weakness, choking (cramps in the pharyngeal
         muscles), epigastric pain, a feeling of suffocation,
         apprehension and anxiety, dermatitis, retrosternal
         burning and substernal pain, respiratory distress,
         shortness of breath, pneumonia, bronchospasm and
         noncardiogenic pulmonary edema.  Bronchopneumonia or
         respiratory collapse may be lethal complications.
     o   Hypoxia is common, whereas C02 retention and pulmonary
         function abnormalities are generally less common.
         Rales, hypoxemia and airway obstruction have been
         found.
     o   Respiratory symptoms may be immediate or delayed up to
         several hours after exposure.  Symptoms generally
         resolve within 6 hours after mild exposures, but may
         continue for more than 24 hours after severe exposures.
         Deterioration may continue for several hours.
     o   Moderate or severe exposure (associated with acute
         marked airflow obstruction and air-trapping) often
         results in residual pulmonary dysfunction, most notably
         hyperreactive airways and low residual volumes.  These
         long-term sequelae of acute exposure may persist for
         several years.
     o   Chronic exposure to chlorine gas may cause dyspnea,
         palpitations, chest pain, reactive upper airways
         dysfunction syndrome, tooth corrosion, and an increased
         prevalence of colds.  Chronic exposure to 15 ppm
         produced coughing, hemoptysis, chest pain and sore
         throat.  Chronic exposure to chlorine gas is the most
         frequent cause of occupational asthma.
  VITAL SIGNS
   0.2.3.1 ACUTE EXPOSURE
     o   Tachycardia and tachypnea are common.  Severe exposure
         may cause cardiovascular collapse and respiratory
         arrest.
  HEENT
   0.2.4.1 ACUTE EXPOSURE
     o   Green hair, dental enamel erosion, conjunctivitis,
         lacrimation, nasal and throat irritation may occur.
         Anosmia is reported.
  CARDIOVASCULAR
   0.2.5.1 ACUTE EXPOSURE
     o   Tachycardia and initial hypertension followed by
         hypotension may occur.  Cardiovascular collapse may
         ensue following severe exposure.
  RESPIRATORY
   0.2.6.1 ACUTE EXPOSURE
     o   Feeling of burning and suffocation, coughing, choking,
         laryngeal edema, bronchospasm, and hypoxia may occur.
         In high concentrations, syncope and almost immediate
         death may occur.  Pulmonary edema is common after
         severe exposure.
     o   Multiple exposures produced flu-like symptoms and high
         risk of developing reactive airway dysfunction
         syndrome.
     o   Persistent pulmonary dysfunction has been reported in
         some individuals following severe inhalational
         exposure.
  NEUROLOGIC
   0.2.7.1 ACUTE EXPOSURE
     o   Headache may develop.  Agitation and anxiety may
         develop in patients with significant respiratory
         compromise.
  GASTROINTESTINAL
   0.2.8.1 ACUTE EXPOSURE
     o   Vomiting may occur following initial exposure.
  ACID-BASE
   0.2.11.1 ACUTE EXPOSURE
     o   Following severe exposure, metabolic acidosis secondary
         to hypoxemia may be noted.
  DERMATOLOGIC
   0.2.14.1 ACUTE EXPOSURE
     o   Dermal exposure may cause erythema, pain, irritation,
         and cutaneous burns.
  REPRODUCTIVE HAZARDS
    o   Chlorine (as hypochlorite) has been teratogenic in
        experimental animals.  Mutations were detected using
        sperm morphology in mouse studies.
  CARCINOGENICITY
   0.2.21.2 HUMAN OVERVIEW
     o   Lymphoma has been observed in relation to water
         treatment with chlorine.  Associations with increased
         renal, bladder and gastric cancers have also been found
         but firm conclusions cannot be drawn because of mixed
         exposures with caustic acids.
   0.2.21.3 ANIMAL OVERVIEW
     o   Chlorine gas was not carcinogenic in mice and rats
         exposed to varying concentrations.  Chlorine
         administered in drinking water produced lymphomas
         and/or leukemia in rats, but was not carcinogenic in a
         third study.
  GENOTOXICITY
    o   Haloacetonitriles have produced DNA strand breaks in
        cultured human cells.  Mutations have been detected in S
        typhimurium and chromosome aberrations have been
        detected in human lymphocytes.
Laboratory:
  o   Chlorine blood concentrations are not clinically useful.
      No specific lab work (CBC, electrolytes, urinalysis) is
      needed unless  otherwise indicated.
  o   Monitor arterial blood gases and/or pulse oximetry, chest
      radiograph,  and pulmonary function tests in patients with
      respiratory symptoms.
Treatment Overview:
  INHALATION EXPOSURE
    o   Rescuers should wear self-contained breathing apparatus
        (SCBA) and have protective clothing, if needed.
    o   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
        beta2  agonist and corticosteroid aerosols.
    o   ADMINISTER HUMIDIFIED OXYGEN if the patient has
        respiratory effects.  Nebulized 5% sodium bicarbonate
        has been anecdotally reported to result in dramatic
        improvement, but is not routinely recommended due to a
        lack of studies showing safety and efficacy.
    o   OBTAIN BASELINE CHEST X-RAY if symptomatic.
    o   MONITOR RESPIRATORY FUNCTION for 24 hours to assure that
        pulmonary edema does not develop.  Pulmonary edema may
        be delayed.
    o   EXAMINE MUCOUS MEMBRANES, eyes and skin to be certain
        that corrosive effects have not occurred.
    o   AIRWAY MANAGEMENT - Manage airway aggressively in
        patients with evidence of upper airway burns or edema.
    o   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.
    o   BRONCHOSPASM - treat with inhaled beta adrenergic
        agonists.
    o   STEROIDS - Steroid therapy may be useful, however
        conclusive efficacy data is lacking.
  EYE EXPOSURE
    o   DECONTAMINATION:  Irrigate exposed eyes with copious
        amounts of tepid water for at least 15 minutes.  If
        irritation, pain, swelling, lacrimation, or photophobia
        persist, the patient should be seen in a health care
        facility.
  DERMAL EXPOSURE
    o   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.                                
Range of Toxicity:
  o   In concentrations at or below the threshold limit value of
      1 ppm (more than what is usually generated in home
      accidents) only minimal findings will occur.  Immediately
      dangerous to life and health (NIOSH IDLH) 10 ppm.
  o   Exposure to industrial strength chlorine gas results in
      more significant symptomology, including severe pulmonary
      irritation; pulmonary edema; skin, mucous membrane, and
      eye corrosion.  Death may be rapid.
  o   One or two breaths of gas accumulating above swimming pool
      or spa chlorinator tablets may cause marked respiratory
      distress and hypoxemia.         

[Rumack BH: POISINDEX(R) Information System. Micromedex, Inc., Englewood, CO, 2003; CCIS Volume 116, edition exp May, 2003. Hall AH & Rumack BH (Eds): TOMES(R) Information System. Micromedex, Inc., Englewood, CO, 2003; CCIS Volume 116, edition exp May, 2003.]**PEER REVIEWED**

Animal Toxicity Studies:

Evidence for Carcinogenicity:

Under the current guidelines (USEPA, 1986), chlorine dioxide is classified as Group D; not classifiable as to human carcinogenicity because of inadequate data in humans and animals. Under the draft Carcinogen Assessment Guidelines (USEPA, 1996), the human carcinogenicity of chlorine dioxide cannot be determined because no satisfactory human or animal studies assessing the chronic carcinogenic potential of chlorine dioxide have been located. Concentrates prepared from drinking water treated with chlorine dioxide did not increase the incidence of lung adenomas in strain A mice, the skin tumor frequency in mice, or the incidence of gamma-glutamyl transpeptidase positive foci (a measure of preneoplastic changes) in rat livers. However, chlorine dioxide did induce a hyperplastic response in the mouse skin. Both postive and negative results have been found in genotoxicity studies. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: None.
[U.S. Environmental Protection Agency's Integrated Risk Information System (IRIS) on Chlorine Dioxide (10049-04-4) Available from: http://www.epa.gov/ngispgm3/iris on the Substance File List as of October 12, 2000]**QC REVIEWED**

Non-Human Toxicity Excerpts:

... CONCENTRATIONS APPROXIMATING 0.1 PPM CHLORINE DIOXIDE ... NO ABNORMAL REACTION IN RATS EXPOSED ... /FOR 10 WEEKS AT 5 HR/DAY/.
[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, 1986.118]**QC REVIEWED**

A 90 DAY STUDY EXAMINED EFFECTS OF 20 PPM (2 MG/KG/DAY) & 200 PPM (9 MG/KG/DAY) OF CHLORINE DIOXIDE IN DRINKING WATER OF AFRICAN GREEN MONKEYS. MINIMAL LOCAL IRRITATION OF ORAL MUCOSA WAS OBSERVED ... PRELIMINARY REPORTS STATE THAT NO MEASURABLE TOXICITY TO HEMATOPOIETIC SYSTEM OR OTHER SYSTEMS WAS OBSERVED ... .
[National Research Council. Drinking Water and Health. Volume 3. Washington, DC: National Academy Press, 1980. 195]**QC REVIEWED**

Subchronic toxicity of chlorine dioxide was studied in the African green monkey by admin in drinking water during 30-60 days rising dose protocols. Thyroid metab was inhibited in animals at approx 9.0 mg/kg/day. A significant decr of serum thyroxine occurred after the 4th wk of exposure to 100 mg/l. The extent of thyroid suppression was dose-dependent and reversible. The selective thyroid effect of chlorine dioxide was unexplained and paradoxical, since it was rapidly reduced by oral and gastric secretions to nonoxidizing species (presumably Cl-).
[Bercz JP et al; Environ Health Perspect 46: 47-55 (1982)]**QC REVIEWED**

IN A 2 YEAR STUDY, RATS EXPOSED TO CHLORINE DIOXIDE IN THEIR DRINKING WATER SHOWED NO ADVERSE EFFECTS AFTER CONSUMING 1.1 MG/KG/DAY, BUT THOSE DRINKING 11 MG/KG/DAY SHOWED A HIGHER MORTALITY BY THE END OF THE STUDY ... .
[National Research Council. Drinking Water and Health. Volume 3. Washington, DC: National Academy Press, 1980. 195]**QC REVIEWED**

EXPOSURE OF A/J (HIGH GLUCOSE-6-PHOSPHATE DEHYDROGENASE DEFICIENCY) & C57L/J (LOW GLUCOSE-6-PHOSPHATE DEHYDROGENASE DEFICIENCY) LAB MICE TO 100 PPM CHLORINE DIOXIDE IN THEIR DRINKING WATER FOR 30 DAYS PRODUCED NO CHANGES IN 11 HEMATOLOGICAL PARAMETERS. /SRP: THESE DATA SHOW THAT GLUCOSE-6-PHOSPHATE DEHYDROGENASE DEFICIENCY DOES NOT PREDISPOSE TO SPECIAL SENSITIVITY/
[MOORE GS, CALABRESE EJ; J ENVIRON PATHOL TOXICOL 4 (2-3): 513-24 (1980)]**QC REVIEWED**

AQ CHLORINATION OF CATECHOL (4 & 8 MMOL) AT VARYING REAGENT RATIOS WAS SHOWN TO PRODUCE HIGH MUTAGENICITY WITH THE AMES SALMONELLA STRAIN TA100. THE MUTAGENICITY PEAKS AT 3 EQUIV CHLORINE/MOL OF CATECHOL. IF THE CHLORINE IS REPLACED WITH EQUIV CHLORINE DIOXIDE VERY LITTLE MUTAGENICITY IS PRODUCED.
[NAZAR MA ET AL; MUTAT RES 89 (1): 45-56 (1981)]**QC REVIEWED**

CHLORINE DIOXIDE (1, 10, 100 PPM) GIVEN DAILY IN DRINKING WATER DECR BLOOD GLUTATHIONE, DECR OSMOTIC FRAGILITY, & CHANGED MORPHOLOGY OF ERYTHROCYTES IN BOTH CHICKENS & RATS AFTER TWO MO.
[ABDEL-RAHMAN MS, COURI D; J ENVIRON PATHOL TOXICOL 3 (1-2): 431-49 (1979)]**QC REVIEWED**

The study was conducted to examine the effects of chlorine dioxide and its metabolites on the formation of chloroform, tritiated thymidine incorporation in organs and hepatic microsomal enzyme activities in rats. Male rats were admin 0, 10, or 100 mg/l chlorine dioxide daily for 1 yr in drinking water. Blood chloroform levels were significantly decr after 2, 10, and 12 mo of treatment. No differences in chloroform values in liver, kidney, spleen, testes, and brain were observed. Chlorine dioxide admin in drinking water for 3 wk inhibited the incorporation of (3)H-thymidine into nuclei of rat testes and small intestine. The incorporation in the liver was incr in 10 and 100 mg/l chlorine dioxide groups. Alanine hydroxylase activity was incr in the 100 mg/l chlorine dioxide group and hexobarbital sleep time studies showed slight decr in the chlorine dioxide treatment groups after 1 yr of treatment.
[Suh DH et al; Arch Environ Contam Toxicol 13 (2): 163-9 (1984)]**QC REVIEWED**

Female rats were admin chlorine dioxide at 0, 1, 10, and 100 mg/l daily in the drinking water for 2.5 mo prior to and throughout gestation. A significant dose-response relation in the decr of the numbers of implants and live fetuses was observed. Fetal wt was significantly incr in the 100 mg/l group. Skeletal defects, such as incompletely ossified or missing sternebrae, rudimentary ribs, and incompletely ossified skull bones were not significantly different from controls. A few cases of hypoplastic kidney, hydronephrosis, and dextrocardia were observed.
[Suh DH et al; J Appl Toxicol 3 (2): 75-9 (1983)]**QC REVIEWED**

The toxicity of chlorine dioxide (0, 1, 10, 100, 1000 mg/l) was studied in rats. After 9 mo treatment, the osmotic fragility of red blood cells was decr in all groups. After 9 mo, erythrocyte counts, hematocrit, and hemoglobin were decr in all groups. Chlorine dioxide admin in drinking water for 3 mo inhibited the incorporation of (3)H-thymidine into nuclei of rat testes. This inhibition was observed in the kidney of rats treated with 100 mg chlorine dioxide/l. The incorporation in small intestinal nuclei was incr in rats treated with both 10 and 100 mg chlorine dioxide/l. Body wt was decr after 10 and 11 mo treatment.
[Abdel-Rahman MS et al; J Am Coll Toxicol 3 (4): 277-84 (1984)]**QC REVIEWED**

The incr of direct-acting mutagens after treatment of stored water of the Rivers Rhine and Meuse with chlorine dioxide was similar to the mutagenic effect demonstrated after chlorination. An incr of mutagenicity in Salmonella typhimurium TA 98 after disinfection of water was always more pronounced without metabolic activation than with metabolic activation.
[Zoeteman BC J et al; Environ Health Perspect 46: 197-225 (1982)]**QC REVIEWED**

Giant kelp (Macrocystis pyrifera) spores were exposed in beakers to a 25% solution of chlorine dioxide at concentrations ranging from 2.5 ug/l to 250 mg/l for 48 hr at 15 deg C. Germination of M pyrifera was significantly reduced at chlorine dioxide concentrations of 25 and 250 mg/l. At the highest dose, germination was decr by about 80%. Germ tube length was significantly reduced only at 250 mg/l.
[Hose JE et al; Bull Environ Contam Toxicol 42 (3): 315-9 (1989)]**QC REVIEWED**

Purple sea urchin (Strongylocentrotus purpuratus) embryos were exposed in beakers to a 25% solution of chlorine dioxide at concentrations ranging from 2.5 ug/l to 250 mg/l for 48 hr at 15 deg C. Developmental abnormalities in the sea urchin embryos were determined by Sedgewick-Rafter counting; abnormalities were grouped into one of five categories: pre-hatch malformations, retarded development, post-hatch malformations, skeletal malformations and gut malformations. Developmental abnormalities in the sea urchin were evident only at exposure to the highest chlorine dioxide concentration tested, 250 mg/l. Compared with the control, pre-hatch malformations were 6% higher; retarded development, 2%; post-hatch malformations, 20%; skeletal malformations, 21%; and gut malformations, 11%.
[Hose JE et al; Bull Environ Contam Toxicol 42 (3): 315-9 (1989)]**QC REVIEWED**

Kelp bass (Serranidae: Paralabrax clathratus) 20 hr old eggs were maintained at 20 deg C without aeration in beakers containing chlorine dioxide at concentrations ranging from 2.5 ug/l to 25 mg/l. Hatching occurred 40 hr post fertilization, and after 48 hr exposure in the test solutions, dead eggs and larvae and surviving larvae were counted using a dissecting microscope. Survival of larval kelp bass was not significantly affected by chlorine dioxide.
[Hose JE et al; Bull Environ Contam Toxicol 42 (3): 315-9 (1989)]**QC REVIEWED**

Non-volatile reaction products generated from the reactions of 70 mM aqueous chlorine or chlorine dioxide with 10 mM L-tryptophan were shown to be direct acting mutagens to Salmonella typhimurium TA100 and TA98. Several of the fluorescent bands obtained after thin-layer chromatographic fractionation of the XAD-2/8 resin concentrates of the reaction mixtures were shown to be more mutagenic than the reaction mixtures using the Ames Salmonella/microsome assay. In addition, these fractions were shown to be capable of increasing significantly the frequency of sister chromatid exchange in Chinese hamster ovary cells in the absence of rat liver S9 mix. GC/MS analysis of the products in a highly mutagenic fraction of the aqueous chlorine reaction products identified 1,1,3-trichloropropanone, 1,1,3,3-tetrachloropropanone and dichloroquinoline.
[Owusu-Yaw J et al; Toxicol Lett (AMST); 56 (1-2): 213-28 (1991)]**QC REVIEWED**

A total of 47 chemical substances including 32 synthetic food additives, seven additives from natural sources, three trihalogenated methanes, two fluoro-compounds for dental use, one insecticide, and two other compounds were subjected to the micronucleus test in mice. Five compounds, ie, chlorine dioxide, maltol, potassium bromate, sodium chlorite and sodium dehydroacetate, were found to induce micronuclei after a single ip injection. Potassium bromate, sodium chlorite and sodium dehydroacetate were tested further by oral administration, and potassium bromate showed a clearly positive result.
[Hayashi M et al; Food Chem Toxicol 26 (6): 487-500 (1988)]**QC REVIEWED**

Toxicological studies dealing with recent findings of health effects of drinking water disinfectants are reviewed. Experiments with monkeys and rodents indicate that the biological activity of ingested disinfectants is expressed via their chemical interaction with the mucosal epithelia, secretory products, and nutritional contents of the alimentary tract. Evidence exists that a principal partner of this redox interaction is the iodide of nutritional origin that is ubiquitous in the gastrointestinal tract. Thus the observation that subchronic exposure to chlorine dioxide in drinking water decreases serum thyroxine levels in mammalian species can be best explained with changes produced in the chemical form of the bioavailable iodide. Ongoing and previously reported mechanistic studies indicate that oxidizing agents such as chlorine-based disinfectants oxidize the basal iodide content of the gastrointestinal tract. The resulting reactive iodine species readily attaches to organic matter by covalent bonding. Evidence suggests that the extent to which such iodinated organics are formed is proportional to the magnitude of the electromotive force and stoichiometry of the redox couple between iodide and the disinfectant. Because the extent of thyroid uptake of the bioavailable iodide does not decrease during chlorine dioxide ingestion, it seems that chlorine dioxide does not cause iodide deficiency of sufficient magnitude to account for the decrease in hormonogenesis. Absorption of one or more of iodinated molecules, eg, nutrients, hormones, or cellular constituents of the alimentary tract having thyromimetic or thyroid inhibitory properties, is a better hypothesis for the effects seen.
[Bercz JP et al; Environ Health Perspect 69: 249-54 (1986)]**QC REVIEWED**

Female SENCAR mice were treated with aqueous solutions of hypochlorous acid, sodium hypochlorite, chlorine dioxide, and monochloramine by whole body exposure (except head) for a 10 min period for 4 days in the first experiment and for 1 day (except NH2Cl) in the second experiment. Animals were sacrificed the day following the last treatment (experiment 1) or on day 1, 2, 3, 4, 5, 8, 10, and 12 following treatment (experiment 2), and skin thickness was measured by light microscopy at X400 by use of an eyepiece micrometer. Concentrations of disinfectants were 1, 10, 100, 300, and 1000 mg/l, for experiment 1 and 1000 mg/l for experiment 2. Thickness of the interfollicular epidermis for control animals was 15.4 + or - 1.5 micron. After 4 days of treatment at 1000 mg/l, hypochlorous acid and chlorine dioxide increased thickness to 39 + or - 7.0 and 40.2 + or - 11.8, and sodium hypochlorite increased thickness to 25.2 + or - 6.1 micron. Only hypochlorous acid and chlorine dioxide were tested at 300 mg/L, yielding an interfollicular epidermis thickness of 30.0 + or - 13.1 and 16.8 + or - 0.8 micron, respectively. The response to HOCl was found to be dose related; the minimally effective dose was 100 mg/l. In earlier, preliminary tests to determine optimum treatment schedule, the response to hypochlorous acid appeared to be maximal after 4 days of treatment and tended to decrease with further treatment. The time-course study following a single treatment of 1000 mg/l hypochlorous acid, however, showed a progression of interfollicular epidermis thickening of from 18.3 + or - 1.4 at 1 day to 30.8 + or - 8.0 at 8 days, decreasing to 19.1 + or - 6.2 micron at 12 days.
[Robinson M et al; Environ Health Perspect; 69: 293-300 (1986)]**QC REVIEWED**

Ecotoxicity Values:

LC50 Fathead minnow juvenile flow through 0.02 mg/l/96 hr
[Wilde EW et al; Water Res 17 (10): 1327-32 (1983)]**QC REVIEWED**

LC50 Fathead minnow adult 0.17 mg/l/96 hr /Conditions of bioassay not specified/
[Wilde EW et al; Water Res 17 (10): 1327-32 (1983)]**QC REVIEWED**

LC50 Bluegill young of the year 0.15 mg/l/96 hr /Conditions of bioassay not specified/
[Wilde EW et al; Water Res 17 (10): 1327-32 (1983)]**QC REVIEWED**

Metabolism/Pharmacokinetics:

Absorption, Distribution & Excretion:

Chlorine dioxide is rapidly absorbed after oral admin, and plasma levels peak within 1 hr after dosing. 43% of admin dose was excreted in urine and feces within 72 hr. None was detected in expired air. The plasma half-life was ... 44 hr in rats.
[National Research Council. Drinking Water & Health, Volume 4. Washington, DC: National Academy Press, 1981. 174]**QC REVIEWED**

After oral admin of Alcide (chlorine dioxide) in rats, the peak plasma level was obtained in 8 hr. At 144 hr, radioactivity was highest in plasma followed by lung, kidney, skin, bone marrow, stomach, ovary, duodenum, ileum, spleen, fat, brain, liver, and carcass. Subcellular distribution revealed that 85% of the activity in the liver homogenate resided in the cytosol. 70% of total activity in plasma was located in the trichloroacetic acid supernatant, with 30% bound to the precipitated protein fraction. Urinary excretion accounted for most of the (36)chlorine eliminated. Radioactivity was excreted as chlorine(-) and chlorine dioxide(-) in urine.
[Scatina J et al; J Appl Toxicol 3 (3): 150-3 (1983)]**QC REVIEWED**

Chlorine dioxide ... may be absorbed by ingestion as well as inhalation.
[Seiler, H.G., H. Sigel and A. Sigel (eds.). Handbook on the Toxicity of Inorganic Compounds. New York, NY: Marcel Dekker, Inc. 1988. 228]**QC REVIEWED**

Biological Half-Life:

After oral admin of Alcide (chlorine dioxide) in rats, the peak plasma level was obtained in 8 hr. The half-life for (36)Cl absorption from plasma was 8.03 hr, while the half life for (36)Cl elimination from plasma was 48.02 hr.
[Scatina J et al; J Appl Toxicol 3 (3): 150-3 (1983)]**QC REVIEWED**

Pharmacology:

Environmental Fate & Exposure:

Environmental Fate:

HYDROGEN PEROXIDE (H2O2), CHLORITE, CHLORATE, CL2O3, OXYGEN (O2), & CHLORINE HAVE ALL BEEN REPORTED AS INTERMEDIATES OR PRODUCTS /OF CHLORINE DIOXIDE BREAKDOWN/. PRESUMABLY CHLORINE DIOXIDE WILL NOT PERSIST IN OPEN BASINS OR RESERVOIRS, ALTHOUGH IT CAN REMAIN FOR DAYS IN CLEAN DISTRIBUTION SYSTEMS.
[National Research Council. Drinking Water and Health. Volume 2. Washington, DC: National Academy Press, 1980. 193]**QC REVIEWED**

IT IS GENERALLY ACCEPTED THAT THE PREDOMINANT REACTION PRODUCT OF CHLORINE DIOXIDE IN WATER TREATMENT IS CHLORITE & THAT CHLORATE & OTHER IONS ARE PRODUCED IN MINOR AMOUNTS ... AN APPROXIMATELY 50% CONVERSION OF CHLORINE DIOXIDE TO CHLORITE WAS REPORTED ... /IN/ WATER CONTAINING NATURAL HUMIC ACIDS.
[National Research Council. Drinking Water and Health. Volume 3. Washington, DC: National Academy Press, 1980. 195]**QC REVIEWED**

CHLORINE DIOXIDE DOES NOT CAUSE FORMATION OF TRIHALOMETHANES, DOES NOT REACT WITH AMMONIA, & DOES NOT CAUSE FORMATION OF CHLORAMINES. IT CAN ... DISPROPORTIONATE TO CHLORATE & CHLORITE ... BY RAISING PH TO 11 OR 12 ... THIS IS NOT BELIEVED TO BE AN IMPORTANT REACTION IN WATER UNDERGOING TREATMENT.
[National Research Council. Drinking Water and Health. Volume 3. Washington, DC: National Academy Press, 1980. 194]**QC REVIEWED**

/PRODUCTS FORMED DURING OXIDATIVE TREATMENT OF WATER/: BOTH OXYGENATED & CHLORINATED PRODUCTS MAY BE FORMED, THE LATTER BEING FOUND MOST PROMINENTLY IN CONNECTION WITH REACTIONS OF PHENOLIC SUBSTANCES. OTHER PRODUCTS THAT MIGHT AFFECT HEALTH ARE QUINONES & 1,2-EPOXY COMPOUNDS.
[National Research Council. Drinking Water and Health. Volume 2. Washington, DC: National Academy Press, 1980. 199]**QC REVIEWED**

Environmental Abiotic Degradation:

SINCE CHLORITE IS FORMED AT A RATE OF 50% OF THE CHLORINE DIOXIDE DEMAND, SERIOUS CONSIDERATION MUST BE GIVEN TO LIMITING CHLORITE FORMATION BEFORE CHLORINE DIOXIDE IS ADOPTED AS DISINFECTANT TO REPLACE CHLORINE.
[MOORE GS, CALABRESE EJ; J ENVIRON PATHOL TOXICOL 4 (2-3) 513 (1980)]**QC REVIEWED**

Environmental Water Concentrations:

PROPOSED LIMITS OF USE OF CHLORINE DIOXIDE WERE BASED PRIMARILY UPON ASSESSMENT OF HAZARDS OF RESIDUAL CHLORITE. CONCERNED WITH POSSIBLE IN-VIVO METHEMOGLOBIN PRODUCTION BY CHLORITE ... RECOMMENDED THAT NO CHLORITE REACH THE DISTRIBUTION POINT.
[National Research Council. Drinking Water and Health. Volume 3. Washington, DC: National Academy Press, 1980. 195]**QC REVIEWED**

Environmental Standards & Regulations:

FIFRA Requirements:

Ninety days after publication of this notice ingredients /incl chlorine dioxide/ ... will be removed from Reregistration List D, and all associated registrations will be cancelled ... .
[56 FR 50425 (10/4/91)]**QC REVIEWED**

Acceptable Daily Intakes:

... One may calculate the 24 hr SNARL /suggested no adverse response level/ as ... 1.2 mg/l.
[National Research Council. Drinking Water & Health, Volume 4. Washington, DC: National Academy Press, 1981. 177]**QC REVIEWED**

7-Day exposure: ... One may calculate the SNARL /suggested no adverse response level/ as ... 0.125 mg/l.
[National Research Council. Drinking Water & Health, Volume 4. Washington, DC: National Academy Press, 1981. 178]**QC REVIEWED**

Federal Drinking Water Standards:

EPA 800 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**

Federal Drinking Water Guidelines:

EPA 800 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**

State Drinking Water Guidelines:

(ME) MAINE 60 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**

Chemical/Physical Properties:

Molecular Formula:

Cl-O2
**QC REVIEWED**

Molecular Weight:

67.46
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

Color/Form:

YELLOW TO REDDISH-YELLOW GAS AT ROOM TEMP
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

SOLID CHLORINE DIOXIDE IS A YELLOWISH-RED CRYSTALLINE MASS; LIQUID IS REDDISH-BROWN
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

Yellow to red gas or a red-brown liquid (below 52 degrees F) ...
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 58]**QC REVIEWED**

Odor:

UNPLEASANT ODOR SIMILAR TO CHLORINE AND NITRIC ACID
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

... Unpleasant odor similar to chlorine and nitric acid.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 58]**QC REVIEWED**

Boiling Point:

11 DEG C
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

Melting Point:

-59 DEG C
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

Density/Specific Gravity:

1.642 @ 0 DEG C (LIQ)
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

Solubilities:

IN WATER 3.01 G/L AT 25 DEG C AND AT 34.5 MM HG
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

SOL IN ALKALINE AND SULFURIC ACID SOLN
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

2000 CC (GAS) IN 100 CC COLD WATER
[Lide, D.R. (ed). CRC Handbook of Chemistry and Physics. 72nd ed. Boca Raton, FL: CRC Press, 1991-1992.,p. 4-53]**QC REVIEWED**

Other Chemical/Physical Properties:

IN WATER SLIGHT HYDROLYSIS TO CHLOROUS AND CHLORIC ACIDS; STRONGLY OXIDIZING
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

DECOMP (GAS) TO CHLORIC ACID, CHLORINE, & OXYGEN IN HOT WATER
[Lide, D.R. (ed). CRC Handbook of Chemistry and Physics. 72nd ed. Boca Raton, FL: CRC Press, 1991-1992.,p. 4-53]**QC REVIEWED**

DISSOLVES IN ALKALIES FORMING A MIXTURE OF CHLORITE & CHLORATE
[Sax, N.I. and R.J. Lewis, Sr. (eds.). Hawley's Condensed Chemical Dictionary. 11th ed. New York: Van Nostrand Reinhold Co., 1987. 260]**QC REVIEWED**

Sp Gr: 3.09 g/l at 11 deg C
[Clayton, G. D. and F. E. Clayton (eds.). Patty's Industrial Hygiene and Toxicology: Volume 2A, 2B, 2C: Toxicology. 3rd ed. New York: John Wiley Sons, 1981-1982. 2955]**QC REVIEWED**

Chemical Safety & Handling:

DOT Emergency Guidelines:

Fire or explosion: May explode from friction, heat or contamination. These substances will accelerate burning when involved in a fire. May ignite combustibles (wood, paper, oil, clothing, etc.). Some will react explosively with hydrocarbons (fuels). Containers may explode when heated. Runoff may create fire or explosion hazard. /Chlorine dioxide, hydrate, frozen/
[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-143]**QC REVIEWED**

Health: TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns, or death. Fire may produce irritating and/or toxic gases. Toxic fumes or dust may accumulate in confined areas (basement, tanks, hopper/tank cars, etc.). Runoff from fire control or dilution water may cause pollution. /Chlorine dioxide, hydrate, frozen/
[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-143]**QC REVIEWED**

Public safety: CALL Emergency Response Telephone Number. ... Isolate spill or leak area immediately for at least 50 to lOO meters (160 to 330 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate closed spaces before entering. /Chlorine dioxide, hydrate, frozen/
[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-143]**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. /Chlorine dioxide, hydrate, frozen/
[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-143]**QC REVIEWED**

Evacuation: ... 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. /Chlorine dioxide, hydrate, frozen/
[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-143]**QC REVIEWED**

Fire: Small fires: Use water. Do not use dry chemicals or foams. CO2 or Halon may provide limited control. Large fires: Flood fire area with water from a distance. Do not move cargo or vehicle if cargo has been exposed to heat. Move containers from fire area if you can do it without risk. Do not get water inside containers: a violent reaction may occur. Cool containers with flooding quantities of water until well after fire is out. Dike fire-control water for later disposal. 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. /Chlorine dioxide, hydrate, frozen/
[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-143]**QC REVIEWED**

Spill or leak: Keep combustibles (wood, paper, oil, etc.) away from spilled material. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Use water spray to reduce vapors or divert vapor cloud drift. Prevent entry into waterways, sewers, basements or confined areas. Small spills: Flush area with flooding quantities of water. Large spills: DO NOT CLEAN-UP OR DISPOSE OF, EXCEPT UNDER SUPERVISION OF A SPECIALIST. /Chlorine dioxide, hydrate, frozen/
[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-143]**QC REVIEWED**

First aid: Move victim to fresh air. Call 911 or emergency medical service. Apply artificial respiration if victim is not breathing. 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. Keep victim warm and quiet. Ensure that medical personnel are aware of the material(s) involved, and take precautions to protect themselves. /Chlorine dioxide, hydrate, frozen/
[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-143]**QC REVIEWED**

Table of Water-Reactive Materials Which Produce Toxic Gases; Materials Which Produce Large Amounts of Toxic-by-Inhalation (TIH) Gas(es) When Spilled in Water. Name of Material: Chlorine dioxide, hydrate, frozen; TIH Gas Produced: Chlorine. /Chlorine dioxide, hydrate, frozen/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. TABLE]**QC REVIEWED**

Initial Isolation and Protective Action Distances (when spilled in water): Small Spills (from a small package or small leak from a large package): First, ISOLATE in all Directions 30 meters (100 feet); then, PROTECT persons Downwind during DAY 0.2 kilometers (0.1 miles) and NIGHT 0.2 kilometers (0.1 miles). LARGE SPILLS (from a large package or from many small packages): First, ISOLATE in all Directions 30 meters (100 feet); then, PROTECT persons Downwind during DAY 0.2 kilometers (0.1 miles) and NIGHT 0.6 kilometers (0.4 miles). /Chlorine dioxide, hydrate, frozen/
[U.S. Department of Transportation. 2000 Emergency Response Guidebook. RSPA P 5800.8 Edition. Washington, D.C: U.S. Government Printing Office, 2000,p. TABLE]**QC REVIEWED**

Skin, Eye and Respiratory Irritations:

MAY BE HIGHLY IRRITATING TO SKIN AND MUCOUS MEMBRANES OF RESPIRATORY TRACT. ...
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

... Irritation of the eyes ... respiratory irritation.
[Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986. 206]**QC REVIEWED**

May cause irritation of the eyes, nose, & throat. ...
[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.]**QC REVIEWED**

Fire Potential:

DANGEROUS; POWERFUL OXIDIZER.
[Sax, N.I. Dangerous Properties of Industrial Materials. 6th ed. New York, NY: Van Nostrand Reinhold, 1984. 674]**QC REVIEWED**

CONCN ABOVE 10% CAN IGNITE @ 130 DEG C. OXIDIZABLE ORGANIC DUSTS CAN LOWER DECOMPOSITION TEMP. TO AVOID DANGEROUSLY HIGH CONCN OF THE GAS, IT IS SWEPT BY AIR OR NITROGEN OUT OF REACTION VESSEL ... ABSORBED IN CHILLED WATER, THE FLOW OF WHICH IS ADJUSTED TO PRODUCE A 6-10 G/L SOLN.
[Sax, N.I. Dangerous Properties of Industrial Materials. 6th ed. New York, NY: Van Nostrand Reinhold, 1984. 324]**QC REVIEWED**

Fire Fighting Procedures:

If material on fire or involved in fire: Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) /Chlorine dioxide hydrate/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, D.C.: Assoc. of American Railroads, Hazardous Materials Systems (BOE), 1987.158]**QC REVIEWED**

If fire becomes uncontrollable, consider evacuation of one-third mile radius. /Chlorine dioxide hydrate/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, D.C.: Assoc. of American Railroads, Hazardous Materials Systems (BOE), 1987.158]**QC REVIEWED**

Explosive Limits & Potential:

REACTS VIOLENTLY WITH ORGANIC MATERIALS. IN CONCN IN EXCESS OF 10%, 1 ATM, EASILY DETONATED BY SUNLIGHT, HEAT, CONTACT WITH MERCURY OR CARBON MONOXIDE.
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

Explosive hazard by heating, exposing to sunlight, contacting mercury or carbon monoxide.
[ITII. Toxic and Hazardous Industrial Chemicals Safety Manual. Tokyo, Japan: The International Technical Information Institute, 1988. 115]**QC REVIEWED**

REACTS VIOLENTLY WITH PHOSPHORUS, POTASSIUM HYDROXIDE, SULFUR, CONCN @ FROM 0.1 TO 1 ATM OF GREATER THAN 10% IN AIR EXPLODES, ALSO MERCURIC FLUORIDE, ORGANIC MATTER, DIFLUOROAMINE.
[Sax, N.I. Dangerous Properties of Industrial Materials. 6th ed. New York, NY: Van Nostrand Reinhold, 1984. 674]**QC REVIEWED**

Explosive
[Clayton, G. D. and F. E. Clayton (eds.). Patty's Industrial Hygiene and Toxicology: Volume 2A, 2B, 2C: Toxicology. 3rd ed. New York: John Wiley Sons, 1981-1982. 2955]**QC REVIEWED**

/Chlorine dioxide/ is explosive above 45 deg C even in absence of light, and subject to long induction periods due to formation of intermediate dichlorine trioxide.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 3rd ed. Boston, MA: Butterworths, 1985. 947]**QC REVIEWED**

Hazardous Reactivities & Incompatibilities:

Incompatibilities: Carbon monoxide, hydrogen, mercury, non-metals, phosphorus pentachloride, potassium hydroxide.
[Sax, N.I. Dangerous Properties of Industrial Materials. 6th ed. New York, NY: Van Nostrand Reinhold, 1984. 674]**QC REVIEWED**

Reacts with water or steam to produce toxic & corrosive fumes of hydrochloric acid.
[Sax, N.I. Dangerous Properties of Industrial Materials. 6th ed. New York, NY: Van Nostrand Reinhold, 1984. 674]**QC REVIEWED**

Organic materials, heat, phosphorus, potassium, hydroxide, sulfur, mercury, carbon monoxide [Note: Unstable in light. A powerful oxidizer].
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 58]**QC REVIEWED**

Hazardous Decomposition:

WHEN HEATED TO DECOMPOSITION, IT EMITS TOXIC FUMES OF /HYDROGEN CHLORIDE/.
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 719]**QC REVIEWED**

Explosive decomposition at 100 deg C
[ITII. Toxic and Hazardous Industrial Chemicals Safety Manual. Tokyo, Japan: The International Technical Information Institute, 1988. 114]**QC REVIEWED**

Decomposition by sparking begins to become hazardous at concentrations of 7-8% in air.
[Bretherick, L. Handbook of Reactive Chemical Hazards. 3rd ed. Boston, MA: Butterworths, 1985. 947]**QC REVIEWED**

The gas and liquid are violently decomposed by organic materials. The gas will decompose at temperatures below the boiling point of water.
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, D.C.: Assoc. of American Railroads, Hazardous Materials Systems (BOE), 1987.158]**QC REVIEWED**

Immediately Dangerous to Life or Health:

5 ppm
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 58]**QC REVIEWED**

Protective Equipment & Clothing:

Recommendations for respirator selection. Max concn for use: 1 ppm: Respirator Class: Any chemical cartridge respirator with cartridge(s) providing protection against the compound of concern. Only nonoxidizable sorbents allowed (not charcoal). 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. 59]**QC REVIEWED**

Recommendations for respirator selection. Max concn for use: 2.5 ppm: Respirator Classes: Any supplied-air respirator operated in a continuous flow mode. Eye protection needed. Any powered, air-purifying respirator with cartridge(s) providing protection against the compound of concern. Eye protection needed. Only nonoxidizable sorbents allowed (not charcoal).
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 59]**QC REVIEWED**

Recommendations for respirator selection. Max concn for use: 5 ppm: Respirator Classes: Any chemical cartridge respirator with a full facepiece and cartridge(s) providing protection against the compound of concern. Only nonoxidizable sorbents allowed (not charcoal). Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern. Only nonoxidizable sorbents allowed (not charcoal). 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. 59]**QC REVIEWED**

Recommendations for respirator selection. Condition: Emergency or planned entry into unknown concn or IDLH conditions: Respirator Classes: 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 with a full facepiece and 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. 59]**QC REVIEWED**

Recommendations for respirator selection. Respirator Classes: Escape from suddenly occuring respiratory hazards: Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern. Only nonoxidizable sorbents allowed (not charcoal). 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. 59]**QC REVIEWED**

Wear safety glasses, rubber gloves, self-contained breathing apparatus, working clothes.
[ITII. Toxic and Hazardous Industrial Chemicals Safety Manual. Tokyo, Japan: The International Technical Information Institute, 1988. 115]**QC REVIEWED**

Wear appropriate personal protective clothing to prevent skin contact. /Liquid/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 59]**QC REVIEWED**

Wear appropriate eye protection to prevent eye contact. /Liquid/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 59]**QC 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. /Liquid/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 59]**QC 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.] /Liquid/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 59]**QC REVIEWED**

Preventive Measures:

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants.
[Sax, N.I. Dangerous Properties of Industrial Materials. 6th ed. New York, NY: Van Nostrand Reinhold, 1984. 674]**PEER REVIEWED**

OXIDIZABLE DUST SHOULD BE ELIMINATED BY FILTRATION.
[Sax, N.I. Dangerous Properties of Industrial Materials. 6th ed. New York, NY: Van Nostrand Reinhold, 1984. 674]**QC REVIEWED**

Contact lenses should not be worn when working with this chemical. /Liquid/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 59]**QC 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**

Persons not wearing protective equipment and clothing should be restricted from areas of spills or leaks until cleanup has been completed.
[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.]**QC REVIEWED**

If material not on fire and not involved in fire: Keep material out of water sources and sewers. /Chlorine dioxide hydrate/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, D.C.: Assoc. of American Railroads, Hazardous Materials Systems (BOE), 1987.158]**QC REVIEWED**

Personnel protection: Avoid breathing vapors. 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. If contact with the material anticipated, wear appropriate chemical protective clothing. /Chlorine dioxide hydrate/
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, D.C.: Assoc. of American Railroads, Hazardous Materials Systems (BOE), 1987.158]**QC REVIEWED**

The worker should immediately wash the skin when it becomes contaminated. /Liquid/
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 59]**QC 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. 59]**QC REVIEWED**

Stability/Shelf Life:

UNSTABLE IN LIGHT; STABLE IN DARK IF PURE, BUT CHLORIDES CATALYZE ITS DECOMPOSITION EVEN IN DARK.
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

SOLUTIONS IN PURE WATER CAN BE MAINTAINED FOR MONTHS IN CLOSED CONTAINERS.
[National Research Council. Drinking Water and Health. Volume 3. Washington, DC: National Academy Press, 1980. 193]**QC REVIEWED**

Storage Conditions:

MATERIALS WHICH ARE TOXIC AS STORED OR WHICH CAN DECOMPOSE INTO TOXIC COMPONENTS ... SHOULD BE STORED IN A COOL, WELL VENTILATED PLACE, OUT OF THE DIRECT RAYS OF THE SUN, AWAY FROM AREAS OF HIGH FIRE HAZARD, AND SHOULD BE PERIODICALLY INSPECTED. INCOMPATIBLE MATERIALS SHOULD BE ISOLATED... .
[Sax, N.I. Dangerous Properties of Industrial Materials. 4th ed. New York: Van Nostrand Reinhold, 1975. 539]**QC REVIEWED**

Because of explosion hazard, do not keep in storage except in diluted solution. A higher concentration of more than 10% should not be handled. Store only in dry, cool, dark place with good temperature control.
[ITII. Toxic and Hazardous Industrial Chemicals Safety Manual. Tokyo, Japan: The International Technical Information Institute, 1988. 115]**QC 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 a cylinder and leak cannot be stopped in place, remove leaking cylinder to safe place in open air, and repair leak or allow cylinder to empty. 4) If in liquid form, evacuate persons not wearing protective equipment. ... Allow ... to evaporate while providing all available ventilation.
[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.]**QC REVIEWED**

Occupational Exposure Standards:

OSHA Standards:

Permissible Exposure Limit: Table Z-1 8-hr Time Weighted Avg: 0.1 ppm (0.3 mg/cu m).
[29 CFR 1910.1000 (7/1/98)]**QC REVIEWED**

Vacated 1989 OSHA PEL TWA 0.1 ppm (0.3 mg/cu m); STEL 0.3 ppm (0.9 mg/cu m) 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. 361]**QC REVIEWED**

Threshold Limit Values:

8 hr Time Weighted Avg (TWA): 0.1 ppm; 15 min Short Term Exposure Limit (STEL): 0.3 ppm.
[American Conference of Governmental Industrial Hygienists. TLVs & BEIs: Threshold limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices for 2002. Cincinnati, OH. 2002.21]**QC REVIEWED**

NIOSH Recommendations:

Recommended Exposure Limit: 10 Hr Time Weighted Avg: 0.1 ppm (0.3 mg/cu m).
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 58]**QC REVIEWED**

Recommended Exposure Limit: 15 Min Short Term Exposure Limit: 0.3 ppm (0.9 mg/cu m).
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 58]**QC REVIEWED**

Immediately Dangerous to Life or Health:

5 ppm
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 58]**QC REVIEWED**

Other Occupational Permissible Levels:

USSR (1973): 0.03 ppm; Sweden and Germany: 0.1 ppm.
[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, 1986.118]**QC REVIEWED**

Manufacturing/Use Information:

Major Uses:

BLEACHING CELLULOSE, FLOUR, LEATHER, OILS, TEXTILES, BEESWAX; PURIFICATION OF WATER; TASTE & ODOR CONTROL OF WATER; CLEANING AND DETANNING LEATHER; MFR OF CHLORINE SALTS; OXIDIZING AGENT; BACTERICIDE & ANTISEPTIC
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

AGING ACCELERATOR IN THE MANUFACTURE OF FLOUR
[Clarke, E.G., and M. L. Clarke. Veterinary Toxicology. Baltimore, Maryland: The Williams and Wilkins Company, 1975. 257]**QC REVIEWED**

SWIMMING POOL WATER PURIFICATION
[Sax, N.I. and R.J. Lewis, Sr. (eds.). Hawley's Condensed Chemical Dictionary. 11th ed. New York: Van Nostrand Reinhold Co., 1987. 260]**QC REVIEWED**

BLEACHING AGENT FOR WOOD PULP, TALLOW
[SRI]**QC REVIEWED**

WASTEWATER DISINFECTING AGENT
[AIETA EM ET AL; US ENVIRON PROT AGENCY OFF RES DEV (REP) EPA; ISS EPA-600/9-79-018, PROG WASTEWATER DISINFECT TECHNOL 72 (1979)]**QC REVIEWED**

Manufacturers:

C Brewer & Co, Ltd, Hq, 311 Pacific St, Honolulu, Oahu, HI 96817, (808) 533-4411
[SRI. 1989 Directory of Chemical Producers -United States of America. Menlo Park, CA: SRI International, 1989.. 525]**QC REVIEWED**

International Dioxcide, Inc, Hq, 136 Central Ave, Clark, NJ 07066, (201) 499-9660; Production site: 554 Ten Rod Rd, North Kingstown, RI 02852
[SRI. 1989 Directory of Chemical Producers -United States of America. Menlo Park, CA: SRI International, 1989.. 525]**QC REVIEWED**

Scott Paper Co, Hq, Scott Plaza, Philadelphia, PA 19113, (215) 522-5000; Packaged Products Division; SD Warren Co, Division, 225 Franklin St, Boston, MA 02101; Production sites: Muskegon, MI 49443; Skowhegan, ME 04976; Westbrook, ME 04092
[SRI. 1989 Directory of Chemical Producers -United States of America. Menlo Park, CA: SRI International, 1989.. 525]**QC REVIEWED**

Methods of Manufacturing:

REACTION OF SODIUM CHLORATE AND SULFURIC ACID WITH SULFUR DIOXIDE OR REACTION OF CHLORIC ACID WITH METHANOL
[SRI]**QC REVIEWED**

... FROM CHLORINE AND SODIUM CHLORITE; POTASSIUM CHLORATE AND SULFURIC ACID; BY PASSING NITROGEN DIOXIDE THROUGH A COLUMN OF SODIUM CHLORATE.
[Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989. 324]**QC REVIEWED**

/FROM/ SODIUM CHLORATE, SULFURIC ACID AND METHANOL; SODIUM CHLORATE AND SULFUR DIOXIDE; OXIDATION OF SODIUM CHLORITE WITH CHLORINE, HYDROCHLORIC ACID, OR HYPOCHLORITE.
[International Labour Office. Encyclopedia of Occupational Health and Safety. Volumes I and II. New York: McGraw-Hill Book Co., 1971. 289]**QC REVIEWED**

General Manufacturing Information:

... TEMPERATURE AFFECTS THE RATE OF INACTIVATION OF BACTERIA WITH CHLORINE DIOXIDE. A DECREASE IN DISINFECTANT ACTIVITY WAS OBSERVED AS TEMPERATURE DECREASED FROM 30 DEG C TO 5 DEG C.
[National Research Council. Drinking Water and Health. Volume 2. Washington, DC: National Academy Press, 1980. 57]**QC REVIEWED**

IT IS NOW USED IN DRINKING WATER TREATMENT FOR CONTROL OF PHENOLS, FOR OXIDATION OF IRON & MANGANESE, & FOR FINAL DISINFECTION PRIOR TO DISTRIBUTION.
[National Research Council. Drinking Water and Health. Volume 3. Washington, DC: National Academy Press, 1980. 194]**QC REVIEWED**

CHLORINE DIOXIDE IS AN EFFECTIVE BACTERICIDE & VIRUCIDE UNDER THE PH, TEMPERATURE, & TURBIDITY THAT ARE EXPECTED IN THE TREATMENT OF POTABLE WATER.
[National Research Council. Drinking Water and Health. Volume 2. Washington, DC: National Academy Press, 1980. 61]**QC REVIEWED**

CHLORINE DIOXIDE DOES NOT FORM SIGNIFICANT AMT OF HALOGENATED ORG CMPD WHEN USED TO DISINFECT ACTIVATED-SLUDGE & MAY SUPPRESS PRODUCTION OF SUCH BY-PRODUCTS WHEN USED WITH CHLORINE.
[CHOW B, ROBERTS P; NATL CONF ENVIRON ENG (PROC) 688-94 (1979)]**QC REVIEWED**

CHLORINE DIOXIDE DISINFECTION REQUIRED LOWER DOSES & SHORTER CONTACT TIME THAN CHLORINE FOR COMPARABLE COLIFORM REDUCTIONS.
[AIETA EM ET AL; ENVIRON IMPACT HEALTH EFF 3: 697-709 (1980)]**QC REVIEWED**

CHLORINE DIOXIDE IS RAPID DISINFECTING AGENT & HAS SAME SURVIVAL RATIO AS CHLORINE BUT WITH MUCH LOWER RESIDUAL CONCN WHEN CHLORINE EXISTS AS CHLORAMINES. CHLORINE DIOXIDE IS MORE EFFECTIVE VIRUCIDE THAN CHLORINE IN SECONDARY EFFLUENT.
[AIETA EM ET AL; J AM WATER POLLUT CONTROL FED 52 (4): 810-22 (1980)]**QC REVIEWED**

A purified prepn of the simian retrovirus SA-11 containing mostly single virion particles and a prepn of cell-associated SA-11 virions were tested for their resistance to inactivation by 3 disinfectants. With chlorine dioxide both virus prepn were inactivated more rapidly at pH 10 than 6.
[Berman D, Hoff JC; Report: 17 pages (1984) ISS EPA-600/D-84-043; Order No PB84-151208]**QC REVIEWED**

The inactivation of poliovirus by chlorine dioxide is described.
[Alvarez ME, O'Brien RT; Appl Environ Microbiol 44 (5): 1064-71 (1982)]**QC REVIEWED**

SINCE CHLORITE IS FORMED AT A RATE OF 50% OF THE CHLORINE DIOXIDE DEMAND, SERIOUS CONSIDERATION MUST BE GIVEN TO LIMITING CHLORITE FORMATION BEFORE CHLORINE DIOXIDE IS ADOPTED AS DISINFECTANT TO REPLACE CHLORINE.
[MOORE GS, CALABRESE EJ; J ENVIRON PATHOL TOXICOL 4 (2-3): 513-24 (1980)]**QC REVIEWED**

Formulations/Preparations:

GRADES: SOLD AS HYDRATE, IN FROZEN FORM.
[Sax, N.I. and R.J. Lewis, Sr. (eds.). Hawley's Condensed Chemical Dictionary. 11th ed. New York: Van Nostrand Reinhold Co., 1987. 260]**QC REVIEWED**

Alcide is a germicidal prepn which has been shown to kill a wide range of common pathogenic bacteria as well as fungi, in vitro. It contains sodium chlorite and lactic acid as the active ingredients. The 2 parts are combined in equal vol immediately prior to application resulting in the formation of chlorine dioxide.
[Scatina J et al; Fundam Appl Toxicol 4 (3, Part 1): 479-84 (1984)]**QC REVIEWED**

Laboratory Methods:

Analytic Laboratory Methods:

A spectrophotometric method for the determination of residual chlorine dioxide (ClO2) in water, using the dye, Acid Chrome Violet K (CI Nr 61710; Alizarin Violet 3R), is described. The decolorization of Acid Chrome Violet K at 548 nm in an ammonia ammonium chloride (NH3-NH4Cl) buffer solution of pH 8.1 to 8.5 is specific for chlorine dioxide without interference from chlorine, chloramines, chlorite or chlorate ions in concentrations likely to be present in treated drinking water. The detection limit for chlorine dioxide using this method is 0.02 mg/l, with a standard deviation of 0.01 mg/l.
[Masschelein W et al; Ozone Sci Eng 11: 209-15 (1989)]**QC REVIEWED**

Method 9060M; The analysis of chlorine dioxide using a classical wet method for evaluating solid wastes as defined by EPA.
[USEPA/OST; List of Lists: A Catalog of Analytes and Methods p.125 (1991) OST Pub 21W-4005]**QC REVIEWED**

Method 4500-Chlorine Dioxide B. Iodometric Method for the determination of chlorine dioxide in treated surface waters. A pure solution of chlorine dioxide is prepared by slowly adding dilute sulfuric acid to a sodium chlorite solution. Contaminants such as chlorine are removed by a sodium chlorite scrubber and passing the gas into distilled water in a steady stream of air. Chlorine dioxide releases free iodine from a potassium iodide solution acidified with acetic acid or sulfuric acid. The liberated iodine is titrated with a standard solution of sodium thiosulfate, with starch as the indicator. Temperature and strong light affect solution stability. Minimize chlorine dioxide losses by storing stock chlorine dioxide solution in a dark refrigerator and by preparing and titrating dilute chlorine dioxide solutions for standardization purposes at the lowest practical temperature and in subdued light. Minimum detectable concentration: One drop (0.05 ml) of 0.01 N sodium thiosulfate is equivalent to 20 ug chlorine dioxide/l (or 40 ug/l in terms of available chlorine) when a 500 ml sample is titrated.
[Franson MA, ed; Standard Methods for the Examination of Water and Wastewater, 17th ed p. 4-76 (1989)]**QC REVIEWED**

Method 4500-Chlorine Dioxide C. Amperometric Method I for the determination of chlorine dioxide in water and wastewater. By performingfour titrations with phenylarsine oxide, free chlorine, chloramines, chlorite and chlorine dioxide may be determined separately. The first titration step consists of conversion of chlorine dioxide to chlorite and chlorate throughaddition of sufficient sodium hydroxide to produce a pH of 12, followed by neutralization to a pH of 7 and titration of free chlorine. In the second titration potassium iodide is added to a sample that has been treated similarly with alkali and had the pH adjusted to 7; titration yields free chlorine and monochloramine. The third titration involves addition of potassium iodide and pH adjustment to 7, followed by titration of free chlorine, monochloramine, and one-fifth of the available chlorine dioxide. In the fourth titration, addition of sufficient sulfuric acid to lower the pH to 2 enables all available chlorine dioxide and chlorite, to liberate an equivalent amount of iodine from the added potassium iodide and thus be titrated. Minimize effects of pH, time, and temperature of reaction by standardizing all conditions. The method distinguished various chlorine compounds with good accuracy and precision.
[Franson MA, ed; Standard Methods for the Examination of Water and Wastewater, 17th ed p. 4-78 (1989)]**QC REVIEWED**

Method 4500-Chlorine Dioxide D. DPD Method for the determination of chlorine dioxide in water and wastewater. Chlorine dioxide appears in the first step to the extent of one-fifth of its total available chlorine content corresponding to the reduction of chlorine dioxide to chlorite ion. When neutralized by bicarbonate, the color thus produced corresponds to the total available chlorine content of the chlorine dioxide. Chlorite that did not result from a positive error equal to twice this chlorite concentration. In evaluating mixtures of chloro-compounds, it is necessary to convert free chlorine into chloroaminoacetic acid by adding glycine before reacting the sample with N,N-diethyl-p-phenylenediamine (DPD) reagent. Interference appears with oxidized manganese and chromate. Iron may activate chlorite. This method has the ability to distinguish between chlorine dioxide and various forms of chlorine.
[Franson MA, ed; Standard Methods for the examination of Water and Wastewater, 17th ed p.4-79 (1989)]**QC REVIEWED**

Method 4500-Chlorine Dioxide E. Amperometric Method (II) (proposed) for the determination of chlorine dioxide in water and wastewater. The equilibrium for the reduction of the chlorine species of interest by iodide is pH-dependent. Analysis for chlorine dioxide, chlorite, and chlorate requires determination of all the chlorine and one-fifth of the chlorine dioxide at pH 7; lowering sample pH to 2 and determination of the remaining four fifths of the chlorine dioxide and all of the chlorite; preparation of a second sample by purging with nitrogen to remove chlorine dioxide and by reacting with iodide at pH 7 to remove any chlorine remaining; lowering latter sample pH to 2 and determination of all chlorine present; and, in a third sample, determination of chlorine, chlorine dioxide, chlorite, and chlorate after reduction in hydrochloric acid. This procedure can be to concentrated solutions (10 to 100 mg /l) or dilute solutions (0.1 to 10 mg/l) by appropriate selection of titrant concentration and sample size. Interferences: Iodate formation at pH values above 4 results in a negative bias in titrating the first and second sample. A positive bias results from oxidation of iodide to iodine in strongly acidic solutions. The low pH of the method is favorable to manganese, copper, and nitrite interferences. The method distinguished various chlorine compounds with good accuracy and precision.
[Franson Ma, ed; Standard Methods for the Examination of Water and Wastewater, 17th ed p.4-80 (1989)]**QC REVIEWED**

Two diffusive samplers for monitoring chlorine and chlorine dioxide in workplace air were tested. One sampler (sampler-A) was made of polymethyl methacrylate (plexiglass) and contained a polytetrafluoroethylene membrane filter. The other sampler (sampler-B) was fabricated from a three piece polystyrene aerosol cassette and contained two teflon membrane filters that had been chemically welded to the cassette. Both samplers used a 10 mM potassium iodide solution buffered to pH 7 with 1 mM potassium dihydrogenphosphate plus 1 mM sodium hydrogenphosphate as the sorbent. Chlorine and chlorine dioxide reacted with the potassium iodide solution to form chloride and chlorite ions, respectively, which were quantitated by ion chromatography. The ability of the samplers to collect chlorine and chlorine dioxide was evaluated under laboratory conditions at cumulative exposures of 0 to 10 ppm plus hours and air flow rates of 0.1 to 1 m/sec. The detection limits for chlorine dioxide and chlorine obtained with sampler-A were 0.02 and 0.07 ppm, respectively. The detection limits for sampler-B were 0.016 and 0.04 ppm, respectively. A field test was conducted at a pulp bleaching factory. Parallel sampling with impingers was also performed at the site. Chlorine and chlorine dioxide concentrations sampled by sampler-A ranged from 0.14 to 0.20 and 0.13 to 0.24 ppm, respectively. The corresponding concentrations obtained with sampler-B ranged from 0.14 to 0.18 and 0.12 to 0.27 ppm. Chlorine and chlorine dioxide concentrations obtained with the impingers were 0.10 to 0.16 and 0.062 to 0.14 ppm, respectively. The poor agreement between the data obtained with the two samplers and the impingers was attributed to an increase in acidity of the absorbing solution of the impingers over time.
[Bjorkholm E et al; Appl Occupat Environ Hyg 5 (11): 767-70 (1990)]**QC REVIEWED**

Special References:

Special Reports:

CALABRESE EJ ET AL; THE HEALTH EFFECTS OF CHLORINE DIOXIDE AS A DISINFECTANT IN POTABLE WATER: A LITERATURE SURVEY; J ENVIRON HEALTH 41 (1): 26-31 (1978). A REVIEW WITH 43 REFERENCES ON THE HEALTH EFFECTS OF CHLORINE DIOXIDE AS A DISINFECTANT IN POTABLE WATER.

MASSCHELEIN WJ; CHLORINE DIOXIDE: CHEMISTRY AND ENVIRONMENTAL IMPACT OF OXYCHLORINE COMPOUNDS; BOOK 190 pp (1980). THIS BOOK PRESENTS A GENERAL ACCOUNTING OF PRESENT KNOWLEDGE OF DIRECT & INDIRECT ENVIRONMENTAL IMPACT & CHEMICAL BASIS FOR TECHNICAL USES OF OXIDES OF CHLORINE.

Anderson AC et al; A brief review of the current status of alternatives to chlorine disinfection of water; Am J Public Health 72 (11): 1290-3 (1982). This is a review of the current status of alternatives to chlorine disinfection of water.

Couri D et al; Toxicological effects of chlorine dioxide, chlorite and chlorate; Environ Health Perspect 46: 13-17 (1982). This is a review of the toxicological effects of chlorine dioxide with 25 references.

Synonyms and Identifiers:

Synonyms:

Alcide
**QC REVIEWED**

ANTHIUM DIOXCIDE
**QC REVIEWED**

CHLORINE(IV) OXIDE
**QC REVIEWED**

CHLORINE OXIDE
**QC REVIEWED**

CHLORINE PEROXIDE
**QC REVIEWED**

CHLOROPEROXYL
**QC REVIEWED**

CHLORYL RADICAL
**QC REVIEWED**

DOXCIDE 50
**QC REVIEWED**

Formulations/Preparations:

GRADES: SOLD AS HYDRATE, IN FROZEN FORM.
[Sax, N.I. and R.J. Lewis, Sr. (eds.). Hawley's Condensed Chemical Dictionary. 11th ed. New York: Van Nostrand Reinhold Co., 1987. 260]**QC REVIEWED**

Alcide is a germicidal prepn which has been shown to kill a wide range of common pathogenic bacteria as well as fungi, in vitro. It contains sodium chlorite and lactic acid as the active ingredients. The 2 parts are combined in equal vol immediately prior to application resulting in the formation of chlorine dioxide.
[Scatina J et al; Fundam Appl Toxicol 4 (3, Part 1): 479-84 (1984)]**QC REVIEWED**

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

NA 9191; Chlorine dioxide hydrate, frozen

Standard Transportation Number:

49 181 10; Chlorine dioxide hydrate, frozen

 

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