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HYDROCHLORIC ACID
See Occupational Exposure Standards Human Health Effects:
Evidence for Carcinogenicity:
Evaluation: There is inadequate evidence for the carcinogenicity in humans of hydrochloric acid. There is inadequate evidence for the carcinogenicity in experimental animals of hydrochloric acid. Overall evaluation: Hydrochloric acid is not classifiable as to its carcinogenicity to humans (Group 3).
Human Toxicity Excerpts:
BURNS ON THE FACE MAY PRODUCE SERIOUS AND DISFIGURING SCARS. DIGESTIVE DISEASES ARE FREQUENT AND ARE CHARACTERIZED BY DENTAL MOLECULAR NECROSIS IN WHICH THE TEETH LOSE THEIR SHINE, TURN YELLOW, BECOME SOFT, POINTED, AND THEN BREAK OFF.
MISTS OF HEATED METAL PICKLING SOLN MAY CAUSE BLEEDING OF NOSE & GUMS, AS WELL AS ULCERATION OF NASAL AND ORAL MUCOSA. ...
AFTER INGESTION OF MURIATIC ACID (27% HCL), FINDINGS IN 24 PATIENTS CONSISTED OF MUCOSAL EDEMA, SUBMUCOSAL EDEMA OR HEMORRHAGE, ULCERATIONS, SLOUGHING OF MUCOSA, ATONY, & DILATATION. STRICTURES OF ESOPHAGUS WERE PRESENT IN CHRONIC PHASE.
The purpose of this study was to determine whether or not gastroduodenal acidification with either 400 ml of pH 1 citric acid or pH 0.85 hydrochloric acid resulted in ulcer type pain in patients with endoscopically documented active symptomatic duodenal ulcer under double blind randomized conditions. Gastric acidification equivalent to 80 mmol/hr failed to induce pain in most patients with active symptomatic duodenal ulcer. These observations suggest that duodenal ulcer pain is largely unrelated to duodenal acidification.
SYMPTOMATOLOGY (after ingestion or skin contact): 1) Corrosion of mucous membranes of mouth, throat, and esophagus, with immediate pain and dysphagia. The necrotic areas are at first grayish white but soon acquire a blackish discoloration and sometimes a shrunken or wrinkled texture; the process is described as a "coagulation necrosis." 2) Epigastric pain, which may be associated with nausea and the vomiting of mucoid and "coffee-ground" material. At times, gastric hemorrhage may be intense, and the vomitus then contains fresh blood. Profound thirst /SRP: may be present/. 3) Ulceration of all membranes and tissues with which the acid comes in contact ... . /Acids/
SYMPTOMATOLOGY (after ingestion or skin contact): 4) Circulatory collapse with clammy skin, weak and rapid pulse, shallow respirations, and scanty urine. Circulatory shock is often the immediate cause of death. 5) Asphyxial death due to glottic edema. 6) Late esophageal, gastric and pyloric strictures and stenoses, which may require major surgical repair, should be anticipated. Signs of obstruction commonly appear within a few weeks but may be delayed for months and even years. Permanent scars may also appear in the cornea, skin and oropharynx. 7) Uncorrected circulatory collapse of several hours' duration may lead to renal failure and ischemic lesions in the liver and heart. /Acids/
A case is reported of a hospital pharmacist's arithmetic error that resulted in a fatal dose of hydrochloric acid 20 times stronger than the strength ordered. To correct a fluid imbalance, hydrochloric acid 100 mmol/l/24 hr had been ordered.
A plant based case control study was undertaken to investigate a possible excess of brain tumor mortality identified at a Texas chemical plant from a sample based cohort study. No statistically significant associations were found.
CONCN OF 50 TO 100 PPM ARE TOLERABLE FOR 1 HR. CONCN OF 1,000 TO 2,000 PPM ARE DANGEROUS, EVEN FOR BRIEF EXPOSURES. MORE SEVERE EXPOSURES RESULT IN PULMONARY EDEMA, AND OFTEN LARYNGEAL SPASM. MISTS OF HYDROCHLORIC ACID ARE CONSIDERED LESS HARMFUL THAN ANHYD HCL, SINCE DROPLETS HAVE NO DEHYDRATING ACTION.
Hydrogen chloride (HCl) in the lung can cause /SRP: delayed/ pulmonary edema. In order for hydrogen chloride in air to reach the lung, it must be transported either as an aerosol or as a deposit on soot particles of less than 3 um in diameter. Particulates in smoke from incineration of chlorinated polymers can transport HCl gas to the lung.
Ingestion of hydrochloric acid causes edema of the glottis.
The toxicity of hydrochloric acid after inhalation or ingestion is due to local effect on the mucous membranes at the site of absorption.
... A REPORT BY SOVIET INVESTIGATORS THAT WORKERS EXPOSED TO HYDROCHLORIC ACID SUFFERED FROM GASTRITIS. A NUMBER OF CASES OF CHRONIC BRONCHITIS WERE ALSO OBSERVED.
CONTACT WITH CONCENTRATED SOLUTIONS OF HYDROCHLORIC ACID IN CLEANING METAL GIVES RISE TO SMALL BURNS AND ULCERATIONS OF THE HANDS.
Upper limit of safety for man ... about 45 mg/cu m (30 ppm) ... even this might be harmful if daily exposures were continued over periods longer than 1 month.
Although corrosive action is a drastic form of toxicity, many of the compounds that produce it are easily detoxified or excreted if presented in low concn and some, such as hydrochloric acid and iodine, are essential to the normal function of the body.
Caution: Corrosive burns may result from the inhalation of acid fumes and from skin contact with or the ingestion of strong acid. Symptoms after ingestion or skin contact include immediate pain and ulceration of all membranes and tissues which come in contact with the acid. Ingestion may be assoc with nausea, vomiting and intense thirst; corrosion of the stomach may lead within a few hours or a few days to gastric perforation and peritonitis. Late esophageal, gastric and pyloric strictures and stenoses should be anticipated. Contact of conc acid with the eye can cause extensive necrosis of the conjunctiva and corneal epithelium, resulting in perforation or opaque scarring. Chemical pneumonitis can be expected after respiratory exposure to acid vapors or after tracheobronchial aspiration of ingested acid. Death may occur due to complications such as circulatory shock, asphyxia due to glottic or laryngeal edema, perforation of the stomach with peritonitis, gastric hemorrhage, infection or anition due to stricture formation.
Sharp, pungent irritating odor; recognition odor in air 10 ppm; TLV = 5 ppm; 35 ppm causes irritation of throat; 50-100 ppm can be tolerated for 1 hr. Longer exposure may result in pulmonary edema and laryngeal spasm. Concn of 1,000-2,000 ppm are dangerous even for brief exposure. Anhydrous fumes are more harmful than mists. Can damage vision. Symptoms include vomiting, diarrhea, intense thirst, and circulatory collapse.
Inhalation of hydrochloric acid at irritating concentrations causes coughing, pain, inflammation, and edema of the upper respiratory tract. At high concn, the gas causes necrosis of the bronchial epithelium, constriction of the larynx and bronchi, and closure of the glottis. Concentrations of the 1000 to 2000 ppm and higher are immediately dangerous. One fatal case of overexposure has been reported; postmortem examination showed severe pulmonary hemorrhage, edema, and pneumonitis.
Short term exposures have been reported to induce transitory obstruction in the respiratory tract, which diminishes with repeated exposure, suggesting adaption. Acclimatized workers can work undisturbed with a hydrogen chloride level of 15 mg/cu m (10 ppm), but long-term exposure can affect the teeth, resulting in erosion of the inciso-labial surfaces.
The major effects of hydrogen chloride are those of local irritation . It is generally believed that exposure to hydrogen chloride does not result in effects on organs some distance from the portal of entry.
Small quantities are reportedly more easily detected by taste than by smell ... 52 mg/cu m (approx 35 ppm), a level below the threshold for taste or eye irritation, can induce sneezing, laryngitis, chest pain, hoarseness, and a feeling of suffocation.
In addition to determining odor threshold levels ... tests /were conducted/ to evaluate the effects of hydrochloric acid aerosols on optical chronaxie, blood vessel tone, dark adaptation, and respiration. The results varied. Inhalation of the aerosol in concentrations of 0.6-1.5 mg/cu m (0.40-1.01 ppm) shifted the value for optical chronaxie, but those of 0.2-0.4 mg/cu m (0.13-0.27 ppm) did not induce any appreciable effect. The threshold level for this test was determined statistically to be 0.6 mg/cu m (0.40 ppm), a value higher than the odor threshold reported by this author. Changes in blood vessel tone were also observed at levels above the values related to odor threshold. Only at, or above 0.5 mg/cu m (0.34 ppm) did inhalation of hydrochloric acid aerosols effect changes in vascular reactions. In contrast, the threshold levels for dark adaptation and respiration effects were similar to that for odor perception, i.e., 0.2 mg/cu m (0.13 ppm) and 0.1-0.2 mg/cu m (0.07-0.13 ppm), respectively.
Exposure to hydrochloric acid can produce burns on the skin and mucous membranes, the severity of which is related to the concentration of the solution. Subsequently, ulceration may occur, followed by keloid and retractile scarring. Contact with the eyes may produce reduced vision or blindness. frequent contact with aqueous solutions of hydrochloric acid may lead to dermatitis. ... Dental decay, with changes in tooth structure, yellowing, softening and breaking of teeth, and related digestive diseases are frequent after exposures to hydrochloric acid.
In one of eight asthmatic volunteers exposed to an aerosol of unbuffered hydrochloric acid at pH 2 for 3 min during tidal breathing, airway resistance was increased by 50%. bronchoconstriction was increased in all eight subjects after inhalation of a mixture of hydrochloric acid and glycine at pH 2.
Dysphagia and transient ulceration of the oesophagus with luminal narrowing are usually observed following ingestion of hydrochloric acid.
Ingestion by healthy volunteers of hydrochloric acid at 50 mM/day for four days resulted in a fall in blood and urinary urea, with a concomitant rise in urinary excretion of ammonia.
Acid aspiration leads to an inflammatory response characterized by the activation and pulmonary entrapment of platelets and white blood cells.
Splash contact of concentrated strong acids, such as hydrochloric acid can prove as severely and devastatingly injurious to the eye as splashes of strong alkalies.
Dental erosion of the incisors was observed in 90% of picklers in a zinc galvanizing plant in the Netherlands, who spent 27% of their time in air containing concentrations of hydrogen chloride above the exposure limit (7 mg/cu m).
Skin, Eye and Respiratory Irritations:
... HYDROGEN CHLORIDE WAS IMMEDIATELY IRRITATING WHEN INHALED AT CONCN OF 5 PPM OR MORE.
A corrosive irritant to the skin, eyes, and mucous membranes. ... A concn of 35 ppm causes irritation of the throat after short exposure.
Caution: Corrosive burns may result from the inhalation of acid fumes and from skin contact with or the ingestion of strong acid. Symptoms after ingestion or skin contact include immediate pain and ulceration of all membranes and tissues which come in contact with the acid. Ingestion may be assoc with nausea, vomiting and intense thirst; corrosion of the stomach may lead within a few hours or a few days to gastric perforation and peritonitis. Late esophageal, gastric and pyloric strictures and stenoses should be anticipated. Contact of conc acid with the eye can cause extensive necrosis of the conjunctiva and corneal epithelium, resulting in perforation or opaque scarring. Chemical pneumonitis can be expected after respiratory exposure to acid vapors or after tracheobronchial aspiration of ingested acid. Death may occur due to complications such as circulatory shock, asphyxia due to glottic or laryngeal edema, perforation of the stomach with peritonitis, gastric hemorrhage, infection or anition due to stricture formation.
Drug Warnings:
Warning: ... Correcting metabolic alkalosis ... soln of hydrochloric acid ... proved toxic and caused side effects (in cats).
Medical Surveillance:
The following medical procedures should be made available to each employee who is exposed to hydrogen chloride at potentially hazardous levels: 1. Initial medical examination: A complete history and physical examination: the purpose is to detect existing conditions that might place the exposed employee at increased risk, and to establish a baseline for future health monitoring. Examination of the respiratory system, skin, and eyes should be stressed. 14" x 17" chest roentgenogram: Hydrogen chloride causes lung damage. Surveillance of the lungs is indicated. FVC and FEV (1 sec): Hydrogen chloride is a respiratory irritant. Persons with impaired pulmonary function may be at increased risk from exposure. Periodic surveillance is indicated. 2. Periodic Medical Examination: The aforementioned medical examinations should be repeated on an annual basis, except that an X-ray is necessary only when indicated by the results of pulmonary function testing or by signs and symptoms of respiratory disease.
Populations at Special Risk:
PERSONS SUFFERING FROM SKIN, RESPIRATORY, OR DIGESTIVE DISEASES SHOULD /SRP: BE PROTECTED AGAINST WORK RELATED EXPOSURE TO HYDROCHLORIC ACID/.
Probable Routes of Human Exposure:
Process sampling, maintenance, and breakdowns /during hydrocarbon chlorination and dehydrochlorination/ may result in limited short term exposure.
Emergency Medical Treatment:
Emergency Medical Treatment:
[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:
Call for medical aid. ... Move to fresh air. If breathing has stopped, give artificial respiration. If breathing is difficult, give oxygen. ... Remove contaminated clothing and shoes. Flush affected areas with plenty of water. If swallowed and victim is conscious, have victim drink water or milk. Do not induce vomiting.
Inhalation: remove person to fresh air; keep him warm and quiet and get medical attention immediately; start artificial respiration if breathing stops. Ingestion: have person drink water or milk; do NOT induce vomiting. Eyes: immediately flush with plenty of water for at least 15 min and get medical attention; continue flushing for another 15 min if physician does not arrive promptly. Skin: immediately flush skin while removing contaminated clothing; get medical attention promptly; use soap and wash area for at least 15 min.
For immediate first aid: Ensure that adequate decontamination has been carried out. If victim is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep victim quiet and maintain normal body temperature. Obtain medical attention. /Inorganic acids and related compounds/
For 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. Monitor for pulmonary edema and treat if necessary ... Monitor for shock 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. Activated charcoal is not effective. 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. ... Do not attempt to neutralize because of exothermic reaction. Cover skin burns with dry, sterile dressings after decontamination ... . /Inorganic acids and related compounds/
Animal Toxicity Studies:
Evidence for Carcinogenicity:
Evaluation: There is inadequate evidence for the carcinogenicity in humans of hydrochloric acid. There is inadequate evidence for the carcinogenicity in experimental animals of hydrochloric acid. Overall evaluation: Hydrochloric acid is not classifiable as to its carcinogenicity to humans (Group 3).
Non-Human Toxicity Excerpts:
THE INHALATION OF AIR CONTAINING 6,400 MG/CU M FOR 30 MIN BY RABBITS AND GUINEA PIGS RESULTED IN DEATH, IN MANY INSTANCES FROM LARYNGEAL SPASM, LARYNGEAL EDEMA OR RAPIDLY DEVELOPING PULMONARY EDEMA. ... WHEN THE DURATION OF EXPOSURE WAS 2 TO 6 HR THE CONCN OF 1,000 MG/CU M CAUSED SOME FATALITIES.
... EXPOSURES OF 6 HOURS DAILY @ 100 PPM REPEATED FOR 50 DAYS CAUSED ONLY SLIGHT UNREST AND IRRITATION OF THE EYES AND NOSE OF RABBITS, GUINEA PIGS AND PIGEONS. HEMOGLOBIN CONTENT OF BLOOD ... SLIGHTLY DIMINISHED.
WHEN INHALED IN HIGH CONCN, THE GAS CAUSES NECROSIS OF THE TRACHEAL AND BRONCHIAL EPITHELIUM AS WELL AS PULMONARY EDEMA, ATELECTASIS, AND EMPHYSEMA, AND DAMAGE TO THE PULMONARY BLOOD VESSELS. /GAS/
THE REPEATED ORAL ADMINISTRATION OF DILUTE HYDROCHLORIC ACID TO DOGS INDUCES ACUTE AND CHRONIC GASTRITIS AND DUODENITIS AND LEADS TO THE APPEARANCE OF ULCERS OF THE PYLORUS, WHILE TOXIC DOSES LOWER THE ALKALINE RESERVE OF THE BLOOD.
A later study showed that severe hypoxia developed rapidly in baboons exposed to hydrogen chloride at concentrations of 3500 to 4000 ppm, a finding that confirms the earlier view that exposure to hydrogen chloride at concentrations of 1000 to 2000 ppm is dangerous even for a short time.
Baboons were exposed for 5 min to concentrations ranging from 190 to 17,290 ppm, and rats for 5 min to concentrations ranging from 11,800 to 87,660 ppm. Irritant effects were evident in all animals except baboons exposed to the lowest concentrations. ... At the highest exposure levels, animals experienced persistent respiratory effects and died after exposure.
0.1 N HYDROCHLORIC ACID (0.3 ML/KG) WAS INSTILLED INTO LEFT LOWER LOBE BRONCHUS OF ANESTHETIZED DOGS. REDUCTION IN PERFUSION TO EDEMATOUS AREA CORRELATED WITH AMT OF EXCESS LUNG LIQ, & THIS REDUCTION IN PERFUSION REDUCED TOTAL PULMONARY SHUNT.
DOSE OF 5% HYDROCHLORIC ACID CAUSED NEGLIGIBLE IRRITATION TO THE ALBINO RABBIT EYE. NEGLIGIBLE= CLEARING WITHIN 24 HR.
Hydrochloric acid has a powerful corrosive action on the living tissues of livestock. ...
Gaseous hydrogen chloride in the presence of a minute amount of vapor, rapidly inactivates bacterial spores of Bacillus subtilis; causing the spores to collapse. /Gas/
At ambient temperature, and pressure of 4 kPa, naked spores of Bacillus subtilis were reduced in viability by a factor of 100,000 within 10 sec.
Hydrochloric acid (HCl) in air can also be a phytotoxicant. Tomatoes, sugar beets, and /certain/ fruit trees are sensitive to HCl in air.
Water that contains hydrogen chloride/hydrochloric acid in a dilution of 1:175,000 or about 6 mg/l inhibits growth of the radical (stem) in plants.
The carcinogenic response to the combined and separate exposures to formaldehyde (HCHO) and hydrochloric acid (HCl) was investigated in male inbred Sprague-Dawley rats. The rats were exposed to gaseous formaldehyde 14 ppm, and HCl, 10 ppm. No carcinogenic response was observed with HCl alone.
The concn of hydrochloric acid that was found to be injurious to crops (irrigable) is 350 mg/l.
A group of 100 male Sprague Dawley rats were exposed to 10 ppm hydrochloric acid for 6 hr/day, 5 days/wk, for life (maximum 128 wk). No significant increase in mortality or tumor response among exposed animals compared with either colony control or air exposed control groups. Exposed group of animals did exhibit an increased incidence of hyperplasia of the larynx and trachea (22/99 and 26/99, respectively).
No immediate deaths occurred among rabbit and guinea pigs exposed for 5 min to a concn of 5500 mg/cu m (3685 ppm), but 100% mortality was noted in the same animal species exposed to a concn of 1000 mg/cu m (670 ppm) for 6 hr.
... Exposures insufficient to cause immediate death were associated with delayed mortality, secondary to nasal and pulmonary infections. Presumably, disruption of normal protective mechanisms allowed bacteria to invade the damaged tissues. In support of this, focal superficial ulceration of the respiratory epithelium at its junction with the squamous epithelium of the external nares was reported in mice, 24 hr after a single 10-min exposure to 25-30 mg/cu m (17 ppm).
Respiratory irritation in mice exposed to hydrogen chloride gas was studied ... Mice were exposed for 10 min to concentrations ranging from 59.6 to 1405 mg/cu m (40 to 943 ppm), and dose-response curves were plotted, using the percentage decrease in respiratory rate for each exposure as the reaction reflecting sensory irritation of the upper respiratory tract. The results showed chlorine gas to be 33 times more irritating than hydrogen chloride gas, based on RD50 values of 27 mg/cu m (9.3 ppm) for chlorine and 460 mg/cu m (309 ppm) for hydrogen chloride. The authors applied a 10-100 fold safety margin on the results of this study and projected that an appropriate threshold limit value range for human exposure to hydrogen chloride gas would be from 4.5 to 46.2 mg/cu m (3 to 31 ppm). However, the authors pointed out that other factors, besides sensory irritation, must also be considered when selecting exposure limits for man. /Gas/
... A study /was conducted/ to assess the role of hydrogen chloride gas in explaining the overall toxicity of the thermal decomposition products of polyvinyl chloride. Mice were exposed to hydrogen chloride concentrations ranging from approximately 29.8 to 29,800 mg/cu m (20 to 20,000 ppm) with deaths occurring above 12,367 mg/cu m (8,300 ppm). Histopathological changes noted in mice, killed 24 h after the exposure, revealed that the target organs included the upper respiratory tract and the eyes, with secondary changes and passive congestion in the lungs, intestine, liver, and kidneys. /Gas/
The histopathological effects in the upper respiratory tracts of mice that had been given a single 10-min exposure to hydrogen chloride, 24 h previously, were described ... Single exposure to the lowest concentration of hydrogen chloride gas tested, 25.3 mg/cu m (17 ppm), caused minimal superficial ulcerations only in the respiratory epithelium at its junction with the squamous epithelium of the external nares. As the exposure was increased to 195.2-417 mg/cu m (131-280 ppm) the adjacent respiratory epithelium underwent mucosal ulceration in a contiguous fashion; and, at 737.6 mg/cu m (493 ppm), the squamous epithelium of the external nares was also affected. At concentrations of hydrogen chloride gas of 2940 mg/cu m (1973 ppm) or more, portions of the squamous, respiratory, and olfactory epithelium of the upper respiratory tract were all affected, with mucosal damage, followed by damage to the underlying supportive tissues. /Gas/
Studies /were made/ of the effects of irritating chemicals on the mucociliary activity of excised rabbit trachea, and reported that there was a cessation of mucociliary activity after exposure to hydrogen chloride gas at a concentration of 89.4 mg/cu m (60 ppm) for 5 min or at 44.7 mg/cu m (30 ppm) for 10 min. /Gas/
... A dermal toxicity study ... reported a corrosive skin response in rabbits after a 4 hr application of 0.5 ml of a solution of hydrogen chloride in water at 170 g/L. A similar application using a solution of hydrogen chloride in water of 150 g/L was not corrosive to the skin, under the test conditons.
Application of 10 ul hydrochloric acid to the cornea of rabbits caused desquamation of the surface epithelial cells at concentrations of > or = 0.001 N.
Three weeks after intratracheal instillation of 0.5 ml of 0.08 N hydrochloric acid into hamsters, a significant increase in secretory-cell metaplasia was observed in the bronchi, evaluated by estimating the amount of secretory product in the airway epithelium on histological slides.
Studies in experimental animals in vivo and in vitro have been performed to elucidate the role of hydrochloric acid in the mammalian stomach in inducing peptic ulcers and esophagitis. Severe damage and increased permeability to H+ ions were observed in the oesophagus of rabbits after perfusion in vivo with solutions of hydrochloric acid (40-80 mM/l). Esophagitis was also observed in cats treated with hydrochloric acid (pH 1-1.3) for 1 hour. Isolated rat stomach and duodenum treated with 20-50 mM hydrochloric acid for 10 min showed extensive damage of the basal lamina. Oral administration of 0.35 N hydrochloric acid protected the gastric mucosa of rats against 0.6 N HCl-induced gastric lesions for 2 hours. The pretreatment significantly increased prostaglandin concentrations in the gastric fundic mucosa.
Hydrochloric acid did not induce reverse mutations in Escherichia coli but caused mutations in L5178Y mouse lymphoma cells at the tk locus.
Non-Human Toxicity Values:
LC50 Rat ihl 3124 ppm/1 hr
LC50 Mouse ihl 1108 ppm/1 hr
LD50 Mouse ip 1449 mg/kg
LD50 Rabbit oral 900 mg/kg
LC50 Rat ihl 4701 ppm/30 mos /Hydrogen chloride gas/
LC50 Mouse ihl 2644 ppm/30 mos /Hydrogen chloride gas/
Ecotoxicity Values:
LC100 Trout 10 mg/l/24 hr /Conditions of bioassay not specified/
LC50 Shrimp 100 to 330 ppm/48 hr (salt water) /Conditions of bioassay not specified/
LC50 Starfish 100 to 330 mg/l/48 hr /Conditions of bioassay not specified/
LC50 Cockle 330 to 1,000 mg/l/48 hr /Conditions of bioassay not specified/
TLm Gambusia affinis (mosquito fish) 282 ppm/96 hr (fresh water) /Conditions of bioassay not specified/
LC50 Carassius auratus (goldfish) 178 mg/l (1 to 2 hr survival time) /Conditions of bioassay not specified/
LC50 Shore crab 240 mg/l/48 hr /Conditions of bioassay not specified/
Lethal Lepomis macrochirus (bluegill sunfish) 3.6 mg/l/48 hr /Conditions of bioassay not specified/
LC50 Lepomis macrochirus (bluegill sunfish) 96 hr at pH between 3.5 and 3.0 /hydrogen ion concn/ /Conditions of bioassay not specified/
Metabolism/Pharmacokinetics:
Absorption, Distribution & Excretion:
Following intravenous infusion of 0.15 M hydrochloric acid into rats (50 ml/kg body weight/hour) and dogs (20 ml/kg body weight/hour), urinary excretion of the chloride ion was increased in both species.
Acute metabolic acidosis ... decreased proximal fluid reabsorption and increased the fractional delivery of sodium and calcium to the distal tubules, but not to the final urine. In comparison with normal dogs, dogs with chronic metabolic acidosis showed an increase in proximal fluid reabsorption and a dissociation of calcium from sodium reabsorption more distally, leading to an increase delivery of calcium relative to the sodium at the distal tubule and in the final urine.
Acids that are more lipid-soluble have greater penetration capability and produce more tissue damage. Sulfurous acid is more lipid-soluble than hydrochloric acid, followed by phosphoric acid and sulfuric acids. /Acids/
Mechanism of Action:
The biological activity of hydrogen chloride is associated with its high solubility in water i.e., 23 moles/L at 0 deg C. ... The hydrogen chloride in water dissociates almost completely, with the hydrogen ion captured by the water molecules to form the hydronium ion. The hydronium ion becomes a donor of a proton that possesses catalytic properties and thus is capable of reacting with organic molecules. This may explain the ability of hydrogen chloride to induce cellular injury and necrosis.
Interactions:
Hydrochloric acid, carbon monoxide, and unsaturated carbon cmpd interactions account for the extreme toxicity of gases from polyvinyl chloride and other chloride containing polymers.
Pharmacology:
Therapeutic Uses:
... IN TREATMENT OF GASTRIC ACHLORHYDRIA. ... FREE ACID IS ADMIN AS DILUTED HYDROCHLORIDE ACID (10%) IN DOSE OF 5 TO 10 ML IN 125 TO 250 ML OF WATER, OFTEN IN SEVERAL DIVIDED DOSES @ 15-MIN INTERVAL. IT MUST BE SIPPED THROUGH A TUBE.
VET: INTERNALLY ... IN ACHLORHYDRIA & HYPOCHLORHYDRIA ESP IN PUPS & IN SOME DOGS ... UP TO 2 YR OF AGE. ... ORALLY, IN RUMEN ATONY OF CATTLE ESP IN THOSE CASES ASSOC WITH ACETONEMIA. ... EFFECTIVE TOPICALLY ON MOLD SPORES (1-2%) & ANTIBACTERIAL AGAINST MANY ORGANISMS. ...
PHARMACEUTIC AID (ACIDIFYING AGENT); VET: HAS BEEN USED AS GASTRIC ACIDIFIER.
MEDICATION (VET): ANTISEPTIC
MEDICATION (VET): INTERNALLY.
Drug Warnings:
Warning: ... Correcting metabolic alkalosis ... soln of hydrochloric acid ... proved toxic and caused side effects (in cats).
Interactions:
Hydrochloric acid, carbon monoxide, and unsaturated carbon cmpd interactions account for the extreme toxicity of gases from polyvinyl chloride and other chloride containing polymers.
Environmental Fate & Exposure:
Probable Routes of Human Exposure:
Process sampling, maintenance, and breakdowns /during hydrocarbon chlorination and dehydrochlorination/ may result in limited short term exposure.
Natural Pollution Sources:
OCCURS IN THE GASES EVOLVED FROM MANY VOLCANOES. /GAS/
Artificial Pollution Sources:
Combustion of fuels (organic chlorides and gasoline) produces hydrogen chloride. /Gas/
Hydrochloric acid is produced from refuse incineration and the secondary metals industry (smelting of scrap, not of ore). /Gas/
From thermodecomposition of gases: From pyrolysis of some wire insulation materials such as polyvinyl chloride, also chlorinated acrylics and retardant treated materials. /Gas/
Hydrogen chloride is formed as a by-product in the numerous dehydrohalogenation processes used to make unsaturated compounds from the parent chlorinated hydrocarbon.
... Coal fired power plant/s/ ... .
Environmental Fate:
Terrestrial Fate: When anhydrous hydrogen chloride is spilled onto the soil, extensive evaporation will occur. Therefore, with regard to infiltration into the soil, only hydrochloric acid is considered. However, when hydrochloric acid is spilled onto soil, it will begin to infiltrate. The presence of water in the soil will influence the rate of chemical movement in the soil. During transport through the soil, hydrochloric acid will dissolve some of the soil material, in particular those of a carbonate base. The acid will be neutralized to some degree. However, significant amounts of acid are expected to remain for transport ... .
Hydrogen chloride in water dissociates almost completely, with the hydrogen ion captured by the water molecules to form the hydronium ion.
Environmental Abiotic Degradation:
Hydrogen chloride in water dissociates almost completely, with the hydrogen ion captured by the water molecules to form the hydronium ion.
Atmospheric Concentrations:
IT IS A COMMON AIR CONTAMINANT. /GAS/
Environmental Standards & Regulations:
FIFRA Requirements:
Residues of hydrochloric acid are exempted from the requirement of a tolerance when used as a solvent, neutralizer in accordance with good agricultural practices as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops or to raw agricultural commodities after harvest.
As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their future use. Under this pesticide reregistration program, EPA examines health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether they are eligible for reregistration. In addition, all pesticides must meet the new safety standard of the Food Quality Protection Act of 1996. Pesticides for which EPA had not issued Registration Standards prior to the effective date of FIFRA, as amended in 1988, were divided into three lists based upon their potential for human exposure and other factors, with List B containing pesticides of greater concern and List D pesticides of less concern. Hydrogen chloride is found on List D. Case No: 4064; Pesticide type: fungicide, herbicide, antimicrobial; Case Status: RED Approved 02/94; OPP has made a decision that some/all uses of the pesticide are eligible for reregistration, as reflected in a Reregistration Eligibility Decision (RED) document .; Active ingredient (AI): hydrogen chloride; AI Status: OPP has completed a Reregistration Eligibility Decision (RED) document for the case/AI.
CERCLA Reportable Quantities:
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. Hydrogen chloride is an extremely hazardous substance (EHS) subject to reporting requirements when stored in amounts in excess of its threshold planning quantity (TPQ) of 500 lbs. /Gas form only/
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).
Atmospheric Standards:
Listed as a hazardous air pollutant (HAP) generally known or suspected to cause serious health problems. The Clean Air Act, as amended in 1990, directs EPA to set standards requiring major sources to sharply reduce routine emissions of toxic pollutants. EPA is required to establish and phase in specific performance based standards for all air emission sources that emit one or more of the listed pollutants. Hydrochloric acid is included on this list.
Clean Water Act Requirements:
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.
FDA Requirements:
Hydrochloric acid used as a buffer and neutralizing agent in animal drugs, feeds, and related products is generally recognized as safe when used in accordance with good manufacturing or feeding practice.
Hydrochloric acid used as a buffer and neutralizing agent in food for human consumption is generally recognized as safe when used in accordance with good manufacturing practice.
Allowable Tolerances:
Residues of hydrochloric acid are exempted from the requirement of a tolerance when used as a solvent, neutralizer in accordance with good agricultural practices as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops or to raw agricultural commodities after harvest.
Chemical/Physical Properties:
Molecular Formula:
Cl-H
Molecular Weight:
36.46
Color/Form:
Colorless or slightly yellow fuming liquid
Pale yellow liquid
Odor:
Pungent, irritating odor
Taste:
Taste threshold: 1.60X10-4 moles/l (recognition in water, chemically pure); 1.30X10-4 M/l (recognition in water, chemically pure); 1.10X10-4 M/l (recognition in water, chemically pure)
Boiling Point:
108.58 deg C containing 20.22% HCl in water
Corrosivity:
Aq soln of hydrochloric acid attack nearly all metals (mercury, silver, gold, platinum, tantalum, and certain alloys are exceptions).
Hydrochloric acid (HCl) is one of the most corrosive of the nonoxidizing acids in contact with copper alloys, and is successfully handled in dilute solutions. The corrosion rate of cupro-nickel in 2N HCl at 24 deg C is 2.3-7.6 mm/yr, depending upon the degree of aeration and other factors.
Anhydrous hydrogen chloride is not corrosive. /Hydrochloric acid gas/
Hydrochloric acid is a strong, highly corrosive acid
Density/Specific Gravity:
1.05 @ 15 deg C/4 deg C (10.17% w/w soln); 1.10 @ 20 deg C/4 deg C (20% w/w soln); 1.15 (29.57%); 1.20 (39.11%)
Heat of Vaporization:
178 Btu/lb= 98.6 cal/g= 4.13X10+5 J/kg
pH:
pH: 0.10 (1.0 N); 1.10 (0.1 N); 2.02 (0.01 N); 3.02 (0.001 N); 4.01 (0.0001 N)
Solubilities:
56.1 G/100 CC HOT WATER @ 60 DEG C
82.3 G/100 CC COLD WATER @ 0 DEG C
327 G/100 CC ALCOHOL
SOL IN BENZENE
SOL IN ETHER; INSOL IN HYDROCARBONS
Soluble in water, alcohol, and benzene
Spectral Properties:
Index of refraction: 1.34168 @ 18 deg C/D (1.0 N soln)
Other Chemical/Physical Properties:
Ratio of Specific Heat of Vapor: 1.398 /Hydrochloric acid gas/
Decomposition temperature: 1782 deg C.
Critical density: 424 g/l /Hydrochloric acid gas/
Heat of Soln: -860 Btu/lb= -480 cal/g= -20X10+5 J/kg
Heat of fusion= 0.476 kcal/mole
MAY BE COLORED YELLOW BY TRACES OF IRON, CHLORINE, AND ORGANIC MATTER.
BP: -84.9 DEG C /GAS/
MP: -114.8 DEG C /GAS/
Freezing pt (deg C): -17.4 (10.81% soln); -62.25 (20.69% soln); -46.2 (31.24% soln); -25.4 (39.17% soln), Gemlin's, chlorine (8th ed) 6,136-137 (1927).
Boiling weaker or stronger aqueous solution results in loss of either component until constant boiling acid is obtained.
Attacks most metal with the evolution of hydrogen.
Refractive index: gas at 273.16 deg K= 1.00 /gas/
... mixing of formaldehyde and hydrogen chloride could result in generation of bis(chloromethyl)ether, a potent human carcinogen.
Colorless gas /Hydrochloric acid, gas/
Colorless to slightly yellow gas (Note: Shipped as a liquefied compressed gas).
Critical temperature: 51.54 deg C; Critical pressure: 8.316 MPa (82.34 atm) /Hydrochloric acid gas/
Refractive index: liquid at 283.16 deg K= 1.254 /Hydrochloric acid gas/
Surface tension at 118.16 deg K is 23 mN/cm /Hydrochloric acid gas/
Vapor pressure= 3.54X10+4 mm Hg @ 25 deg C /Hydrochloric acid gas/
Viscosity: Liquid at 118.16 K, 0.405 mPa.s; Vapor at 273.06 K, 0.0131 mPa.s /Hydrochloric acid gas/
Chemical Safety & Handling:
DOT Emergency Guidelines:
Health: Highly toxic, may be fatal if inhaled, swallowed or absorbed through skin. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution. /Hydrochloric acid; Hydrochloric acid, mixture; Hydrochloric acid, solution/
Fire or explosion: Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Containers may explode when heated. Runoff may pollute waterways. /Hydrochloric acid; Hydrochloric acid, mixture; Hydrochloric acid, solution/
Public safety: CALL Emergency Response Telephone Number. ... Isolate spill or leak area immediately for at least 25 to 50 meters (80 to 160 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. /Hydrochloric acid; Hydrochloric acid, mixture; Hydrochloric acid, solution/
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. /Hydrochloric acid; Hydrochloric acid, mixture; Hydrochloric acid, solution/
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. /Hydrochloric acid; Hydrochloric acid, mixture; Hydrochloric acid, solution/
Fire: Small fires: Dry chemical, CO2 or water spray. Large fires: Water spray, fog or regular 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. Do not get water inside containers. 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. /Hydrochloric acid; Hydrochloric acid, mixture; Hydrochloric acid, solution/
Spill or leak: Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Cover with plastic sheet to prevent spreading. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. /Hydrochloric acid; Hydrochloric acid, mixture; Hydrochloric acid, solution/
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. For minor skin contact, avoid spreading material on unaffected skin. 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. /Hydrochloric acid; Hydrochloric acid, mixture; Hydrochloric acid, solution/
Odor Threshold:
Air: 0.77 ul/l; Odor safety class C; C= less than 50% of distracted persons perceive warning of TLV.
Odor low: 7.0 mg/cu m; Odor high: 49.0 mg/cu m; strong irritating odor; Irritating concn= 49.00 mg/cu m.
Low threshold= 0.26 ppm. High threshold= 0.3 ppm.
Skin, Eye and Respiratory Irritations:
... HYDROGEN CHLORIDE WAS IMMEDIATELY IRRITATING WHEN INHALED AT CONCN OF 5 PPM OR MORE.
A corrosive irritant to the skin, eyes, and mucous membranes. ... A concn of 35 ppm causes irritation of the throat after short exposure.
Caution: Corrosive burns may result from the inhalation of acid fumes and from skin contact with or the ingestion of strong acid. Symptoms after ingestion or skin contact include immediate pain and ulceration of all membranes and tissues which come in contact with the acid. Ingestion may be assoc with nausea, vomiting and intense thirst; corrosion of the stomach may lead within a few hours or a few days to gastric perforation and peritonitis. Late esophageal, gastric and pyloric strictures and stenoses should be anticipated. Contact of conc acid with the eye can cause extensive necrosis of the conjunctiva and corneal epithelium, resulting in perforation or opaque scarring. Chemical pneumonitis can be expected after respiratory exposure to acid vapors or after tracheobronchial aspiration of ingested acid. Death may occur due to complications such as circulatory shock, asphyxia due to glottic or laryngeal edema, perforation of the stomach with peritonitis, gastric hemorrhage, infection or anition due to stricture formation.
Fire Fighting Procedures:
Use water spray to keep fire-exposed containers cool. Extinguish fire using agent suitable for surrounding fire. /Hydrogen chloride, anhydrous; hydrogen chloride, refrigerated liquid/
If material involved in fire: Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty). Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible.
Not flammable. Flammable gas may be produced on contact with metals. Wear chemical protective suit with self-contained breathing apparatus.
Firefighting Hazards:
Confined fires with high fuel loads of polyvinyl chloride, such as a fire in a vault with a high load of polyvinyl chloride coated electrical wiring, may generate sufficient hydrogen chloride to cause irritation in fire fighters. Rapid combustion of relatively large amt of polymer may yield ... hydrogen chloride ... .
Explosive Limits & Potential:
Behavior in fire: Pressurized container may explode and release toxic, irritating vapors.
Hazardous Reactivities & Incompatibilities:
Inadvertent mixing of formaldehyde and hydrogen chloride could result in generation of bis(chloromethyl)ether, a potent human carcinogen.
Anhydrous hydrogen chloride is rapidly absorbed in water to form corrosive hydrochloric acid. Aqueous hydrochloric acid solutions are quite reactive. Reacts vigorously with alkalies and with many organic materials. Strong oxidizing materials cause release of chlorine. /Hydrogen chloride, anhydrous; hydrogen chloride, refrigerated liquid/
CESIUM ACETYLENE CARBIDE BURNS IN HYDROGEN CHLORIDE GAS. CESIUM CARBIDE IGNITES IN CONTACT WITH HYDROCHLORIC ACID UNLESS ACID IS DILUTE. /GAS/
LITHIUM SILICIDE IN CONTACT WITH HYDROGEN CHLORIDE BECOMES INCANDESCENT. WHEN DILUTE HYDROCHLORIC ACID IS USED, GAS SPONTANEOUSLY FLAMMABLE IN AIR IS EVOLVED. MAGNESIUM BORIDE ... TREATED WITH CONCN HYDROCHLORIC ACID PRODUCES SPONTANEOUSLY FLAMMABLE GAS.
RUBIDIUM ACETYLENE CARBIDE BURNS WITH SLIGHTLY WARM HYDROCHLORIC ACID OR WITH MOLTEN SULFUR. RUBIDIUM CARBIDE IGNITES IN CONTACT WITH HYDROCHLORIC ACID UNLESS ACID IS DILUTE.
URANIUM PHOSPHIDE REACTS WITH HYDROCHLORIC ACID TO RELEASE SPONTANEOUSLY FLAMMABLE PHOSPHINE.
CALCIUM CARBIDE REACTS WITH HYDROGEN CHLORIDE GAS WITH INCANDESCENCE.
CALCIUM PHOSPHIDE & HYDROCHLORIC ACID UNDERGO VERY ENERGETIC REACTION.
ABSORPTION OF GASEOUS HYDROGEN CHLORIDE ON MERCURIC SULFATE BECOMES VIOLENT @ 125 DEG C. SODIUM REACTS VERY VIGOROUSLY WITH GASEOUS HYDROGEN CHLORIDE. /GAS/
REACTION OF SILVER PERCHLORATE WITH CARBON TETRACHLORIDE IN PRESENCE OF SMALL AMT OF HYDROCHLORIC ACID PRODUCES TRICHLOROMETHYL PERCHLORATE, WHICH DETONATES @ 40 DEG C.
Aqueous hydrochloric acid solutions react with most metals, forming flammable hydrogen gas. /Hydrogen chloride, anhydrous; hydrogen chloride, refrigerated liquid/
Hydroxides, amines, alkalis, copper, brass, zinc [Note: Hydrochloric acid is highly corrosive to most metals].
With sulfuric acid: Accidental addition of 6,500 liters of concn hydrochloric acid to a bulk sulfuric acid storage tank released sufficient hydrogen chloride by dehydration to cause the tank to explode violently. Complete dehydration of hydrochloric acid solution releases some 250 volumes of gas.
Hazardous Decomposition:
When heated to decomp it emits toxic fumes of ... /hydrogen chloride/.
Hazardous Polymerization:
Aldehydes and epoxides in the presence of hydrochloric acid cause violent polymerization. Alcohol and glycols in the presence of hydrochloric acid lead to dehydration reactions.
Prior History of Accidents:
A storage tank, containing about 750,000 l of 32% hydrochloric acid solution, started to leak its contents when the natural rubber protective lining of the tank deteriorated and the acid dissolved the flange at its base. Approximately 380,000 l of the hydrochloric solution spilled on the ground and flowed towards a nearby river before remedial actions were undertaken. A vapor cloud occurred above the spill and dissipated within 300 m of the spill site. Firefighters initially used water to wash the acid out of the spill area. This spill action was halted to reduce the amount of acid reaching the river. Response crews arrived at the spill site, wearing protective clothing and filter masks. Fourteen truckloads of oyster shells were applied onto the spill area. The shells served a dual purpose; Temporary containment of the acid by building dams with the shells and neutralization. The neutralized residue was then raked and shoveled into containers for disposal. The remaining hydrochloric acid in the leaking tank was transferred to another tank. The acid, that reached the river, killed more than 20 fish and a few blue crabs. Water samples revealed no abnormal environmental effects since the river had been highly polluted for quite some time. Several response personnel developed facial rashes two or three days after the incident. This may have resulted when the winds suddenly shifted direction and increased the exposure of acid fumes to their faces.
Immediately Dangerous to Life or Health:
50 ppm
Protective Equipment & Clothing:
WORKERS SHOULD WEAR ACID RESISTANT PROTECTIVE CLOTHING, INCL HOODS, EYE & FACE PROTECTION, ACID RESISTANT HAND & ARM PROTECTION, & FOOT & LEG PROTECTION ... WORKERS SHOULD WEAR RESP PROTECTIVE EQUIPMENT OF SELF CONTAINED OR CANISTER TYPE DEPENDING ON CONCN.
For entry into a situation where the spilled material and its characteristics are unknown ... a totally encapsulated chemical suit should be worn.
Employees should be provided with and required to use impervious clothing, gloves, face shields (eight inch minimum), splash proof goggles, and other appropriate protective clothing necessary to prevent any possiblity of skin contact with mists or solutions of hydrogen chloride which have a pH equal to or less than 3.0.
Non-impervious clothing that becomes wet with solutions of hydrogen chloride or contaminated with hydrogen chloride should be removed immediately and not reworn until the hydrogen chloride is removed from the clothing.
Vendor recommendations concerning the protective qualities of materials are as follow: neoprene, nitrile, chlorinated polyethylene, and polyvinyl alcohol received A (highest) or B (good) ratings from three or more venders, Natural rubber and nitrile/polyvinyl chloride received A (highest) or B (good) ratings from less than three vendors, B (good) and C (fair) ratings, with B's predominating, from several vendors, Neoprene/styrene-butadiene rubber and polyurethane received B (good) and C (fair) ratings, with C's predominating, from several vendors, C (fair) or D (poor) ratings from less than three vendors.
Only NIOSH-approved or OSHA-approved equipment should be used. Use of supplied- air suits may be necessary to prevent skin contact while providing respiratory protection from airborne concentrations of hydrogen chloride; however, this equipment should be selected, used, and maintained under the immediate supervision of trained personnel. Where supplied-air suits are used above a concentration of 100 ppm, an auxiliary self-contained breathing apparatus operated in positive pressure mode should also be worn.
Breakthrough times of chlorinated polyethylene are greater than one hour reported by (normally) two or more testers. There are some data suggesting breakthrough times of polycarbonate to be approximately an hour or more.
Breakthrough times of natural rubber, neoprene, nitrile, and polyvinyl chloride are greater than one hour reported by (normally) two or more testers. Breakthrough times of natural rubber and neoprene are greater than one hour reported by (normally) two or more testers. There are some data suggesting the breakthrough times of nitrile, polyvinyl chloride, Viton, and Saranex to be approximately an hour or more. /Hydrochloric acid, 30-70%/
WORKSHOPS IN WHICH HYDROCHLORIC ACID IS FREQUENTLY HANDLED SHOULD BE EQUIPPED WITH EMERGENCY SHOWERS AND EYEWASH EQUIPMENT, ETC.
Wear appropriate personal protective clothing to prevent skin contact.
Wear appropriate personal protective clothing to prevent the skin from becoming frozen from contact with the liquid or from contact with vessels containing the liquid.
Wear appropriate eye protection to prevent eye contact with the liquid that could result in burns or tissue damage from frostbite.
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.
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 should 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.]
Quick drench facilities and/or eyewash fountains should be provided within the immediate work area for emergency use where there is any possibility of exposure to liquids that are extremely cold or rapidly evaporating.
Recommendations for respirator selection. Max concn for use: 50 ppm. Respirator Class(es): Any chemical cartridge respirator with cartridge(s) providing protection against the compound of concern. May require eye protection. Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern. Any powered, air-purifying respirator with cartridge(s) providing protection against the compound of concern. May require eye protection. Any supplied-air respirator. May require eye protection. Any self-contained breathing apparatus with a full facepiece.
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 a 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.
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 acid gas canister. Any appropriate escape-type, self-contained breathing apparatus.
Avoid contact by leakage or otherwise with all common metal. PVA not recommended for gloves; eye protectors and rubberized clothing should be worn in spill area. Respiratory equipment may be necessary and should not be constructed of materials susceptible to rapid corrosion by acid.
Preventive Measures:
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.
HYDROCHLORIC ACID SHOULD BE MANUFACTURED IN CLOSED SYSTEMS; PARTICULAR ATTENTION SHOULD BE PAID TO THE DETECTION OF LEAKS ... WHEN HANDLING ... (LOADING, UNLOADING, AND DECANTING), MEASURES SHOULD BE TAKEN TO AVOID SPLASHES OR THE INHALATION OF VAPORS ... DIFFICULT OPERATIONS SHOULD BE CARRIED OUT IN FUME CUPBOARDS OR UNDER EXHAUST VENTILATION AND AN ABUNDANT SUPPLY OF WATER SHOULD ALWAYS BE AVAILABLE ... WORKERS SHOULD NEVER ENTER TANKS OR OTHER VESSELS THAT HAVE CONTAINED HYDROCHLORIC ACID UNTIL ... THEY HAVE BEEN CLEANED.
Aqueous scrubbers are used to control hydrogen chloride emissions from vent stacks and other sources.
If material not involved in fire: Keep material out of water sources, and sewers. Build dikes to contain flow as necessary. Use water spray to knock down vapors. Neutralize spilled material with crushed limestone, soda ash, or lime.
Contact lenses should not be worn when working with this chemical.
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. Contaminated clothing should not be taken home at end of shift, but should remain at employee's place of work for cleaning.
The worker should immediately wash the skin when it becomes contaminated.
Work clothing that becomes wet or significantly contaminated should be removed or replaced.
Stability/Shelf Life:
Hydrochloric acid has high thermal stability.
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)./
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.
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.
Storage Conditions:
Store in cool, dry, well-ventilated location. Separate from oxidizing materials, organic materials, and alkalies. /Hydrogen chloride, anhydrous; hydrogen chloride, refrigerated liquid/
THE ACID SHOULD NOT BE STORED IN THE VICINITY OF FLAMMABLE OR OXIDIZING SUBSTANCES, EG NITRIC ACID OR CHLORATES, OR NEAR METALS AND METAL HYDRIDES THAT MAY BE ATTACKED BY THE ACID ... ELECTRICAL EQUIPMENT SHOULD BE FLAMEPROOF AND PROTECTED AGAINST CORROSIVE ACTION. ...
No part of a cylinder should be subjected to a temp above 52 deg C.
STORAGE AREAS SHOULD BE WELL VENTILATED AND HAVE A CEMENT FLOOR AND SHELTER FROM DIRECT SUNLIGHT AND HEAT SHOULD BE PROVIDED.
Storage temp: Ambient or lower; Venting: Safety relief.
Cleanup Methods:
If hydrogen chloride gas is leaked ... 1. Ventilate area of leak to disperse gas. 2. Stop flow of gas. If source of leak is a cylinder and the leak cannot be stopped in place, remove the leaking cylinder to a safe place in the open air, and repair the leak or allow the cylinder to empty. If soln of hydrogen chloride is spilled ... 1. Collect or confine spilled material in the most convenient and safe manner. 2. If possible, reclaim the spilled material. If this is not possible; 3. Dilute and/or neutralize and dispose of in a secured sanitary landfill. /Gas/
Spills in Water: Sodium bicarbonate is recommended as an in situ neutralizing agent.
During scrubbing (an air pollution control method), water is used for removing hydrochloric acid.
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 polyurethan or foamed concrete. Absorb bulk liquid with fly ash or cement powder. Neutralize with agricultural lime (CaO), crushed limestone (CaCO3) or sodium bicarbonate (NaHCO3). Water spill: Neutralize with agricultural lime (CaO), crushed limestone (CaCO3) or sodium bicarbonate (NaHCO3). Air spill: Apply water spray or mist to knock down vapors. Vapor knockdown water is corrosive or toxic and should be diked for containment.
The following absorbent materials have been tested and recommended for vapor suppression and/or containment of 26% and 35% hydrochloric acid solutions: a mixture of (75%) anionic polyacrylamide (R1779) and (25%) nonionic polyacrylamide (Versicol W25), individually use the anionic polyacrylamide or nonionic polyacrylamide, and Cellosize WP3H (hydroxyethyl cellulose).
Environmental considerations -- water spill: Neutralize with agricultural lime (CaO), crushed limestone (CaCO3), or sodium bicarbonate (NaHCO3).
Environmental considerations -- air spill: Apply water spray or mist to knock down vapors. Vapor knockdown water is corrosive or toxic and should be diked for containment.
Approach release from upwind. Stop or control the leak, if this can be done without undue risk. Use water fog or spray to knock down and absorb vapors. Releases may require isolation or evacuation. Control runoff and isolate discharged material for proper disposal. /Hydrogen chloride, anhydrous; hydrogen chloride, refrigerated liquid/
Disposal Methods:
SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.
Neutralization: Neutralize with limestone (CaCO3), soda ash (Na2CO3) or slaked lime (Ca(OH)2). Flushing to sewer with high dilution depends on allowable neutral salt concn in effluent water. Consider use of waste acid to neutralize alkaline wastes.
Dilute through addition to ice water, quench, and neutralize with lime, or caustic solution. ... Contact local sewage authority. Occupational Exposure Standards:
OSHA Standards:
Permissible Exposure Limit: Table Z-1 Ceiling value: 5 ppm (7 mg/cu m).
Threshold Limit Values:
Ceiling Limit: 5 ppm.
Notice of Intended Change for 2002: These substances, with their corresponding values and notations, comprise those for which a limit has been proposed for the first time or for which a change in the Adopted value is proposed. In each case, the proposed values should be considered trial values for the year following ratification by the ACGIH Board of Directors. If, during the year, no evidence comes to light that questions the appropriateness of these proposals, the values will be reconsidered for adoption as TLVs. Ceiling Limit: 2 ppm. A4; Not classifiable as a human carcinogen.
NIOSH Recommendations: Recommende |