Hydrogen Chloride 

Hydrogen Chloride (HCl)
 

CAS 7647-01-0; UN 1050 (anhydrous), UN 1789 (solution),
 

UN 2186 (refrigerated liquefied gas)
 

Synonyms for an aqueous solution of hydrogen chloride include chlorohydric acid, hydrochloric acid, 

and muriatic acid. 

C Persons exposed only to hydrogen chloride gas do not pose significant risks of 

secondary contamination. Persons whose clothing or skin is contaminated with 

hydrochloric acid can cause secondary contamination by direct contact or through 

off-gassing vapor. 

C Hydrogen chloride is a colorless, corrosive, nonflammable gas that fumes in air. It has 

a characteristic pungent odor. It is heavier than air and may accumulate in low-lying 

areas. 

C Hydrogen chloride is not absorbed through the skin, but when hydrogen chloride gas 

comes in contact with moisture, it forms hydrochloric acid, which is corrosive and 

can cause irritation and burns. 

Description At room temperature, hydrogen chloride is a colorless to slightly 

yellow gas with a pungent odor. On exposure to air, the gas 

forms dense white vapors due to condensation with atmospheric 

moisture. The vapor is corrosive, and air concentrations above 

5 ppm can cause irritation. 

Hydrogen chloride is available commercially as an anhydrous gas 

or as aqueous solutions (hydrochloric acid). Commercial 

concentrated hydrochloric acid contains 36% to 38% hydrogen 

chloride in water. Aqueous solutions generally are colorless but 

may be yellow due to traces of iron, chlorine, and organic 

impurities. 

Routes of Exposure 

Inhalation Inhalation is an important route of exposure to hydrogen 

chloride. Its odor and highly irritating properties generally 

provide adequate warning for acute, high-level exposures. 

However, only 50% of exposed persons can perceive hydrogen 

chloride’s odor at the OSHA permissible exposure limit (5 ppm), 

and odor may not provide adequate warning in the 

workplace. Hydrogen chloride vapor is heavier than air and may 

cause asphyxiation in enclosed, poorly ventilated, or low-lying 

areas. 

ATSDR • General Information 1 
 

Hydrogen Chloride 

Skin/Eye Contact 

Ingestion 

Sources/Uses 

Standards and 

Guidelines 

Physical Properties 

Children exposed to the same levels of hydrogen chloride as 

adults may receive larger dose because they have greater lung 

surface area:body weight ratios and increased minute 

volumes:weight ratios. In addition, they may be exposed to 

higher levels than adults in the same location because of their 

short stature and the higher levels of hydrogen chloride found 

nearer to the ground. 

Hydrogen chloride is not absorbed through the skin. Direct 

contact with aqueous solutions of hydrogen chloride or with 

concentrated vapor can cause severe chemical burns. 

Children are more vulnerable to toxicants affecting the skin 

because of their relatively larger surface area:body weight ratio. 

Ingestion of concentrated hydrochloric acid can cause severe 

corrosive injury to the lips, mouth, throat, esophagus, and 

stomach. 

Hydrogen chloride is produced commercially by any of the 

following reactions: heated hydrogen gas with calcium chloride, 

sulfuric acid with sodium chloride, sodium chloride with sulfur 

dioxide and steam, and hydrogen burned in chlorine. Hydrogen 

chloride can be formed during the combustion of many plastics. 

Hydrochloric acid (muriatic acid) is a component of commercial 

chemicals used to clean and disinfect swimming pools. 

Hydrogen chloride is used for cleaning, pickling, and 

electroplating metals; in refining mineral ores; in petroleum well 

extraction; in leather tanning; and in the refining of fats, soaps, 

and edible oils. It is also used in producing polymers and 

plastics, rubber, fertilizers, dyes, dyestuffs, and pigments. 

OSHA PEL (permissible exposure limit) = 5 ppm (ceiling) 

NIOSH IDLH (immediately dangerous to life or health) = 

50 ppm 

AIHA ERPG-2 (emergency response planning guideline) 

(maximum airborne concentration below which it is believed that 

nearly all individuals could be exposed for up to 1 hour without 

experiencing or developing irreversible or other serious health 

effects or symptoms which could impair an individual’s ability to 

take protective action) = 20 ppm 

Description: Colorless-to-slightly yellow gas 

2 General Information • ATSDR 
 

 Hydrogen Chloride 

Warning properties: Sharp, choking odor. Air odor threshold is 

0.77 ppm, but only 50% of distracted exposed persons can 

perceive hydrogen chloride’s odor at 5 ppm. 

Molecular weight: 36.5 daltons
 

Boiling point (760 mm Hg): = -121 EF (-85 EC)
 

Freezing point: -174 EF (-114 EC)
 

Vapor pressure: 30,780 mm Hg at 68 EF (20 EC)
 

Gas density: 1.3 (air = 1)
 

Water solubility: 67% at 68 EF (20 EC)
 

Flammability: Not flammable
 

Incompatibilities	 Hydrogen chloride is highly corrosive to most metals. It also 

reacts with hydroxides, amines, and alkalies. 

ATSDR • General Information 3 
 

Hydrogen Chloride 

4 General Information • ATSDR 
 

 Hydrogen Chloride 

Health Effects 

• Concentrated hydrogen chloride can be corrosive to the skin, eyes, nose, mucous 

membranes, and respiratory and gastrointestinal tracts. 

• Inhalation of hydrogen chloride can lead to pulmonary edema. Ingestion can cause 

severe injury to the mouth, throat, esophagus, and stomach. 

• Other effects of exposure include shock, circulatory collapse metabolic acidosis, and 

respiratory depression. 

Acute Exposure	 Hydrogen chloride is a strong mineral acid; its corrosive and 

irritant properties are the primary concern in both acute and 

chronic exposures. 

Children do not always respond to chemicals in the same way 

that adults do. Different protocols for managing their care may 

be needed. 

Respiratory	 Hydrogen chloride gas is intensely irritating to the mucous 

membranes of the nose, throat, and respiratory tract. Brief 

exposure to 35 ppm causes throat irritation, and levels of 50 to 

100 ppm are barely tolerable for 1 hour. The greatest impact is 

on the upper respiratory tract; exposure to high concentrations 

can rapidly lead to swelling and spasm of the throat and 

suffocation. 

Most seriously exposed persons have immediate onset of rapid 

breathing, blue coloring of the skin, and narrowing of the 

bronchioles. Patients who have massive exposures may develop 

an accumulation of fluid in the lungs. 

Exposure to hydrogen chloride can lead to Reactive Airway 

Dysfunction Syndrome (RADS), a chemically- or irritantinduced type of asthma. 

Children may be more vulnerable to corrosive agents than adults 

because of the relatively smaller diameter of their airways. 

Children may also be more vulnerable to gas exposure because 

of increased minute ventilation per kg and failure to evacuate an 

area promptly when exposed. 

Metabolic	 A rare and unusual complication of ingestion of high levels of 

hydrogen chloride is an increase in the concentration of chloride 

ions in the blood, causing an acid-base imbalance. 

ATSDR • Health Effects 5 
 

Hydrogen Chloride 

Dermal 

Ocular 

Gastrointestinal 

Cardiovascular 

Potential Sequelae 

Chronic Exposure 

Because of their higher metabolic rates, children may be more 

vulnerable to toxicants interfering with basic metabolism. 

Deep burns of the skin and mucous membranes are caused by 

contact with concentrated hydrochloric acid or hydrogen 

chloride gas; disfiguring scars may result. Contact with less 

concentrated acid or with vapor or mist can cause redness of the 

skin and mild inflammation. 

Because of their relatively larger surface area:body weight ratio, 

children are more vulnerable to toxicants affecting the skin. 

Exposure of the eyes to concentrated hydrogen chloride vapor 

or hydrochloric acid can cause corneal cell death, cataracts, and 

glaucoma. Exposure to dilute solutions can cause stinging pain 

and injuries such as ulcers of the eye surface. 

Ingesting concentrated hydrochloric acid can cause pain, 

difficulty swallowing, nausea, and vomiting. 

Ingestion of concentrated hydrochloric acid can also cause 

severe corrosive injury to the mouth, throat esophagus, and 

stomach, with bleeding, perforation, scarring, or stricture 

formation as potential sequelae. 

Ingestion of concentrated hydrochloric acid or massive skin 

exposure to either hydrochloric acid or hydrogen chloride gas 

may cause low blood pressure as a result of gastrointestinal 

bleeding or fluid displacement. After acute exposure, pulmonary 

function generally returns to baseline in 7 to 14 days. 

Although complete recovery is usual, symptoms and prolonged 

pulmonary deficits can persist. Patients may develop Reactive 

Airways Dysfunction Syndrome (RADS). 

Patients who have ingested hydrochloric acid may experience 

scarring of the esophagus or stomach, which can cause 

narrowing, difficulty swallowing, or gastric outlet obstruction. 

Chronic or prolonged exposure to hydrogen chloride gas (above 

the OSHA PEL) or to mist has been associated with changes in 

pulmonary function, chronic inflammation of the bronchi, nasal 

ulceration, and symptoms resembling acute viral infection of the 

upper respiratory tract as well as inflammation of the skin, 

discoloration and erosion of dental enamel, and inflammation of 

the eye membrane. 

6 Health Effects • ATSDR 
 

 Hydrogen Chloride 

Carcinogenicity Hydrogen chloride has not been classified for carcinogenic 

effects. 

Reproductive and 

Developmental Effects The reproductive hazards of hydrogen chloride to humans are 

unknown. Few studies have been directed at reproductive effects 

in experimental animals exposed to hydrogen chloride. No data 

were located pertaining to maternal transfer of hydrogen chloride 

through the placenta or in breast milk Hydrogen chloride is not 

included in Reproductive and Developmental Toxicants, a 1991 

report published by the U.S. General Accounting Office (GAO) 

that lists 30 chemicals of concern because of widely 

acknowledged reproductive and developmental consequences. 

ATSDR • Health Effects 7 
 

Hydrogen Chloride 

8 Health Effects • ATSDR 
 

 Hydrogen Chloride 

Prehospital Management 

C Victims exposed only to hydrogen chloride gas and whose skin and clothing appear 

dry do not pose risks of secondary contamination to rescuers. However, victims 

exposed to hydrochloric acid or hydrogen chloride whose clothing or skin is moist or 

wet can secondarily contaminate response personnel by direct contact or through offgassing vapor. 

C High concentrations of hydrogen chloride can cause corrosive injury to all exposed 

body tissues. When inhaled, it can result in upper respiratory tract irritation, leading 

to laryngeal edema, laryngeal spasm, and asphyxia. Concentrated hydrochloric acid 

causes similar corrosive injury to the skin and, if ingested, can cause severe corrosive 

injury to the mouth, throat, esophagus, and stomach. 

C There is no antidote for hydrogen chloride poisoning. Treatment consists of support 

of respiratory and cardiovascular functions. 

Hot Zone Rescuers should be trained and appropriately attired before 

entering the Hot Zone. If the proper equipment is not available, 

or if rescuers have not been trained in its use, assistance should 

be obtained from a local or regional HAZMAT team or other 

properly equipped response organization. 

Rescuer Protection Hydrogen chloride gas is a severe respiratory-tract and skin 

irritant that forms a strong acid (hydrochloric acid) on contact 

with water. 

Respiratory Protection: Positive-pressure, self-contained 

breathing apparatus (SCBA) is recommended in response 

situations that involve exposure to potentially unsafe levels of 

hydrogen chloride. 

Skin Protection: Chemical-protective clothing is recommended 

because hydrogen chloride can cause skin irritation and burns. 

ABC Reminders Quickly access for a patent airway, ensure adequate respiration 

and pulse. If trauma is suspected, maintain cervical 

immobilization manually and apply a cervical collar and a 

backboard when feasible. 

Victim Removal If victims can walk, lead them out of the Hot Zone to the 

Decontamination Zone. Victims who are unable to walk may be 

removed on backboards or gurneys; if these are not available, 

carefully carry or drag victims to safety. 

ATSDR • Prehospital Management 9 
 

Hydrogen Chloride 

Decontamination Zone 

Rescuer Protection 

ABC Reminders 

Basic Decontamination 

Transfer to Support Zone 

10 Prehospital Management • ATSDR 

Consider appropriate management of chemically contaminated 

children, such as measures to reduce separation anxiety if a child 

is separated from a parent or other adult. 

Victims exposed only to hydrogen chloride gas who have no skin 

or eye irritation do not need decontamination; they may be 

transferred immediately to the Support Zone. All others require 

decontamination as described below. 

If exposure levels are determined to be safe, decontamination 

may be conducted by personnel wearing a lower level of 

protection than that worn in the Hot Zone (described above). 

Quickly access for a patent airway, ensure adequate respiration 

and pulse. Stabilize the cervical spine with a collar and a 

backboard if trauma is suspected. Administer supplemental 

oxygen as required. Assist ventilation with a bag-valve-mask 

device if necessary. 

Victims who are able may assist with their own decontamination. 

Remove contaminated clothing while flushing exposed skin and 

hair with water for 3 to 5 minutes, wash thoroughly with soap 

and water. Use caution to avoid hypothermia when 

decontaminating children or the elderly. Use blankets or warmers 

when appropriate. Double-bag contaminated clothing and 

personal belongings. 

Flush exposed or irritated eyes with tepid plain water or saline 

for 15 minutes. Eye irrigation should be carried out 

simultaneously with other basic care and transport. Remove 

contact lenses if easily removable without additional trauma to 

the eye. 

In cases of ingestion, do not induce emesis. Do not administer 

activated charcoal or attempt to neutralize stomach 

contents. Victims who are conscious and able to swallow should 

be given 4 to 8 ounces of water or milk. (Children’s dose is 2 to 

4 ounces.) 

Consider appropriate management of chemically contaminated 

children, such as measures to reduce separation anxiety if a child 

is separated from a parent or other adult. If possible, seek 

assistance from a child separation expert. 

As soon as basic decontamination is complete, move the victim 

to the Support Zone. 
 

 Hydrogen Chloride 

Support Zone 

ABC Reminders 

Additional Decontamination 

Advanced Treatment 

Be certain that victims have been decontaminated properly (see 

Decontamination Zone above). Victims who have undergone 

decontamination or who have been exposed only to gas and who 

have no symptoms of skin or eye irritation pose no serious risk 

of secondary contamination. In such cases, Support Zone 

personnel require no specialized protective gear. 

Quickly access for a patent airway. If trauma is suspected, 

maintain cervical immobilization manually and apply a cervical 

collar and a backboard when feasible. Ensure adequate 

respiration and pulse. Administer supplemental oxygen as 

required and establish intravenous access if necessary. Place on 

a cardiac monitor. 

Continue irrigating exposed skin and eyes, as appropriate. 

In cases of ingestion, do not induce emesis. Do not administer 

activated charcoal or attempt to neutralize stomach 

contents. Adult victims who are conscious and able to swallow 

should be given 4 to 8 ounces of water or milk, if it has not been 

given previously, to flush residual acid from the esophagus and 

to dilute stomach contents. Children should receive half of the 

adult dose. 

In cases of respiratory compromise secure airway and respiration 

via endotracheal intubation. If not possible, perform 

cricothyroidotomy if equipped and trained to do so. 

Treat patients who have bronchospasm with aerosolized 

bronchodilators. The use of bronchial sensitizing agents in 

situations of multiple chemical exposures may pose additional 

risks. Consider the health of the myocardium before choosing 

which type of bronchodilator should be administered. Cardiac 

sensitizing agents may be appropriate; however, the use of 

cardiac sensitizing agents after exposure to certain chemicals 

may pose enhanced risk of cardiac arrhythmias (especially in the 

elderly). Sympathomimetic bronchodilators generally will reverse 

bronchospasm in patients exposed to hydrogen chloride. 

Consider racemic epinephrine aerosol for children who develop 

stridor. Dose 0.25–0.75 mL of 2.25% racemic epinephrine 

solution in 2.5 cc water, repeat every 20 minutes as needed, 

cautioning for myocardial variability. 

Patients who are comatose, hypotensive, or are having seizures 

or cardiac arrhythmias should be treated according to advanced 

life support (ALS) protocols. 

ATSDR • Prehospital Management 11 
 

Hydrogen Chloride 

Transport to Medical Facility	 Only decontaminated patients or patients not requiring 

decontamination should be transported to a medical facility. 

“Body bags” are not recommended. 

Report to the base station and the receiving medical facility the 

condition of the patient, treatment given, and estimated time of 

arrival at the medical facility. 

If hydrochloric acid has been ingested, prepare the ambulance in 

case the victim vomits toxic material. Have ready several towels 

and open plastic bags to quickly clean up and isolate vomitus. 

Multi-Casualty Triage	 Consult with the base station physician or the regional poison 

control center for advice regarding triage of multiple victims. 

Patients with evidence of significant exposure such as skin or eye 

irritation, pain, or breathing difficulties should be transported to 

a medical facility for evaluation. Others may be discharged from 

the scene after their names, addresses, and telephone numbers 

are recorded. Those discharged should be advised to seek 

medical care promptly if symptoms develop (see Patient 

Information Sheet below). 

12 Prehospital Management • ATSDR 
 

 Hydrogen Chloride 

Emergency Department Management 

C Patients exposed only to hydrogen chloride gas whose clothing and skin are dry do 

not pose a risk of secondary contamination. Hospital personnel can be secondarily 

contaminated by patients exposed to hydrochloric acid either by direct skin contact 

or through inhalation of vapor off-gassing from heavily soaked clothing or skin. 

Patients do not pose contamination risks after contaminated clothing is removed and 

the skin is washed. 

C High concentrations of hydrogen chloride causes corrosive injury to all exposed body 

tissues. When inhaled, it can result in upper respiratory tract irritation, leading to 

laryngeal edema, laryngeal spasm, and asphyxia. Concentrated hydrochloric acid 

causes similar corrosive injuries to exposed tissues and, if ingested, can cause severe 

corrosive injury to the mouth, throat, esophagus, and stomach. 

C There is no antidote for hydrogen chloride poisoning. Treatment consists of support 

of respiratory and cardiovascular functions. 

Decontamination Area	 Previously decontaminated patients and patients exposed only to 

hydrogen chloride gas who have no skin or eye irritation may be 

transferred immediately to the Critical Care Area. Others require 

decontamination as described below. 

Hospital personnel should don rubber gloves, rubber aprons, and 

eye protection before treating patients who are wet with 

hydrochloric acid. 

Be aware that use of protective equipment by the provider may 

cause fear in children, resulting in decreased compliance with 

further management efforts. 

Because of their relatively larger surface area:body weight ratio, 

children are more vulnerable to toxicants affecting the skin. Also, 

emergency room personnel should examine children’s mouths 

because of the frequency of hand-to-mouth activity among 

children. 

ABC Reminders	 Evaluate and support airway, breathing, and circulation. Children 

may be more vulnerable to corrosive agents than adults because 

of the smaller diameter of their airways. In cases of respiratory 

compromise secure airway and respiration via endotracheal 

intubation. If not possible, surgically create an airway. 

Treat patients who have bronchospasm with aerosolized 

bronchodilators. The use of bronchial sensitizing agents in 

ATSDR • Emergency Department Management 13 
 

Hydrogen Chloride 

Basic Decontamination 

Critical Care Area 

situations of multiple chemical exposures may pose additional 

risks. Consider the health of the myocardium before choosing 

which type of bronchodilator should be administered. Cardiac 

sensitizing agents may be appropriate; however, the use of 

cardiac sensitizing agents after exposure to certain chemicals 

may pose enhanced risk of cardiac arrhythmias (especially in the 

elderly). Hydrogen chloride poisoning is not known to pose 

additional risk during the use of bronchial or cardiac sensitizing 

agents. Sympathomimetic bronchodilators generally will reverse 

bronchospasm in patients exposed to hydrogen chloride. 

Consider racemic epinephrine aerosol for children who develop 

stridor. Dose 0.25–0.75 mL of 2.25% racemic epinephrine 

solution in 2.5 cc water, repeat every 20 minutes as needed, 

cautioning for myocardial variability. 

Patients who are comatose, hypotensive, or having seizures or 

cardiac arrhythmias should be treated in the conventional 

manner. 

Patients who are able may assist with their own decontamination. 

Remove and double-bag contaminated clothing and personal 

belongings. 

Flush exposed skin and hair with water for 3 to 5 minutes 

(preferably under a shower). Wash thoroughly with soap and 

water, rinse thoroughly with water. Use caution to avoid 

hypothermia when decontaminating children or the elderly. Use 

blankets or warmers when appropriate. 

Flush exposed eyes with plain water or saline for at least 

15 minutes. Remove contact lenses if easily removable without 

additional trauma to the eye. Continue irrigation while 

transporting the patient to the Critical Care Area. 

In cases of ingestion, do not induce emesis. Do not administer 

activated charcoal or attempt to neutralize stomach 

contents. If it has not been given previously, administer 4 to 

8 ounces of water or milk to adults to flush residual acid from 

the esophagus and to dilute stomach contents. (Children’s dose 

is 2 to 4 ounces.) 

Be certain that appropriate decontamination has been carried out 

(see Decontamination Area above). 

14 Emergency Department Management • ATSDR 
 

 Hydrogen Chloride 

ABC Reminders 

Inhalation Exposure 

Skin Exposure 

Evaluate and support airway, breathing, and circulation as in 

ABC Reminders above. Children may be more vulnerable to 

corrosive agents than adults because of the relatively smaller 

diameter of their airways. Establish intravenous access in 

seriously ill patients if this has not been done previously. 

Continuously monitor cardiac rhythm. 

Patients who are comatose, hypotensive, or have seizures or 

cardiac arrhythmias should be treated in the conventional 

manner. 

Administer supplemental oxygen by mask to patients who have 

respiratory symptoms. Treat patients who have bronchospasm 

with aerosolized bronchodilators. The use of bronchial 

sensitizing agents in situations of multiple chemical exposures 

may pose additional risks. Consider the health of the 

myocardium before choosing which type of bronchodilator 

should be administered. Cardiac sensitizing agents may be 

appropriate; however, the use of cardiac sensitizing agents after 

exposure to certain chemicals may pose enhanced risk of cardiac 

arrhythmias (especially in the elderly). Sympathomimetic 

bronchodilators generally will reverse bronchospasm in patients 

exposed to hydrogen chloride. 

Consider racemic epinephrine aerosol for children who develop 

stridor. Dose 0.25–0.75 mL of 2.25% racemic epinephrine 

solution in 2.5 cc water, repeat every 20 minutes as needed, 

cautioning for myocardial variability. 

Observe patients for at least 24 hours, repeating appropriate 

tests and chest examinations as needed. Follow-up as clinically 

indicated. 

Some authorities recommend treatment with high doses of 

corticosteroids for patients who have high-dose exposures, but 

the value of this treatment is questionable and unsupported by 

clinical studies. 

If the skin was in contact with concentrated hydrochloric acid or 

hydrogen chloride gas or mists, chemical burns may occur, treat 

as thermal burns. 

Because of their relatively larger surface area:body weight ratio, 

children are more vulnerable to toxicants affecting the skin. 

ATSDR • Emergency Department Management 15 
 

Hydrogen Chloride 

Eye Exposure 

Ingestion Exposure 

Antidotes and 

Other Treatments 

Laboratory Tests 

Continue irrigating for at least 15 minutes or until the pH of the 

conjunctival fluid has returned to normal. Test visual acuity. 

Examine eyes for corneal damage and treat appropriately. 

Immediately consult an ophthalmologist for patients who have 

corneal injuries. 

Do not induce emesis. Do not administer activated charcoal 

or attempt to neutralize stomach contents. Immediate dilution 

with 4 to 8 ounces of water or milk may be beneficial (pediatric 

dose 2 to 4 ounces) for alert patients who can swallow. 

Consider endoscopy to evaluate the extent of gastrointestinal 

tract injury. Extreme throat swelling may require endotracheal 

intubation or cricothyroidotomy. Gastric lavage is useful in 

certain circumstances to remove caustic material and prepare for 

endoscopic examination. Consider gastric lavage with a small 

nasogastric tube if: (1) a large dose has been ingested; (2) the 

patient’s condition is evaluated within 30 minutes; (3) the patient 

has oral lesions or persistent esophageal discomfort; and (4) the 

lavage can be administered within 1 hour of ingestion. Care must 

be taken when placing the gastric tube because blind gastric-tube 

placement may further injure the chemically damaged esophagus 

or stomach. 

Because children do not ingest large amounts of corrosive 

materials, and because of the risk of perforation from NG 

intubation, lavage is discouraged in children unless performed 

under endoscopic guidance. 

Toxic vomitus or gastric washings should be isolated (e.g., by 

attaching the lavage tube to isolated wall suction or another 

closed container). 

The use of corticosteroids to prevent acid-induced strictures is 

questionable and unsupported by clinical studies. 

There is no antidote for hydrogen chloride poisoning. 

The diagnosis of acute hydrogen chloride toxicity is primarily 

clinical, based on symptoms of the corrosive action of the gas or 

acid. Routine laboratory studies for all exposed patients include 

CBC, glucose, and electrolyte determinations. Monitor acid-base 

status in patients who have ingested hydrochloric acid. If 

respiratory-tract irritation is present, monitor with chest 

radiography and pulse oximetry (or ABG measurements). 

16 Emergency Department Management • ATSDR 
 

 Hydrogen Chloride 

Disposition and 

Follow-up 

Delayed Effects 

Patient Release 

Follow-up 

Reporting 

There is no biologic test specific for systemically absorbed 

hydrogen chloride. 

Patients who develop serious signs or symptoms of hydrogen 

chloride exposure should be hospitalized and observed closely 

for 4 to 6 hours or until asymptomatic. 

Delayed effects are unlikely in patients who have minor 

symptoms that resolve quickly. However, symptoms can be 

delayed for 1 to 2 days. 

Patients who have had minor exposure and who are 

asymptomatic 4 to 6 hours after exposure may be discharged and 

advised to seek medical care promptly if symptoms develop (see 

the Hydrogen Chloride—Patient Information Sheet below). 

Obtain the name of the patient’s primary care physician so that 

the hospital can send a copy of the ED visit to the patient’s 

doctor. 

Patients who have inhaled significant amounts of hydrogen 

chloride should be monitored with pulmonary function tests. 

Patients should also be monitored for the development of 

Reactive Airway Dysfunction Syndrome (RADS), a chemicallyor irritant-induced type of asthma. About 2 to 4 weeks after an 

ingestion, consider follow-up esophagoscopy and an upper 

gastrointestinal tract series to evaluate secondary scarring or 

stricture formation. 

Patients who have skin or corneal injury should be re-examined 

within 24 hours. 

If a work-related incident has occurred, you may be legally 

required to file a report; contact your state or local health 

department. 

Other persons may still be at risk in the setting where this 

incident occurred. If the incident occurred in the workplace, 

discussing it with company personnel may prevent future 

incidents. If a public health risk exists, notify your state or local 

health department or other responsible public agency. When 

appropriate, inform patients that they may request an evaluation 

of their workplace from OSHA or NIOSH. See Appendices III 

and IV for a list of agencies that may be of assistance. 

ATSDR • Emergency Department Management 17 
 

Hydrogen Chloride 

18 Emergency Department Management • ATSDR 
 

 Hydrogen Chloride 

Hydrogen Chloride
 

Patient Information Sheet
 

This handout provides information and follow-up instructions for persons who have been exposed to 

hydrogen chloride gas or hydrochloric acid solution. 

What are hydrogen chloride and hydrochloric acid? 

Hydrogen chloride is a colorless to slightly yellow gas with a sharp, irritating odor. It forms a dense 

white vapor when it comes in contact with air. When hydrogen chloride dissolves in water, it forms 

hydrochloric acid also known as muriatic acid. Both hydrogen chloride and hydrochloric acid are 

corrosive and may cause burns on contact. Hydrogen chloride is not flammable. 

What immediate health effects can be caused by exposure to these chemicals? 

Hydrogen chloride gas can irritate the lungs, causing a cough and shortness of breath. Breathing high 

levels of the gas or vapor can lead to a build-up of fluid in the lungs, which may cause death. Because 

hydrochloric acid is corrosive, it can cause eye damage, even blindness, if splashed in the eyes. Skin 

contact can cause severe burns. Ingestion of concentrated hydrochloric acid can cause severe injury to 

the mouth, throat, esophagus and stomach. Generally, the more serious the exposure, the more severe 

the symptoms. 

Can hydrogen chloride or hydrochloric acid overexposure be treated? 

There is no antidote for poisoning due to these substances, but their effects can be treated and most 

exposed persons get well. People who have had serious exposures may need to be hospitalized. 

Are any future health effects likely to occur? 

A single, small exposure from which a person recovers quickly is not likely to cause delayed or longterm effects. Patients who breath a large amount of hydrogen chloride may develop permanent lung 

injury. If hydrochloric acid was swallowed, a patient may permanently have trouble swallowing. 

What tests can be done if a person has been exposed to hydrogen chloride? 

Specific tests for the presence of hydrogen chloride in blood or urine generally are not useful to the 

doctor. If a severe exposure has occurred, blood and urine analyses and other tests may show whether 

the lungs or stomach has been injured. Testing is not needed in every case. 

Where can more information about hydrogen chloride and hydrochloric acid be found? 

More information about hydrogen chloride and hydrochloric acid can be obtained from your regional 

poison control center; your state, county, or local health department; the Agency for Toxic Substances 

and Disease Registry (ATSDR); your doctor; or a clinic in your area that specializes in occupational and 

environmental health. If the exposure happened at work, you may wish to discuss it with your employer, 

the Occupational Safety and Health Administration (OSHA), or the National Institute for Occupational 

Safety and Health (NIOSH). Ask the person who gave you this form for help in locating these telephone 

numbers. 

ATSDR • Patient Information Sheet 19 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hydrogen Chloride 

Follow-up Instructions 

Keep this page and take it with you to your next appointment. Follow only the instructions checked below. 

[ ] Call your doctor or the Emergency Department if you develop any unusual signs or symptoms within the 

next 24 hours, especially: 

C coughing or wheezing 

C difficulty breathing, shortness of breath, or chest pain 

C stomach pain or vomiting 

C increased pain or a discharge from exposed eyes 

C	 increased redness or pain or a pus-like discharge in the area of a skin burn 

[ ] No follow-up appointment is necessary unless you develop any of the symptoms listed above. 

[ ] Call for an appointment with Dr. in the practice of . 

When you call for your appointment, please say that you were treated in the Emergency Department at 

Hospital by and were advised to be 

seen again in days. 

[ ] Return to the Emergency Department/ Clinic on (date) at 

AM/PM for a follow-up examination. 

[ ] Do not perform vigorous physical activities for 1 to 2 days. 

[ ] You may resume everyday activities including driving and operating machinery.
 

[ ] Do not return to work for days.
 

[ ] You may return to work on a limited basis. See instructions below.
 

[ ] Avoid exposure to cigarette smoke for 72 hours; smoke may worsen the condition of your lungs.
 

[ ] Avoid drinking alcoholic beverages for at least 24 hours; alcohol may worsen injury to your
 

stomach or have other effects. 

[ ] Avoid taking the following medications: 

[ ] You may continue taking the following medication(s) that your doctor(s) prescribed for you: 

[ ] Other instructions: 

•	 Provide the Emergency Department with the name and the number of your primary care physician so that 

the ED can send him or her a record of your emergency department visit. 

• You or your physician can get more information on the chemical by contacting: 

or , or by checking out the following Internet Web 

sites: ; . 

Signature of patient Date 

Signature of physician Date 

20 Patient Information Sheet • ATSDR