HYDROGEN CHLORIDE, ANHYDROUS

Diamond	Hazard	Value	Description
0 3 1	Health	3	Can cause serious or permanent injury.
	Flammability	0	Will not burn under typical fire conditions.
	Instability	1	Normally stable but can become unstable at elevated temperatures and pressures.
	Special

A colorless gas with a sharp, pungent odor. Fumes strongly in moist air. Nonflammable. Corrosive to metals and tissues and irritating to the eyes and respiratory system. Heavier than air. Long-term inhalation of low concentrations or short-term inhalation of high concentrations has adverse health effects. Prolonged exposure to fire or intense heat may result in the violent rupture and rocketing of the container. Used in the manufacture of rubber, pharmaceuticals, chemicals, and in gasoline refining and metals processing.

Rate of onset: Immediate

Persistence: Minutes to hours

Odor threshold: 0.77 ppm

Source/use/other hazard: Ore, other metal refining/cleaning; food/pickling; petroleum; corrosive liq.

• Known Catalytic Activity
• Water-Reactive

Fumes strongly in moist air, generating corrosive hydrochloric acid vapors. Soluble in water with evolution of heat.

Fire may produce irritating or poisonous gases. Containers may explode in heat of fire. At high temperatures, it decomposes into hydrogen and chlorine. The following materials should be avoided: Mercuric sulfate -- violent reaction with gaseous hydrochloric acid at 250F. Sodium -- reacts vigorously with gaseous hydrochloric acid. Acetic anhydride, 2-aminoethanol, ammonium hydroxide, chlorosulfonic acid, ethylene diamine, ethyleneimine, oleum, propiolactone, sodium hydroxide, sulfuric acid, and vinyl acetate -- increase in temperature and pressure when mixed with hydrochloric acid. Calcium phosphide -- energetic reaction with hydrochloric acid. Silver perchlorate and carbon tetrachloride -- when mixed in combination with hydrochloric acid forms a compound that detonates at 105F. Formaldehyde -- when mixed with hydrochloric acid forms a human carcinogen. Material reacts violently with bases and is corrosive with the generation of heat. Reacts with base metals, forming combustible gas (hydrogen). Reacts violently with strong oxidants forming toxic gas (chlorine). Avoid heat; at high temperatures it will decompose into hydrogen and chlorine. (EPA, 1998)

Gas concentrations of 50 to 100 ppm are tolerable for 1 hour. Concentrations of 1,000 to 2,000 ppm are dangerous, even for brief exposures. More severe exposures will result in serious respiratory distress and prolonged exposures will result in death. Mists of hydrochloric acid are considered less harmful than anhydrous hydrochloric acid, because droplets have no dehydrating action. Individuals with respiratory problems and digestive diseases may be adversely affected by low level exposures to the gas or mist. (EPA, 1998)

HYDROGEN CHLORIDE, ANHYDROUS is an anhydrous (no water) strong acid. Reacts rapidly and exothermically with bases of all kinds (including amines and amides). Reacts exothermically with carbonates (including limestone and building materials containing limestone) and hydrogen carbonates to generate carbon dioxide. Reacts with sulfides, carbides, borides, and phosphides to generate toxic or flammable gases. Reacts with many metals (including aluminum, zinc, calcium, magnesium, iron, tin and all of the alkali metals) to generate flammable hydrogen gas. Reacts violently with acetic anhydride, 2-aminoethanol, ammonium hydroxide, calcium phosphide, chlorosulfonic acid, 1,1-difluoroethylene, ethylenediamine, ethyleneimine, oleum, perchloric acid, b-propiolactone, propylene oxide, silver perchlorate/carbon tetrachloride mixture, sodium hydroxide, uranium(IV) phosphide, vinyl acetate, calcium carbide, rubidium carbide, cesium acetylide, rubidium acetylide, magnesium boride, mercury(II) sulfate [Lewis]. Undergoes a very energetic reaction with calcium phosphide [Mellor 8:841(1946-1947)]. Corrosive to metals and tissues and irritating to the eyes and respiratory system. Corrodes galvanized or copper-alloy metals (brass, bronze); fittings of stainless steel or mild or cast steel must therefore be used. Reacts with calcium carbide with incandescence [Mellor 5:862(1946-1947]. Absorption on mercuric sulfate becomes violent at 125°C. [Mellor 2, Supp. 1:462(1956)].

• Acids, Strong Non-oxidizing

No information available.

Excerpt from ERG Guide 125 [Gases - Toxic and/or Corrosive]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 100 meters (330 feet) in all directions.

SPILL: See ERG Tables 1 and 3 - Initial Isolation and Protective Action Distances on the UN/NA 1050 datasheet.

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 1600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions. (ERG, 2024)

Wear self-contained breathing apparatus and full protective clothing. Neutralize with chemically basic substances such as soda ash or slaked lime.

Normal fire fighting procedures may be used. Do not get water inside containers. Move containers from fire area. Keep containers that are exposed to the fire cool with water that is sprayed from the side until well after the fire is out. (EPA, 1998)

Excerpt from ERG Guide 125 [Gases - Toxic and/or Corrosive]:

Do not touch or walk through spilled material. Stop leak if you can do it without risk. If possible, turn leaking containers so that gas escapes rather than liquid. Prevent entry into waterways, sewers, basements or confined areas. Do not direct water at spill or source of leak. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Isolate area until gas has dispersed. (ERG, 2024)

Excerpt from NIOSH Pocket Guide for Hydrogen chloride:

Skin:
• PREVENT SKIN CONTACT (SOLUTION) - If this chemical is in solution, wear appropriate personal protective clothing to prevent skin contact.
• FROSTBITE - Compressed gases may create low temperatures when they expand rapidly. Leaks and uses that allow rapid expansion may cause a frostbite hazard. Wear appropriate personal protective clothing to prevent the skin from becoming frozen.

Eyes:
• PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact.
• FROSTBITE - Wear appropriate eye protection to prevent eye contact with the liquid that could result in burns or tissue damage from frostbite.

Wash skin: WHEN CONTAMINATED (SOLUTION) - If this chemical is in solution, the worker should immediately wash the skin when it becomes contaminated.

Remove: WHEN WET OR CONTAMINATED (SOLUTION) - If this chemical is in solution, work clothing that becomes wet or significantly contaminated should be removed and replaced.

Change: No recommendation is made specifying the need for the worker to change clothing after the workshift.

Provide:
• EYEWASH (SOLUTION) - Eyewash fountains should be provided (when this chemical is in solution) in areas where there is any possibility that workers could be exposed to the substances; this is irrespective of the recommendation involving the wearing of eye protection.
• QUICK DRENCH (SOLUTION) - Facilities for quickly drenching the body should be provided (when this chemical is in solution) within the immediate work area for emergency use where there is a possibility of exposure. [Note: It is intended that these facilities provide a sufficient quantity or flow of water to quickly remove the substance from any body areas likely to be exposed. The actual determination of what constitutes an adequate quick drench facility depends on the specific circumstances. In certain instances, a deluge shower should be readily available, whereas in others, the availability of water from a sink or hose could be considered adequate.]
• FROSTBITE WASH - 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. (NIOSH, 2024)

Normalized Breakthrough Times (in Minutes)

Chemical	CAS Number	State	QS	QC	SL	C3	TF	TP	RC	TK	RF
Hydrochloric acid (37%)	7647-01-0	Liquid	54	140	>480	>480	>480	>480	>480	>480	>480
Hydrogen chloride (-90°C, liquid)	7647-01-0	Liquid								>180
Hydrogen chloride (gaseous)	7647-01-0	Vapor		imm	>480	>480	>480	>480	>480	>480	>480

Special Warning from DuPont: Tychem® and Tyvek® fabrics should not be used around heat, flames, sparks or in potentially flammable or explosive environments. Only...

(DuPont, 2024)

Warning: Hydrogen chloride is extremely corrosive. Caution is advised.

Signs and Symptoms of Acute Hydrogen Chloride Exposure: Signs and symptoms of acute ingestion of hydrogen chloride may be severe and include salivation, intense thirst, difficulty in swallowing, chills, pain, and shock. Oral, esophageal, and stomach burns are common. Vomitus generally has a coffee-ground appearance. The potential for circulatory collapse is high following ingestion of hydrogen chloride. Acute inhalation exposure of hydrogen chloride may result in sneezing, hoarseness, choking, laryngitis, and respiratory tract irritation. Bleeding of nose and gums, ulceration of the nasal and oral mucosa, bronchitis, pneumonia, dyspnea (shortness of breath), chest pain, and pulmonary edema may also occur. If the eyes have come in contact with hydrogen chloride, irritation, pain, swelling, corneal erosion, and blindness may result. Dermal exposure may result in dermatitis (red, inflamed skin), severe burns, and pain.

Emergency Life-Support Procedures: Acute exposure to hydrogen chloride may require decontamination and life support for the victims. Emergency personnel should wear protective clothing appropriate to the type and degree of contamination. Air-purifying or supplied-air respiratory equipment should also be worn, as necessary. Rescue vehicles should carry supplies such as plastic sheeting and disposable plastic bags to assist in preventing spread of contamination.

Inhalation Exposure:
1. Move victims to fresh air. Emergency personnel should avoid self-exposure to hydrogen chloride.
2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support.
3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
4. RUSH to a health care facility.

Dermal/Eye Exposure:
1. Remove victims from exposure. Emergency personnel should avoid self- exposure to hydrogen chloride.
2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support.
3. Remove contaminated clothing as soon as possible.
4. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes.
5. Wash exposed skin areas THOROUGHLY with soap and water.
6. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
7. RUSH to a health care facility.

Ingestion Exposure:
1. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support.
2. DO NOT induce vomiting or attempt to neutralize!
3. Rinse mouth with large amounts of water. Victims should not attempt to swallow this water.
4. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
5. Activated charcoal is of no value.
6. Give the victims water or milk: children up to 1 year old, 125 mL (4 oz or 1/2 cup); children 1 to 12 years old, 200 mL (6 oz or 3/4 cup); adults, 250 mL (8 oz or 1 cup). Water or milk should be given only if victims are conscious and alert.
7. RUSH to a health care facility. (EPA, 1998)

• ANHYDROUS HYDROCHLORIC ACID
• ANHYDROUS HYDROGEN CHLORIDE
• CHLOROHYDRIC ACID
• HYDROCHLORIC ACID
• HYDROCHLORIC ACID (AEROSOL FORMS ONLY)
• HYDROCHLORIC ACID GAS
• HYDROCHLORIC ACID, ANHYDROUS
• HYDROCHLORIC ACID, TRIMER
• HYDROGEN CHLORIDE
• HYDROGEN CHLORIDE (ANHYDROUS)
• HYDROGEN CHLORIDE (GAS ONLY)
• HYDROGEN CHLORIDE (HYDROCHLORIC ACID)
• HYDROGEN CHLORIDE DIMER
• HYDROGEN CHLORIDE(GAS ONLY)
• HYDROGEN CHLORIDE, ANHYDROUS
• HYDROGEN CHLORIDE, [ANHYDROUS]
• MURIATIC ACID
• SPIRITS OF SALT