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Chemical Datasheet

HYDROGEN CHLORIDE, ANHYDROUS

2.3 - Poisonous gas 8 - Corrosive
Chemical Identifiers | Hazards | Response Recommendations | Physical Properties | Regulatory Information | Alternate Chemical Names

Chemical Identifiers

The Chemical Identifier fields include common identification numbers, the NFPA diamond U.S. Department of Transportation hazard labels, and a general description of the chemical. The information in CAMEO Chemicals comes from a variety of data sources.
CAS Number UN/NA Number DOT Hazard Label USCG CHRIS Code
  • 7647-01-0   (HYDROGEN CHLORIDE)
  • Poison Gas
  • Corrosive
NIOSH Pocket Guide International Chem Safety Card
Hydrogen chlorideexternal_link
NFPA 704
Diamond Hazard Value Description
0
3 1
Blue Health 3 Can cause serious or permanent injury.
Red Flammability 0 Will not burn under typical fire conditions.
Yellow Instability 1 Normally stable but can become unstable at elevated temperatures and pressures.
White Special
(NFPA, 2010)
General Description
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.

Hazards

The Hazard fields include special hazard alerts air and water reactions, fire hazards, health hazards, a reactivity profile, and details about reactive groups assignments and potentially incompatible absorbents. The information in CAMEO Chemicals comes from a variety of data sources.
Reactivity Alerts
Air & Water Reactions
Fumes strongly in moist air, generating corrosive hydrochloric acid vapors. Soluble in water with evolution of heat.
Fire Hazard
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)
Health Hazard
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)
Reactivity Profile
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)].
Belongs to the Following Reactive Group(s)
Potentially Incompatible Absorbents

No information available.

Response Recommendations

The Response Recommendation fields include isolation and evacuation distances, as well as recommendations for firefighting, non-fire response, protective clothing, and first aid. The information in CAMEO Chemicals comes from a variety of data sources.
Isolation and Evacuation
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)
Firefighting
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)
Non-Fire Response
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)
Protective Clothing
Excerpt from NIOSH Pocket Guide for Hydrogen chlorideexternal link:

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)
DuPont Tychem® Suit Fabrics
Tychem® Fabric Legend
QS = Tychem 2000 SFR
QC = Tychem 2000
SL = Tychem 4000
C3 = Tychem 5000
TF = Tychem 6000
TP = Tychem 6000 FR
RC = Tychem RESPONDER® CSM
TK = Tychem 10000
RF = Tychem 10000 FR
Testing Details
The fabric permeation data was generated for DuPont by a third party laboratory. Permeation data for industrial chemicals is obtained per ASTM F739. Normalized breakthrough times (the time at which the permeation rate exceeds 0.1 μg/cm2/min) are reported in minutes. All chemicals have been tested between approximately 20°C and 27°C unless otherwise stated. All chemicals have been tested at a concentration of greater than 95% unless otherwise stated.
Chemical warfare agents (Lewisite, Sarin, Soman, Sulfur Mustard, Tabun and VX Nerve Agent) have been tested at 22°C and 50% relative humidity per military standard MIL-STD-282. "Breakthrough time" for chemical warfare agents is defined as the time when the cumulative mass which permeated through the fabric exceeds the limit in MIL-STD-282 [either 1.25 or 4.0 μg/cm2].
A Caution from DuPont
This information is based upon technical data that DuPont believes to be reliable on the date issued. It is subject to revision as additional knowledge and experience are gained. The information reflects laboratory performance of fabrics, not complete garments, under controlled conditions. It is intended for informational use by persons having technical skill for evaluation under their specific end-use conditions, at their own discretion and risk. It is the user's responsibility to determine the level of toxicity and the proper personal protective equipment needed. Anyone intending to use this information should first verify that the garment selected is suitable for the intended use. In many cases, seams and closures have shorter breakthrough times and higher permeation rates than the fabric. If fabric becomes torn,abraded or punctured, or if seams or closures fail, or if attached gloves, visors, etc. are damaged, end user should discontinue use of garment to avoid potential exposure to chemical. Since conditions of use are outside our control, DuPont makes no warranties, express or implied, including, without limitation, no warranties of merchantability or fitness for a particular use and assume no liability in connection with any use of this information. This information is not intended as a license to operate under or a recommendation to infringe any patent, trademark or technical information of DuPont or others covering any material or its use.
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
> indicates greater than.
"imm" indicates immediate; having a normalized breakthrough time of 10 minutes or less.

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

...Tychem® ThermoPro, Tychem® Reflector® and Tychem® TK styles 600T/601T (with aluminized outer suit) garments are designed and tested to help reduce burn injury during escape from a flash fire. Users of Tychem® ThermoPro, Tychem® Reflector® and Tychem® TK styles 600T/601T (with aluminized outer suit) garments should not knowingly enter an explosive environment. Tychem® garments with attached socks must be worn inside protective outer footwear and are not suitable as outer footwear. These attached socks do not have adequate durability or slip resistance to be worn as the outer foot covering.

(DuPont, 2024)

First Aid
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)

Physical Properties

The Physical Property fields include properties such as vapor pressure and boiling point, as well as explosive limits and toxic exposure thresholds The information in CAMEO Chemicals comes from a variety of data sources.

Note: For Vapor Density and Specific Gravity, comparing the value to 1.0 can tell you if the chemical will likely sink/rise in air or sink/float in fresh water (respectively). Short phrases have been added to those values below as an aid. However, make sure to also consider the circumstances of a release. The Vapor Density comparisons are only valid when the gas escaping is at the same temperature as the surrounding air itself. If the chemical is escaping from a container where it was pressurized or refrigerated, it may first escape and behave as a heavy gas and sink in the air (even if it has a Vapor Density value less than 1). Also, the Specific Gravity comparisons are for fresh water (density 1.0 g/mL). If your spill is in salt water (density about 1.027 g/mL), you need to adjust the point of comparison. There are some chemicals that will sink in fresh water and float in salt water.
Chemical Formula:
  • HCl
Flash Point: data unavailable
Lower Explosive Limit (LEL): Not combustible. (EPA, 1998)
Upper Explosive Limit (UEL): Not combustible. (EPA, 1998)
Autoignition Temperature: Not flammable (USCG, 1999)
Melting Point: -174.6°F (Melting point is -13.7°F for a 39.17% weight/weight solution.) (EPA, 1998)
Vapor Pressure: 32452 mmHg at 70°F ; 760 mmHg at -120.6°F (NTP, 1992)
Vapor Density (Relative to Air): 1.268 (EPA, 1998) - Heavier than air; will sink
Specific Gravity: 1.05 at 59°F for 10.17% weight/weight solution (EPA, 1998) - Denser than water; will sink
Boiling Point: -121°F at 760 mmHg (A constant boiling azeotrope with water containing 20.22% hydrogen chloride boils at 227°F.) (EPA, 1998)
Molecular Weight: 36.46 (EPA, 1998)
Water Solubility: 82.3 g/100 g at 32°F (NTP, 1992)
Ionization Energy/Potential: 12.74 eV (NIOSH, 2024)
IDLH: 50 ppm (NIOSH, 2024)

AEGLs (Acute Exposure Guideline Levels)

Final AEGLs for Hydrogen chloride (7647-01-0)
Exposure Period AEGL-1 AEGL-2 AEGL-3
10 minutes 1.8 ppm 100 ppm 620 ppm
30 minutes 1.8 ppm 43 ppm 210 ppm
60 minutes 1.8 ppm 22 ppm 100 ppm
4 hours 1.8 ppm 11 ppm 26 ppm
8 hours 1.8 ppm 11 ppm 26 ppm
(NAC/NRC, 2024)

ERPGs (Emergency Response Planning Guidelines)

Chemical ERPG-1 ERPG-2 ERPG-3
Hydrogen Chloride (7647-01-0) 3 ppm star-in-circle icon indicates that odor should be detectable near ERPG-1. 20 ppm 150 ppm
star-in-circle icon indicates that odor should be detectable near ERPG-1.
(AIHA, 2022)

PACs (Protective Action Criteria)

Chemical PAC-1 PAC-2 PAC-3
Hydrogen chloride; (Hydrochloric acid) (7647-01-0) 1.8 ppm 22 ppm 100 ppm
(DOE, 2024)

Regulatory Information

The Regulatory Information fields include information from the U.S. Environmental Protection Agency's Title III Consolidated List of Lists, the U.S. Cybersecurity and Infrastructure Security Agency's Chemical Facility Anti-Terrorism Standards, and the U.S. Occupational Safety and Health Administration's Process Safety Management of Highly Hazardous Chemicals Standard List (see more about these data sources).

EPA Consolidated List of Lists

Regulatory Name CAS Number/
313 Category Code
EPCRA 302
EHS TPQ
EPCRA 304
EHS RQ
CERCLA RQ EPCRA 313
TRI
RCRA
Code
CAA 112(r)
RMP TQ
Hydrochloric acid 7647-01-0 5000 pounds
Hydrochloric acid (aerosol forms only) 7647-01-0 5000 pounds 313
Hydrochloric acid (conc 37% or greater) 7647-01-0 5000 pounds 15000 pounds
Hydrogen chloride (anhydrous) 7647-01-0 500 pounds 5000 pounds 5000 pounds X 5000 pounds
Hydrogen chloride (gas only) 7647-01-0 500 pounds 5000 pounds 5000 pounds X 5000 pounds

(EPA List of Lists, 2024)

CISA Chemical Facility Anti-Terrorism Standards (CFATS)

RELEASE THEFT SABOTAGE
Chemical of Interest CAS Number Min Conc STQ Security
Issue
Min Conc STQ Security
Issue
Min Conc STQ Security
Issue
Hydrochloric acid (conc. 37% or greater) 7647-01-0 37.00 % 15000 pounds toxic
Hydrogen chloride (anhydrous) 7647-01-0 1.00 % 5000 pounds toxic ACG 500 pounds WME

(CISA, 2007)

OSHA Process Safety Management (PSM) Standard List

Chemical Name CAS Number Threshold Quantity (TQ)
Hydrochloric Acid, Anhydrous 7647-01-0 5000 pounds
Hydrogen Chloride 7647-01-0 5000 pounds

(OSHA, 2019)

Alternate Chemical Names

This section provides a listing of alternate names for this chemical, including trade names and synonyms.