NIOSH logo and tagline

Hydrogen chloride

Related Pages
Synonyms & Trade Names
Anhydrous hydrogen chloride, Aqueous hydrogen chloride, Hydrochloric acid [Note: Often used in an aqueous solution.]
CAS No.
7647-01-0
RTECS No.
MW4025000
DOT ID & Guide
1050 125(anhydrous)
1789 157(solution)
Formula
HCl
Conversion
1 ppm = 1.49 mg/m3
IDLH
50 ppm
See: 7647010
Exposure Limits
NIOSH REL
C 5 ppm (7 mg/m3)
OSHA PEL
C 5 ppm (7 mg/m3)
Measurement Methods
NIOSH 7903;
OSHA ID174SG
See: NMAM or OSHA Methods
Physical Description
Colorless to slightly yellow gas with a pungent, irritating odor. [Note: Shipped as a liquefied compressed gas.]
Molecular Weight
36.5
Boiling Point
-121°F
Freezing Point
-174°F
Solubility
(86°F): 67%
Vapor Pressure
40.5 atm
Ionization Potential
12.74 eV
Flash Point
NA
Upper Explosive Limit
NA
Lower Explosive Limit
NA
Relative Gas Density
1.27
Nonflammable Gas
Incompatibilities & Reactivities
Hydroxides, amines, alkalis, copper, brass, zinc [Note: Hydrochloric acid is highly corrosive to most metals.]
Exposure Routes
inhalation, ingestion (solution), skin and/or eye contact
Symptoms
irritation nose, throat, larynx; cough, choking; dermatitis; solution: eye, skin burns; liquid: frostbite; In Animals: laryngeal spasm; pulmonary edema
Target Organs
Eyes, skin, respiratory system
Personal Protection/Sanitation
(See protection codes)
Skin:Prevent skin contact (solution)/Frostbite
Eyes:Prevent eye contact/Frostbite
Wash skin:When contaminated (solution)
Remove:When wet or contaminated (solution)
Change:No recommendation
Provide:Eyewash (solution), Quick drench (solution), Frostbite wash
First Aid
(See procedures)
Eye:Irrigate immediately (solution)/Frostbite
Skin:Water flush immediately (solution)/Frostbite
Breathing:Respiratory support
Swallow:Medical attention immediately (solution)
Respirator Recommendations

NIOSH/OSHA

Up to 50 ppm:
(APF = 10) Any chemical cartridge respirator with cartridge(s) providing protection against the compound of concern*
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concern
(APF = 25) Any powered, air-purifying respirator with cartridge(s) providing protection against the compound of concern*
(APF = 10) Any supplied-air respirator*
(APF = 50) Any self-contained breathing apparatus with a full facepiece

Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) 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 positive-pressure breathing apparatus

Escape:
(APF = 50) 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

Important additional information about respirator selection

See also
INTRODUCTION   ICSC CARD: 0163   MEDICAL TESTS: 0116
Page last reviewed: October 30, 2019
Content source: National Institute for Occupational Safety and Health