NIOSH logo and tagline

Hydrogen sulfide

Related Pages
Synonyms & Trade Names
Hydrosulfuric acid, Sewer gas, Sulfuretted hydrogen
CAS No.
7783-06-4
RTECS No.
MX1225000
DOT ID & Guide
1053 117
Formula
H₂S
Conversion
1 ppm = 1.40 mg/m3
IDLH
100 ppm
See: 7783064
Exposure Limits
NIOSH REL
C 10 ppm (15 mg/m3) [10-minute]
OSHA PEL
C 20 ppm 50 ppm [10-minute maximum peak] See Appendix G
Measurement Methods
NIOSH 6013;
OSHA ID141
See: NMAM or OSHA Methods
Physical Description
Colorless gas with a strong odor of rotten eggs. [Note: Sense of smell becomes rapidly fatigued & can NOT be relied upon to warn of the continuous presence of H2S. Shipped as a liquefied compressed gas.]
Molecular Weight
34.1
Boiling Point
-77°F
Freezing Point
-122°F
Solubility
0.4%
Vapor Pressure
17.6 atm
Ionization Potential
10.46 eV
Flash Point
NA (Gas)
Upper Explosive Limit
44.0%
Lower Explosive Limit
4.0%
Relative Gas Density
1.19
Flammable Gas
Incompatibilities & Reactivities
Strong oxidizers, strong nitric acid, metals
Exposure Routes
inhalation, skin and/or eye contact
Symptoms
irritation eyes, respiratory system; apnea, coma, convulsions; conjunctivitis, eye pain, lacrimation (discharge of tears), photophobia (abnormal visual intolerance to light), corneal vesiculation; dizziness, headache, lassitude (weakness, exhaustion), irritability, insomnia; gastrointestinal disturbance; liquid: frostbite
Target Organs
Eyes, respiratory system, central nervous system
Personal Protection/Sanitation
(See protection codes)
Skin:Frostbite
Eyes:Frostbite
Wash skin:No recommendation
Remove:When wet (flammable)
Change:No recommendation
Provide:Frostbite wash
First Aid
(See procedures)
Eye:Frostbite
Skin:Frostbite
Breathing:Respiratory support
Respirator Recommendations

NIOSH

Up to 100 ppm:
(APF = 25) Any powered, air-purifying 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 = 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 canister providing protection against the compound of concern
Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

See also
INTRODUCTION   ICSC CARD: 0165
Page last reviewed: October 30, 2019
Content source: National Institute for Occupational Safety and Health