# NIOSH Pocket Guide to Chemical Hazards
Hydrogen sulfide | CAS 7783-06-4
H2S | RTECS MX1225000
Synonyms & Trade Names Hydrosulfuric acid, Sewer gas, Sulfuretted hydrogen | DOT ID & Guide 1053 117
Exposure Limits | NIOSH REL: C 10 ppm (15 mg/m3) [10-minute]
OSHA PEL†: C 20 ppm 50 ppm [10-minute maximum peak]
IDLH 100 ppm | Conversion 1 ppm = 1.40 mg/m3
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.]
MW: 34.1 | BP: -77°F | FRZ: -122°F | Sol: 0.4%
VP: 17.6 atm | IP: 10.46 eV | RGasD: 1.19 |
Fl.P: NA (Gas) | UEL: 44.0% | LEL: 4.0% |
Flammable Gas
Incompatibilities & Reactivities Strong oxidizers, strong nitric acid, metals
Measurement Methods NIOSH 6013; OSHA ID141
Personal Protection & Sanitation Skin: Frostbite Eyes: Frostbite Wash skin: No recommendation Remove: When wet (flammable) Change: No recommendation Provide: Frostbite | 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
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
See also: INTRODUCTION