Hydrogen sulfide

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

Hydrogen sulfide

NIOSH REL

OSHA PEL

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