Hydrogen Sulfide

1Identification

Name

Hydrogen Sulfide

IUPAC name

sulfane

CAS number

7783-06-4

EC number

231-722-6

Molecular formula

H2S

Molecular weight

34.08 g/mol

InChIKey

RWSOTUBLDIXVET-UHFFFAOYSA-N

SMILES

S

PubChem CID

402

Synonyms

hydrogen sulfide, Hydrosulfuric acid, Dihydrogen sulfide, Dihydrogen monosulfide, Stink DAMP, Hydrogen sulphide, Sulfureted hydrogen, Sewer gas, Hydrogene sulfure, Acide sulfhydrique, Schwefelwasserstoff, Zwavelwaterstof, Siarkowodor, Hydrogen-sulfide

Recommended uses

• Hydrogen sulfide is produced naturally by decaying organic matter and is released from sewage sludge, liquid manure, sulfur hot springs, and natural gas. It is a byproduct of many industrial processes including petroleum refining, tanning, mining, wood pulp processing, rayon manufacturing, sugar beet processing, and hot asphalt paving. Hydrogen sulfide is used to produce elemental sulfur, sulfuric acid, and heavy water for nuclear reactors. [ATSDR Medical Management]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Steel Producing [Category: Industry] Petroleum Production and Refining [Category: Industry] Pulp and Paper Processing [Category: Industry] Textiles (Fiber & Fabric Manufacturing) [Category: Industry] Mining [Category: Industry] Sewer and Wastewater Treatment [Category: Industry] Leather Tanning and Processing [Category: Industry] Farming (Respiratory Hazards) [Category: Industry]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Smoking cigarettes [Category: Food & Drugs]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases

Use categories: Chemical Classes -> Inorganic substances

Description

• Hydrogen sulfide (H2S) occurs naturally in crude petroleum, natural gas, volcanic gases, and hot springs. It can also result from bacterial breakdown of organic matter. It is also produced by human and animal wastes. Bacteria found in your mouth and gastrointestinal tract produce hydrogen sulfide from bacteria decomposing materials that contain vegetable or animal proteins. Hydrogen sulfide can also result from industrial activities, such as food processing, coke ovens, kraft paper mills, tanneries, and petroleum refineries. Hydrogen sulfide is a flammable, colorless gas with a characteristic odor of rotten eggs. It is commonly known as hydrosulfuric acid, sewer gas, and stink damp.
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Hydrogen sulfide appears as a colorless gas having a strong odor of rotten eggs. Boiling point -60.2 °C. Shipped as a liquid confined under its own vapor pressure. Density (liquid) 8.3 lb / gal. Contact with the unconfined liquid can cause frostbite by evaporative cooling. Gas is very toxic by inhalation. Fatigues the sense of smell which cannot be counted on to warn of the continued presence of the gas. Prolonged exposure of closed containers to heat may result in their violent rupturing and rocketing. Rate of onset: Immediate & Delayed Persistence: Minutes to hours Odor threshold: 0.1 ppm Source/use/other hazard: Disinfectant lubricant/oils; interm for HC manufacture;
  CAMEO Chemicals
• Sulfur atom is a nonmetal atom and a chalcogen. It has a role as a macronutrient.
  ChEBI

2Hazard identification

Signal word

Danger

Pictograms

GHS02, GHS06, GHS09

Classification source

Regulation (EC) No 1272/2008 of the European Parliament and of the Council

Precautionary statements

Other reported classifications

5 classification records exist across sources. Differences usually reflect purity, physical form or impurities.

NFPA 704 rating

• 4 - Materials that, under emergency conditions, can be lethal.
  Hazardous Substances Data Bank (HSDB)
• 4 - Materials that rapidly or completely vaporize at atmospheric pressure and normal ambient temperature or that are readily dispersed in air and burn readily.
  Hazardous Substances Data Bank (HSDB)
• 0 - Materials that in themselves are normally stable, even under fire conditions.
  Hazardous Substances Data Bank (HSDB)

Health hazards

• Exposure to very high concentrations causes immediate death. Also death or permanent injury may occur after very short exposure to small quantities. It acts directly upon the nervous system resulting in paralysis of respiratory centers. (EPA, 1998)
  CAMEO Chemicals
• · Fire may produce irritating and/or toxic gases. · Contact may cause burns to skin and eyes. · Contact with molten substance may cause severe burns to skin and eyes. · Runoff from fire control or dilution water may cause environmental contamination.
  Emergency Response Guidebook (ERG)
• · TOXIC; may be fatal if inhaled, ingested or absorbed through skin. · Inhalation or contact with some of these materials will irritate or burn skin and eyes. · Methyl chloroacetate (UN2295) is an eye irritant/lachrymator (causes flow of tears). · Fire will produce irritating, corrosive and/or toxic gases. · Vapors may cause dizziness or asphyxiation, especially when in closed or confined areas. · Runoff from fire control or dilution water may cause environmental contamination.
  Emergency Response Guidebook (ERG)

Fire hazards

• Compound is heavier than air and may travel a considerable distance to source of ignition and flash back. It forms explosive mixtures with air over a wide range. Also reacts explosively with bromine pentafluoride, chlorine trifluoride, nitrogen triiodide, nitrogen trichloride, oxygen difluoride, and phenyl diazonium chloride. When heated to decomposition, it emits highly toxic fumes of oxides of sulfur. Incompatible with many materials including strong oxidizers, metals, strong nitric acid, bromine pentafluoride, chlorine trifluoride, nitrogen triiodide, nitrogen trichloride, oxygen difluoride and phenyl diazonium chloride. Avoid physical damage to containers; sources of ignition;
  CAMEO Chemicals
• · Flammable/combustible material. · May be ignited by friction, heat, sparks or flames. · Some may burn rapidly with flare-burning effect. · Powders, dusts, shavings, borings, turnings or cuttings may explode or burn with explosive violence. · Substance may be transported in a molten form at a temperature that may be above its flash point. · May re-ignite after fire is extinguished.
  Emergency Response Guidebook (ERG)
• · HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. CAUTION: Methanol (UN1230) will burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.) · Vapors may form explosive mixtures with air. · Vapors may travel to source of ignition and flash back. · Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas (sewers, basements, tanks, etc.). · Vapor explosion and poison hazard indoors, outdoors or in sewers. · Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. · Runoff to sewer may create fire or explosion hazard.
  Emergency Response Guidebook (ERG)

Hazards summary

• Hydrogen sulfide (H2S) occurs naturally in crude petroleum, natural gas, volcanic gases, and hot springs. It can also result from bacterial breakdown of organic matter. It is also produced by human and animal wastes. Bacteria found in your mouth and gastrointestinal tract produce hydrogen sulfide from bacteria decomposing materials that contain vegetable or animal proteins. Hydrogen sulfide can also result from industrial activities, such as food processing, coke ovens, kraft paper mills, tanneries, and petroleum refineries. Hydrogen sulfide is a flammable, colorless gas with a characteristic odor of rotten eggs. It is commonly known as hydrosulfuric acid, sewer gas, and stink damp.
  Agency for Toxic Substances and Disease Registry (ATSDR)
• CNS injury is immediate and significant after exposure to hydrogen sulfide. At high concentrations, only a few breaths can lead to immediate loss of consciousness, coma, respiratory paralysis, seizures, and death. . . . Hydrogen sulfide is a mucous membrane and respiratory tract irritant; pulmonary edema, which may be immediate or delayed, can occur after exposure to high concentrations. [ATSDR Medical Management] Like cyanide, causes cellular asphyxiation; Also a mucous membrane irritant; IDLH = 100 ppm; Pulmonary edema at 300-500 ppm; Rapidly fatal at 600-800 ppm; [Olson, p. 271] H2S is heavier than air; it displaces air in confined spaces.
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases

3Composition / information on ingredients

This page describes the pure substance. Commercial products may be solutions or mixtures. Check Section 3 of your supplier's SDS for concentrations and other ingredients.

4First-aid measures

• Warning: Caution is advised. Vital signs should be monitored closely. Signs and Symptoms of Acute Hydrogen Sulfide Exposure: Signs and symptoms of acute exposure to hydrogen sulfide may include tachycardia (rapid heart rate) or bradycardia (slow heart rate), hypotension (low blood pressure), cyanosis (blue tint to skin and mucous membrane), cardiac palpitations, and cardiac arrhythmias. Dyspnea (shortness of breath), tachypnea (rapid respiratory rate), bronchitis, pulmonary edema, respiratory depression, and respiratory paralysis may occur. Neurological effects include giddiness, irritability, drowsiness, weakness, confusion, delirium, amnesia, headache, sweating, and dizziness.
  CAMEO Chemicals
• General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).
  Emergency Response Guidebook (ERG)
• (General first aid procedures) Eye: Frostbite - If eye tissue is frozen, seek medical attention immediately; if tissue is not frozen, immediately and thoroughly flush the eyes with large amounts of water for at least 15 minutes, occasionally lifting the lower and upper eyelids. If irritation, pain, swelling, lacrimation, or photophobia persist, get medical attention as soon as possible. Skin: 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. Breathing: Respiratory support
  The National Institute for Occupational Safety and Health (NIOSH)

Symptoms of exposure

• Cough. Headache. Dizziness. Nausea. Laboured breathing. Shortness of breath. Irregular heartbeat. Convulsions. Unconsciousness.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• ON CONTACT WITH LIQUID: FROSTBITE.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Redness. Pain.
  ILO-WHO International Chemical Safety Cards (ICSCs)

5Fire-fighting measures

• Stop flow of gas before extinguishing fire. Use water spray, dry chemical, or carbon dioxide. Use water sprat to keep fire-exposed containers cool.
  Hazardous Substances Data Bank (HSDB)
• STOP FLOW OF GAS. USE WATER TO KEEP FIRE EXPOSED CONTAINERS COOL & TO PROTECT MEN EFFECTING SHUT OFF.
  Hazardous Substances Data Bank (HSDB)
• If material is on fire or involved in fire: Do not extinguish fire unless flow can be stopped. Use water in flooding quantities as fog. Apply water from as far a distance as possible. Cool all affected containers with flooding quantities of water. Use water spray to knock-down vapors.
  Hazardous Substances Data Bank (HSDB)

6Accidental release measures

Isolation and evacuation

• Excerpt from ERG Guide 117 [Gases - Toxic - Flammable (Extreme Hazard)]: IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 100 meters (330 feet) in all directions. SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 1053 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)
  CAMEO Chemicals
• Immediate precautionary measure · Isolate spill or leak area for at least 25 meters (75 feet) in all directions. Large Spill · Consider initial downwind evacuation for at least 100 meters (330 feet). Fire · If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.
  Emergency Response Guidebook (ERG)

Spill cleanup

• Remove all ignition sources. Evacuate danger area! Consult an expert! Personal protection: gas-tight chemical protection suit including self-contained breathing apparatus. Do NOT let this chemical enter the environment. Shut off cylinder if possible. Ventilation. Remove gas with fine water spray. Isolate the area until the gas has dispersed.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Eliminate all ignition sources. Approach release from upwind. Stop or control the leak, if this can be done without undue risk. Use water spray to cool and disperse vapors, protect personnel, and dilute spills to form nonflammable mixtures. Control runoff and isolate discharge material for proper disposal.
  Hazardous Substances Data Bank (HSDB)
• 1) REMOVE ALL IGNITION SOURCES. 2) VENTILATE AREA OF SPILL OR LEAK TO DISPERSE GAS. 3) IF IN GASEOUS FORM, STOP FLOW OF GAS. IF SOURCE OF LEAK IS CYLINDER & ... CANNOT BE STOPPED IN PLACE, REMOVE THE LEAKING CYLINDER TO A SAFE PLACE IN THE OPEN AIR, & REPAIR THE LEAK OR ALLOW THE CYCLINDER TO EMPTY. 4) IF IN LIQ FORM, ALLOW TO VAPORIZE.
  Hazardous Substances Data Bank (HSDB)
• METHODS FOR THE BIOLOGICAL TREATMENT OF ACID MINE DRAINAGE WERE EVALUATED. HYDROGEN SULFIDE PRODUCED BY SULFATE REDUCTION CAN POTENTIALLY REACT WITH METALS IN SOLUTION TO FORM METAL SULFIDE PRECIPITATES. THE UTILITY OF A PILOT PLANT DESIGN INCORPORATING ANAEROBIC DIGESTION, SULFATE REDUCTION, AERATION AND FINAL CLARIFICATION AND SETTLING WAS DEMONSTRATED.
  Hazardous Substances Data Bank (HSDB)

7Handling and storage

• Fireproof. Separated from strong oxidants. Cool. Keep in a well-ventilated room. Install continous monitoring system with alarm. Provision to contain effluent from fire extinguishing. Store in an area without drain or sewer access.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Store in a cool, dry, well-ventilated location. Separate from oxidizable materials.
  Hazardous Substances Data Bank (HSDB)

8Exposure controls / personal protection

Personal protective equipment

• Excerpt from NIOSH Pocket Guide for Hydrogen sulfide: Skin: 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: FROSTBITE - Wear appropriate eye protection to prevent eye contact with the liquid that could result in burns or tissue damage from frostbite. Wash skin: No recommendation is made specifying the need for washing the substance from the skin (either immediately or at the end of the work shift).
  CAMEO Chemicals
• Wear special protective clothing and positive pressure self-contained breathing apparatus.
  Hazardous Substances Data Bank (HSDB)
• /WEAR/ RUBBER-FRAMED GOGGLES; APPROVED RESP PROTECTION.
  Hazardous Substances Data Bank (HSDB)
• THE USE OF LIQUID MANURE STORAGE FACILITIES POSES SEVERAL SERIOUS THREATS: TOXIC GAS INHALATION, ASPHYXIATION, ASPIRATION OF LIQUID MANURE, AND INFECTION. HYDROGEN SULFIDE POISONING IN A MANURE STORAGE PIT RESULTED IN THREE DEATHS. THESE ACCIDENTS CAN BE PREVENTED BY THE USE OF A SELF-CONTAINED BREATHING APPARATUS AND A SAFETY LINE, AS WELL AS THE PRESENCE OF A SECOND PERSON FOR RESCUE IF NECESSARY.
  Hazardous Substances Data Bank (HSDB)

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…
  The National Institute for Occupational Safety and Health (NIOSH)

9Physical and chemical properties

10Stability and reactivity

Reactivity

• HYDROGEN SULFIDE reacts as an acid and as a reducing agent. Explodes on contact with oxygen difluoride, bromine pentafluoride, chlorine trifluoride, dichlorine oxide, silver fulminate. May ignite and explode when exposed to powdered copper in oxygen [Mertz, V. et al., Ber., 1880, 13, p. 722]. May react similarly with other powdered metals. Ignites on contact with metal oxides and peroxides (barium peroxide, chromium trioxide, copper oxide, lead dioxide, manganese dioxide, nickel oxide, silver oxide, silver dioxide, thallium trioxide, sodium peroxide, mercury oxide, calcium oxide) [Mellor, 1947, vol. 10, p. 129, 141].
  CAMEO Chemicals
• Highly flammable; a flame can very easily flash back to the source of leak.
  CAMEO Chemicals

Incompatible materials and hazardous reactions

• Fuming nitric acid reacts with incandescence with hydrogen sulfide.
  Hazardous Substances Data Bank (HSDB)
• Forms explosive reactions with bromine pentafluoride, chlorine trifluoride, nitrogen triiodide, nitrogen trichloride, oxygen difluoride and phenyl diazonium chloride.
  Hazardous Substances Data Bank (HSDB)
• Addition of powdered copper to 1:2 mixture of hydrogen sulfide and oxygen causes the metal to become incandescent and ignite the explosive mixture.
  Hazardous Substances Data Bank (HSDB)

Chemical stability

• Water solns of H2S are not stable, absorbed oxygen causes the formation of elemental sulfur, and the solns become turbid rapidly.
  Hazardous Substances Data Bank (HSDB)

11Toxicological information

Target organs

• Neurological (Nervous System), Respiratory (From the Nose to the Lungs)
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Nervous Respiratory
  EPA Integrated Risk Information System (IRIS)

Short-term exposure effects

• Rapid evaporation of the liquid may cause frostbite. The substance is irritating to the eyes and respiratory tract. Inhalation of this gas may cause lung oedema. The effects may be delayed. Medical observation is indicated. The substance may cause effects on the central nervous system. Exposure could cause unconsciousness. Exposure could cause death.
  ILO-WHO International Chemical Safety Cards (ICSCs)

12Ecological information

Not available in the public sources we compile. Check Section 12 of the supplier's SDS.

13Disposal considerations

• Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U135, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.
  Hazardous Substances Data Bank (HSDB)
• SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal.
  Hazardous Substances Data Bank (HSDB)
• A potential candidate for rotary kiln incineration at a temperature range of 820 to 1,600 °C and residence times of seconds for liquids and gases, and hours for solids.
  Hazardous Substances Data Bank (HSDB)

14Transport information

UN number: UN 1053

Shipping name

• UN 1053; Hydrogen sulfide
  Hazardous Substances Data Bank (HSDB)
• IMO 2.3; Hydrogen sulfide
  Hazardous Substances Data Bank (HSDB)

DOT hazard class

• Hydrogen sulfide
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• UN1053
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• Div 2.3 Poisonous gas (49 eCFR § 173.115)
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172

DOT label

• Poison Gas Flammable Gas
  CAMEO Chemicals

UN classification

• UN Hazard Class: 2.3; UN Subsidiary Risks: 2.1
  ILO-WHO International Chemical Safety Cards (ICSCs)

Emergency Response Guidebook

• 2448 133
  Emergency Response Guidebook (ERG)
• 1228 131
  Emergency Response Guidebook (ERG)

How DOT hazard classes work →

15Regulatory information

• Hydrogen sulfide is designated as a hazardous substance under section 311(b)(2)(A) of the Federal Water Pollution Control Act and further regulated by the Clean Water Act Amendments of 1977 and 1978. These regulations apply to discharges of this substance. This designation includes any isomers and hydrates, as well as any solutions and mixtures containing this substance.
  Hazardous Substances Data Bank (HSDB)
• Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 100 lb or 45.4 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b).
  Hazardous Substances Data Bank (HSDB)
• U135; As stipulated in 40 CFR 261.33, when hydrogen sulfide, as a commercial chemical product or manufacturing chemical intermediate or an off-specification commercial chemical product or a manufacturing chemical intermediate, becomes a waste, it must be managed according to Federal and/or State hazardous waste regulations. Also defined as a hazardous waste is any residue, contaminated soil, water, or other debris resulting from the cleanup of a spill, into water or on dry land, of this waste. Generators of small quantities of this waste may qualify for partial exclusion from hazardous waste regulations (40 CFR 261.5).
  Hazardous Substances Data Bank (HSDB)

Overview of SDS regulations (OSHA HazCom, WHMIS, REACH/CLP) →

16Other information

Compiled from PubChem CID 402 and the sources it aggregates (attributed inline). Data retrieved 2026-10-12. This summary describes the pure substance and is not a supplier SDS.