Substance profile
Hydrogen Sulfide
Hydrogen Sulfide is a colorless gas [Shipped as a liquefied compressed gas] with strong odor of rotten eggs.
01 · Identification
What Hydrogen Sulfide is
Hydrogen Sulfide is a colorless gas [Shipped as a liquefied compressed gas] with strong odor of rotten eggs. Its molecular formula is H2S and its molecular weight is 34.08 g/mol. It boils at -60.3 °C, melts at -85.5 °C.
Under the GHS it carries the signal word Danger. It is classed as flammable agents - 4th degree.
02 · Identifiers
Hydrogen Sulfide identifiers and molecular data
Hydrogen Sulfide CAS number and EC number
Hydrogen Sulfide molecular formula and molecular weight
Other names for Hydrogen Sulfide
- hydrogen sulphide, hydrogen sulfide
03 · GHS classification
Hydrogen Sulfide hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Hydrogen Sulfide pictograms and signal word
Hydrogen Sulfide hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Flammable gases GHS chapter 2.2 | Category 1A | H220 | GHS02 |
| Acute toxicity - inhalation GHS chapter 3.1 | Category 1 or 2 | H330 | GHS06 |
| Hazardous to the aquatic environment - acute GHS chapter 4.1 | Category 1 | H400 | GHS09 |
Where two values are shown with “or”, the hazard statement is shared by more than one category or by more than one class, and the code alone does not say which. H272, for example, belongs to oxidising liquids and to oxidising solids — the physical state decides. The binding answer for a specific entry is in the CLP Annex VI table itself.
Hydrogen Sulfide hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H220 | Extremely flammable gas. |
| H330 | Fatal if inhaled. |
| H400 | Very toxic to aquatic life. |
This page lists only the codes assigned to Hydrogen Sulfide. The full reference lives on the hazard statements hub, the precautionary statements hub and the GHS pictograms hub.
Safety Data Sheet
Getting an SDS for Hydrogen Sulfide
A Safety Data Sheet is written for a product, not for a substance: the supplier of the grade you actually buy issues it, so two suppliers of Hydrogen Sulfide issue two different sheets. That is why there is no single authoritative SDS for a substance to download — what there is, is the job of collecting the sheets for the products you hold and keeping them current as suppliers revise them.
04 · Precautionary statements
Hydrogen Sulfide precautionary statements
CLP Annex VI assigns 10 precautionary statements to Hydrogen Sulfide. They are grouped the way a label groups them: what to do before handling, what to do when something has already happened, how to store it and how to dispose of it.
Prevention
What to do before and during handling so the hazard never happens.
Response
What to do once exposure, spillage or fire has already happened.
Disposal
What has to happen to the contents and the empty container.
Reading the notation. … is a blank the supplier fills in — not a truncated sentence.· [square brackets] mark a part printed only when it applies.
05 · Names in the regulation
Hydrogen Sulfide name in 23 EU languages
CLP Annex VI Part 3 is published in every language edition of the regulation, and the identification column is written out in each of them. Nothing below is translated by us: each line is the name as that edition prints it. Under Art. 18(2) the substance name from Annex VI is a lawful product identifier, so this is the wording to put on a label going to that market — and where the cell lists several designations, any one of them qualifies.
| Language | Name in CLP Annex VI Part 3 |
|---|---|
| Bulgarian български | сероводород, водороден сулфид |
| Spanish español | Sulfuro de hidrógeno |
| Czech čeština | sirovodík sulfan |
| Danish dansk | hydrogensulfid |
| German Deutsch | Schwefelwasserstoff |
| Estonian eesti | vesiniksulfiid |
| Greek ελληνικά | υδρόθειο |
| English English | hydrogen sulphide, hydrogen sulfide |
| French français | sulfure d’hydrogène, hydrogène sulfuré |
| Croatian hrvatski | sumporovodik, vodikov sulfid |
| Italian italiano | acido solfidrico, solfuro di idrogeno |
| Latvian latviešu | sērūdeņradis |
| Lithuanian lietuvių | vandenilio sulfidas |
| Hungarian magyar | hidrogén-szulfid kén-hidrogén |
| Maltese Malti | sulfur tal-idroġenu, sulfur tal-idroġenu |
| Dutch Nederlands | waterstofsulfide |
| Polish polski | siarkowodór |
| Portuguese português | sulfureto de hidrogénio |
| Romanian română | hidrogen sulfurat |
| Slovak slovenčina | sírovodík, sulfán |
| Slovenian slovenščina | vodikov sulfid, vodikov sulfid |
| Finnish suomi | rikkivety, vetysulfidi |
| Swedish svenska | svavelväte, vätesulfid |
All 23 language editions of Annex VI carry this entry. Irish is the twenty-fourth official EU language and has no line here for a different reason: no consolidated CLP text has ever been published in Irish, so there is no Irish edition of Annex VI to quote a name from. Source: consolidated CLP, CELEX 02008R1272, language editions. © European Union, https://eur-lex.europa.eu — only the electronic Official Journal of the European Union is authentic.
06 · Label elements
Hydrogen Sulfide GHS label elements
Everything CLP Annex VI fixes for Hydrogen Sulfide, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Hydrogen Sulfide
- Extremely flammable gas.
- Fatal if inhaled.
- Very toxic to aquatic life.
- Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
- Keep container tightly closed.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Use only outdoors or in a well-ventilated area.
- Avoid release to the environment.
- IF INHALED:
- Immediately call a POISON CENTER/doctor/…
- Collect spillage.
- Store in a well-ventilated place.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Hydrogen Sulfide in the GHS label constructor →
07 · Health hazards
Hydrogen Sulfide health hazards and exposure limits
Hydrogen Sulfide hazard 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. People can smell it at low levels.
Source: Agency for Toxic Substances and Disease Registry (ATSDR)
Hydrogen Sulfide carcinogenicity classification
There are no published reports of carcinogenesis, mutagenesis, or teratogenesis attributable to hydrogen sulfide exposure.
Source: Hazardous Substances Data Bank (HSDB)
An IARC group and a CLP classification answer different questions. IARC judges whether the evidence for cancer in humans is strong enough; CLP Annex VI is the legally binding EU classification. A substance can carry one and not the other.
Hydrogen Sulfide occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 20 ppm (C), 50 ppm (Peak) [10 min, once only, if no other measurable exposure occurs] | Occupational Safety and Health Administration (OSHA) |
| PEL | C 20 ppm 50 ppm [10-minute maximum peak] See Appendix G | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 10 ppm (15 mg/m³) [10 min] | Occupational Safety and Health Administration (OSHA) |
| REL | C 10 ppm (15 mg/m3) [10-minute] | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 100 ppm (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 100.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | 100 ppm | Hazardous Substances Data Bank (HSDB) |
These are United States values. The European Union sets its own indicative and binding limits, and the figure that applies at a given workplace is the one in the local regulation — not the one shown here.
08 · Physical and chemical properties
Hydrogen Sulfide properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
Hydrogen Sulfide boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | -60.33 °C (-76.6 °F) | HSDB | |
| -60.56 °C (-77 °F) | NIOSH | ||
| -60.33 °C (-76.6 °F) | at 760 mmHg | CAMEO |
Hydrogen Sulfide melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -85.49 °C (-121.9 °F) | HSDB | |
| -85.56 °C (-122 °F) | NIOSH | ||
| -85.5 °C (-121.9 °F) | CAMEO |
Hydrogen Sulfide density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.92 g/cm³ | ICSC | |
| 0.916 g/cm³ | at 24.44 °C | OSHA | |
| 1.393 g/cm³ | at 25 °C | DOE PAC |
Hydrogen Sulfide solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Soluble in glycerol, gasoline, kerosene, carbon disulfide, crude oil. | HSDB | |
| 1 g dissolves in 94.3 ml absolute alcohol at 20 °C; 1 g dissolves in 48.5 mL ether at 20 °C | at 20 °C | HSDB | |
| In water, 3980 mg/L at 20 °C | at 20 °C | HSDB |
Hydrogen Sulfide vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 13380 mmHg | NIOSH | |
| 13600 mmHg | at 20 °C | HSDB | |
| 15600 mmHg | at 25 °C | HSDB |
Hydrogen Sulfide flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | 260 °C (500 °F) | Haz-Map | |
| NA (Gas) | NIOSH | ||
| Flammable gas | ICSC |
Hydrogen Sulfide autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 260 °C (500 °F) | HSDB | |
| 270 °C (518 °F) | ICSC |
Hydrogen Sulfide lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 4 % by volume | HSDB | |
| 4.3 % by volume | HSDB |
Hydrogen Sulfide upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 44 % by volume | HSDB | |
| 46 % by volume | HSDB |
Hydrogen Sulfide vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 1.189 (air = 1) | HSDB | |
| 1.19 (air = 1) | CAMEO |
Hydrogen Sulfide odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | 0.05 ppm | HSDB | |
| Detection limit in air: 1.30x10-1 ppm (purity not specified) | HSDB | ||
| Detection limit in air: 1.80x10-4 ppm (purity not specified) | HSDB |
Hydrogen Sulfide critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 100.4 °C (212.7 °F) | HSDB | |
| 99.95 °C (211.9 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Hydrogen Sulfide fire and explosion behaviour
These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.
Hydrogen Sulfide fire potential
FLAMMABLE GAS. LOW IGNITION ENERGY.
Source: Hazardous Substances Data Bank (HSDB)
Corrosivity
Anhydrous hydrogen sulfide has low general corrosivity toward carbon steel, aluminum, Inconel, Stellite and 300-series stainless steels at moderate temperatures. Temperatures greater than ca 260 °C can produce severe sulfidation of carbon steel. Wet hydrogen sulfide can be quite corrosive to carbon steel.
Source: HSDB
10 · Handling and storage
Hydrogen Sulfide storage and handling
Hydrogen Sulfide safe 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.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Hydrogen Sulfide storage conditions
Store in a cool, dry, well-ventilated location. Separate from oxidizable materials.
Source: Hazardous Substances Data Bank (HSDB)
Hydrogen Sulfide incompatible materials
Fuming nitric acid reacts with incandescence with hydrogen sulfide.
Source: Hazardous Substances Data Bank (HSDB)
Planning storage for a mix of chemicals? Check Hydrogen Sulfide in the storage compatibility matrix →
11 · Transport
Hydrogen Sulfide UN number and transport classification
Transport classification is a separate system from the GHS classification above. It decides how a package is marked and how a load may be carried; it does not follow from the workplace label, and the workplace label does not follow from it. The entries below are linked by CAS number, never by name.
Hydrogen Sulfide under UN 1053 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| HYDROGEN SULPHIDE | 2 | 2TF | — | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 2 is “Gases” (ADR 2.1.1.1).
United States · 49 CFR 172.101 Hazardous Materials Table
| Proper shipping name (column 2) | Class or division | PG | Labels (column 6) |
|---|---|---|---|
| Hydrogen sulfide | 2.3 | — | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 2.3 is “Poisonous gas” (49 CFR 173.2).
12 · Questions
Hydrogen Sulfide — frequently asked questions
What is the CAS number of Hydrogen Sulfide?
The CAS number of Hydrogen Sulfide is 7783-06-4. Its EC number is 231-977-3.
What is the chemical formula of Hydrogen Sulfide?
The molecular formula of Hydrogen Sulfide is H2S and its molecular weight is 34.08 g/mol.
What does a Hydrogen Sulfide label have to show?
Under CLP Annex VI the label for Hydrogen Sulfide carries the pictograms Flame, Skull and crossbones and Environment and the signal word is Danger.
Is Hydrogen Sulfide flammable?
Yes. CLP Annex VI assigns Hydrogen Sulfide H220 — extremely flammable gas. The flash point reported for it is 260 °C (500 °F) (Haz-Map).
Is Hydrogen Sulfide a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Hydrogen Sulfide. Annex VI is a list of agreed classifications, not a list of substances found safe, so this is an absence of a classification rather than a clean bill of health.
What is the exposure limit for Hydrogen Sulfide?
The US occupational exposure limit reported for Hydrogen Sulfide is 20 ppm (C), 50 ppm (Peak) [10 min, once only, if no other measurable exposure occurs] (Occupational Safety and Health Administration (OSHA)). Limits differ by country: the EU sets its own indicative and binding values, and the figure that applies at a given workplace is the one in the local regulation.
What is the boiling point of Hydrogen Sulfide?
The boiling point reported for Hydrogen Sulfide is -60.33 °C (-76.6 °F) (HSDB).
What is the melting point of Hydrogen Sulfide?
The melting point reported for Hydrogen Sulfide is -85.49 °C (-121.9 °F) (HSDB).
How should Hydrogen Sulfide be stored?
CLP Annex VI assigns Hydrogen Sulfide the storage statement P403. Store in a cool, dry, well-ventilated location. Separate from oxidizable materials. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Hydrogen Sulfide
Keep going: substances starting with H, or search the whole database by name, CAS number, pictogram or signal word.