Substance profile
Phosphine
Phosphine is a colorless gas; flammable with a disagreeable, garlic-like odor.
01 · Identification
What Phosphine is
Phosphine is a colorless gas; flammable with a disagreeable, garlic-like odor. It boils at -87.7 °C, melts at -134 °C, is slightly soluble in water.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
02 · Identifiers
Phosphine identifiers and molecular data
Phosphine CAS number and EC number
Phosphine molecular formula and molecular weight
03 · GHS classification
Phosphine hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Phosphine pictograms and signal word
Phosphine 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 |
| Skin corrosion/irritation GHS chapter 3.2 | Category 1A or 1B or 1C | H314 | GHS05 |
| 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.
Phosphine hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H220 | Extremely flammable gas. |
| H330 | Fatal if inhaled. |
| H314 | Causes severe skin burns and eye damage. |
| H400 | Very toxic to aquatic life. |
This page lists only the codes assigned to Phosphine. 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 Phosphine
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 Phosphine 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
Phosphine precautionary statements
CLP Annex VI assigns 13 precautionary statements to Phosphine. 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
Phosphine 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 | фосфин |
| Spanish español | Fosfina |
| Czech čeština | fosfin |
| Danish dansk | fosfin |
| German Deutsch | Phosphin |
| Estonian eesti | Fosfiin |
| Greek ελληνικά | φωσφίνη |
| English English | phosphine |
| French français | phosphine |
| Croatian hrvatski | fosfin |
| Italian italiano | fosfina |
| Latvian latviešu | Fosfīns |
| Lithuanian lietuvių | fosfinas |
| Hungarian magyar | foszfin |
| Maltese Malti | fosfina |
| Dutch Nederlands | fosfine |
| Polish polski | fosfan, fosfina |
| Portuguese português | fosfina |
| Romanian română | fosfină |
| Slovak slovenčina | fosfán |
| Slovenian slovenščina | fosfin |
| Finnish suomi | fosfiini |
| Swedish svenska | fosfin |
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
Phosphine GHS label elements
Everything CLP Annex VI fixes for Phosphine, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Phosphine
- Extremely flammable gas.
- Fatal if inhaled.
- Causes severe skin burns and eye damage.
- 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.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF SWALLOWED:
- IF INHALED:
- Immediately call a POISON CENTER/doctor/…
- Do NOT induce vomiting.
- 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 Phosphine in the GHS label constructor →
07 · Health hazards
Phosphine health hazards and exposure limits
Phosphine hazard summary
Phosphine is a colorless, flammable, and explosive gas at ambient temperature that has the odor of garlic or decaying fish. Small amounts occur naturally from the break down of organic matter. It is slightly soluble in water. Phosphine is used in semiconductor and plastics industries, in the production of a flame retardant, and as a pesticide in stored grain.
Source: Agency for Toxic Substances and Disease Registry (ATSDR)
Phosphine carcinogenicity classification
CLASSIFICATION: D; not classifiable as to human carcinogenicity. BASIS FOR CLASSIFICATION: Based on inadequate data in animals and no tumor data in humans. While phospine has not been associated with cancer in humans, there is some evidence of chromosomal damage (transient chromatid deletions, gaps and breaks, persistent chromosomal translocations). A relationship between these genetic effects and the development of cancer in humans is sometimes postulated. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: Inadequate.
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.
Phosphine occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 0.3 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 0.3 ppm (0.4 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| PEL | TWA 0.3 ppm (0.4 mg/m3) See Appendix G | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 0.3 ppm (0.4 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | 1 ppm (1 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | TWA 0.3 ppm (0.4 mg/m3) ST 1 ppm (1 mg/m3) | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 50 ppm (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 50.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | 50 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
Phosphine 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.
Phosphine boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | -87.75 °C (-125.9 °F) | HSDB | |
| -87.78 °C (-126 °F) | NIOSH | ||
| -87.78 °C (-126 °F) | at 760 mmHg | CAMEO |
Phosphine melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -133.8 °C (-208.8 °F) | HSDB | |
| -133.89 °C (-209 °F) | NIOSH | ||
| -132.78 °C (-207 °F) | CAMEO |
Phosphine density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.0015 g/cm³ | ICSC | |
| 0.8 g/cm³ | ICSC | ||
| 0.0014 g/cm³ | at 25 °C | HSDB |
Phosphine solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Insoluble in water | HSDB | |
| Slightly soluble in cold water. Insoluble in hot water. | HSDB | ||
| Slightly soluble in water (0.26 volume at 20 °C) | at 20 °C | HSDB |
Phosphine vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 31390 mmHg | NIOSH | |
| 26160 mmHg | at 20 °C | ICSC | |
| 29300 mmHg | at 25 °C | HSDB |
Phosphine flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | NA (Gas) | NIOSH | |
| Flammable gas | ICSC |
Phosphine autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 100 °C (212 °F) | HSDB | |
| 38 °C (100.4 °F) | ICSC |
Phosphine lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 1.79 % by volume | NIOSH | |
| 1.6 % by volume | estimated | ICSC |
Phosphine upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 100 % by volume | estimated | ICSC |
| Dangerous fire hazard from spontaneous chemical reaction. (EPA, 1998) | CAMEO | ||
| Dangerous fire hazard from spontaneous chemical reaction. | OSHA |
Phosphine vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 1.17 (air = 1) | HSDB | |
| 1.18 (air = 1) | ICSC |
Phosphine odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | 0.03 PPM | HSDB | |
| Air: 0.51 uL/L; Water: 0.0002 mg/L; Odor Safety Class: D; D= 10-50% of attentive persons can detect TLV concn in the air. | HSDB | ||
| Phosphine's characteristic decayed fish odor is barely detectable at concentrations of 1.5 to 3 ppm. | HSDB |
Phosphine critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 51.35 °C (124.4 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Phosphine 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.
Phosphine fire potential
Very dangerous fire hazard by spontaneous chemical reaction.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Phosphine storage and handling
Phosphine safe storage
Fireproof. Keep in a well-ventilated room.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Phosphine storage conditions
Keep container tightly closed in a dry and well-ventilated place. Contents under pressure. Storage class (TRGS 510): Gases.
Source: Hazardous Substances Data Bank (HSDB)
Phosphine incompatible materials
Incompatible materials: Strong oxidizing agents, oxidizing agents, halogens, nitric acid.
Source: Hazardous Substances Data Bank (HSDB)
Phosphine reactivity
PHOSPHINE is a reducing agent. Ignites spontaneously in air when pure [Sidgwick, 1950, p. 729]. Liquefied phosphine can be detonated [Rust, 1948, p. 301]. Ignites or reacts violently with boron trichloride, dichlorine oxide, halogens (bromine, chlorine, iodine), metal nitrates, nitrogen oxides, nitric acid, nitrous acid, nitrogen trichloride [Bretherick, 5th ed., 1995, p. 1562]. Forms explosive mixtures with even small amounts of oxygen. Autoignites at low pressures [Fisher, E. O. et al., Angew. Chem., 1968, 7, p. 136].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Phosphine in the storage compatibility matrix →
11 · Transport
Phosphine 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.
The same CAS number is shipped under more than one UN number. Which entry applies follows from the form and the concentration of the consignment — read the proper shipping name, not the CAS.
Phosphine under UN 2199 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| PHOSPHINE | 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) |
|---|---|---|---|
| Phosphine | 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).
Phosphine under UN 3525 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| PHOSPHINE, ADSORBED | 2 | 9TF | — | |
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) |
|---|---|---|---|
| Phosphine, adsorbed | 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
Phosphine — frequently asked questions
What is the CAS number of Phosphine?
The CAS number of Phosphine is 7803-51-2. Its EC number is 232-260-8.
What does a Phosphine label have to show?
Under CLP Annex VI the label for Phosphine carries the pictograms Flame, Gas cylinder, Skull and crossbones, Corrosion and Environment and the signal word is Danger.
Is Phosphine flammable?
Yes. CLP Annex VI assigns Phosphine H220 — extremely flammable gas. The flash point reported for it is NA (Gas) (NIOSH).
Is Phosphine a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Phosphine. 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 Phosphine?
The US occupational exposure limit reported for Phosphine is 0.3 [ppm] (Haz-Map, Information on Hazardous Chemicals and Occupational Diseases). 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 Phosphine?
The boiling point reported for Phosphine is -87.75 °C (-125.9 °F) (HSDB).
What is the melting point of Phosphine?
The melting point reported for Phosphine is -133.8 °C (-208.8 °F) (HSDB).
How should Phosphine be stored?
CLP Annex VI assigns Phosphine the storage statement P403. Keep container tightly closed in a dry and well-ventilated place. Contents under pressure. Storage class (TRGS 510): Gases. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Phosphine
Keep going: substances starting with P, or search the whole database by name, CAS number, pictogram or signal word.