Substance profile
Propylene
Propylene is a colorless gas and is odorless.
01 · Identification
What Propylene is
Propylene is a colorless gas and is odorless. Its molecular formula is C3H6 and its molecular weight is 42.08 g/mol. It boils at -47.7 °C, melts at -185 °C.
Under the GHS it carries the signal word Danger. It is classed as flammable agents - 4th degree.
02 · Identifiers
Propylene identifiers and molecular data
Propylene CAS number and EC number
Propylene molecular formula and molecular weight
Other names for Propylene
- propene
03 · GHS classification
Propylene hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Propylene pictograms and signal word
Propylene hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Flammable gases GHS chapter 2.2 | Category 1A | H220 | GHS02 |
Propylene hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H220 | Extremely flammable gas. |
This page lists only the codes assigned to Propylene. 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 Propylene
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 Propylene 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
Propylene precautionary statements
CLP Annex VI assigns 3 precautionary statements to Propylene. 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.
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
Propylene 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 | пропен пропилен |
| Spanish español | Propeno propileno |
| Czech čeština | propen propylen |
| Danish dansk | propen propylen |
| German Deutsch | Propen Propylen |
| Estonian eesti | propeen propüleen |
| Greek ελληνικά | προπένιο προπυλένιο |
| English English | propene propylene |
| French français | propène propylène |
| Croatian hrvatski | propen propilen |
| Italian italiano | propilene |
| Latvian latviešu | propēns propilēns |
| Lithuanian lietuvių | propenas propilenas |
| Hungarian magyar | propén propilén |
| Maltese Malti | propen propilen |
| Dutch Nederlands | propeen propyleen |
| Polish polski | propen propylen |
| Portuguese português | propeno propileno |
| Romanian română | propenă propilenă |
| Slovak slovenčina | propén propylén |
| Slovenian slovenščina | propen propilen |
| Finnish suomi | propeeni propyleeni |
| Swedish svenska | propen propylen |
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
Propylene GHS label elements
Everything CLP Annex VI fixes for Propylene, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Propylene
- Extremely flammable gas.
- Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
- Keep container tightly closed.
- Store in a well-ventilated place.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Propylene in the GHS label constructor →
07 · Health hazards
Propylene health hazards and exposure limits
Propylene hazard summary
Simple asphyxiant Evaporating liquid can cause frostbite; Inhalation of high concentrations can cause CNS depression; [ICSC]
Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
Propylene carcinogenicity classification
Under the conditions of these studies, there was no evidence of carcinogenicity in male and female F344/N rats or in male and female B6C3F1 mice exposed to propylene by inhalation at concentrations of 5,000 or 10,000 ppm for 103 weeks. In the nasal cavity, propylene induced squamous metaplasia of the respiratory epithelium in male and female rats and epithelial hyperplasia in female rats.
Source: US National Toxicology Program · TR-272: Toxicology and Carcinogenesis Studies of Propylene (CASRN 115-07-1) in F344/N Rats and B6C3F1 Mice (Inhalation Studies) (1985 )
Evaluation: There is inadequate evidence in humans for the carcinogenicity of propylene. There is inadequate evidence in experimental animals for the carcinogenicity of propylene. Overall evaluation: Propylene is not classifiable as to its carcinogenicity to humans (Group 3).
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.
08 · Physical and chemical properties
Propylene 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.
Propylene boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | -47.68 °C (-53.8 °F) | HSDB | |
| -47.72 °C (-53.9 °F) | at 760 mmHg | CAMEO | |
| -48 °C (-54.4 °F) | ICSC |
Propylene melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -185.3 °C (-301.5 °F) | HSDB | |
| -185.22 °C (-301.4 °F) | CAMEO | ||
| -185 °C (-301 °F) | ICSC |
Propylene density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.5 g/cm³ | ICSC | |
| 0.5139 g/cm³ | at 20 °C, liquid | HSDB | |
| 0.505 g/cm³ | at 25 °C, at 760 mmHg | HSDB |
Propylene solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Very soluble in water | HSDB | |
| In water, 44.6 mL gas/100 mL at 20 °C | at 20 °C | HSDB | |
| In water, 200 mg/L at 25 °C | at 25 °C | HSDB |
Propylene vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 7600 mmHg | at 19.8 °C | HSDB |
| 8690 mmHg | at 25 °C | HSDB | |
| 8686 mmHg | at 25 °C | ICSC |
Propylene flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | -107.78 °C (-162 °F) | HSDB |
Propylene autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 455 °C (851 °F) | HSDB | |
| 460 °C (860 °F) | ICSC |
Propylene lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 2.4 % by volume | HSDB | |
| 2 % by volume | CAMEO |
Propylene upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 10.3 % by volume | HSDB | |
| 10.1 % by volume | HSDB | ||
| 11.1 % by volume | CAMEO |
Propylene vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 1.5 (air = 1) | ICSC | |
| 4.46 (air = 1) | OSHA | ||
| 1.46 (air = 1) | at 0 °C, Air = 1.0 | HSDB |
Propylene odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | ... between 39.6 and 116.27 mg/cu m. | HSDB | |
| Propylene has odor thresholds of 10-50 mg/cu m (detection) and about 100 mg/cu m (recognition), and an organoleptic limit of 0.5 mg/L. | HSDB | ||
| Odor Threshold Low: 23.0 [ppm] | Haz-Map |
Propylene critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 91.75 °C (197.2 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Propylene 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.
Propylene fire potential
Flammable gas and very dangerous fire hazard when exposed to heat, flame, or oxidizers.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Propylene storage and handling
Propylene safe storage
Fireproof. Cool.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Propylene 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)
Propylene incompatible materials
Propylene ... reacts vigorously with oxidizing materials. Under unusual conditions, eg, 96.8 MPa (995 atm) and 600 K, it explodes. It reacts violently with NO2, N2O4, and N2O. Explosions have been reported when liquid propylene contacts water at 315-348 K.
Source: Hazardous Substances Data Bank (HSDB)
Propylene reactivity
During an experiment to produce lactic acid by oxidizing PROPYLENE with nitrogen peroxide, a violent explosion occurred. These mixtures (olefins and nitrogen peroxide) form extremely unstable nitrosates or nitrosites (Comp. Rend. 116:756 1893). Contact of very cold liquid propylene with water may result in vigorous or violent boiling of the product and extremely rapid vaporization due to the large temperature differences involved. If the water is hot, there is the possibility that a liquid "superheat" explosion may occur. Pressures may build to dangerous levels if liquid propylene contacts water in a closed container.
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Propylene in the storage compatibility matrix →
11 · Transport
Propylene 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.
Propylene under UN 1077 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| PROPYLENE | 2 | 2F | — | |
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) |
|---|---|---|---|
| Propylene see also Petroleum gases, liquefied | 2.1 | — | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 2.1 is “Flammable gas” (49 CFR 173.2).
12 · Questions
Propylene — frequently asked questions
What is the CAS number of Propylene?
The CAS number of Propylene is 115-07-1. Its EC number is 204-062-1.
What is the chemical formula of Propylene?
The molecular formula of Propylene is C3H6 and its molecular weight is 42.08 g/mol.
What does a Propylene label have to show?
Under CLP Annex VI the label for Propylene carries the pictograms Flame and Gas cylinder and the signal word is Danger.
Is Propylene flammable?
Yes. CLP Annex VI assigns Propylene H220 — extremely flammable gas. The flash point reported for it is -107.78 °C (-162 °F) (HSDB).
Is Propylene a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Propylene. 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. IARC places it in Group 3: not classifiable as to its carcinogenicity to humans.
What is the boiling point of Propylene?
The boiling point reported for Propylene is -47.68 °C (-53.8 °F) (HSDB).
What is the melting point of Propylene?
The melting point reported for Propylene is -185.3 °C (-301.5 °F) (HSDB).
How should Propylene be stored?
CLP Annex VI assigns Propylene 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 Propylene
Keep going: substances starting with P, or search the whole database by name, CAS number, pictogram or signal word.