H232 · Hazard statementMay ignite spontaneously if exposed to air

Hazard statementPhysicalNot adopted: Mexico

H232 is the GHS hazard statement “May ignite spontaneously if exposed to air”. It is used for Flammable gases (chapter 2.2), Category 1A, pyrophoric gas. The English wording is the same as UN GHS Rev.11 in US OSHA, EU CLP and Canada. Not adopted in Mexico. Canada’s official French text is “Peut s’enflammer spontanément au contact de l’air”. The UN GHS Rev.11 label matrix lists 6 precautionary statements for it (UN only).

Maintained by Valenc. Data checked 2026-10-20.

Heading text: UN GHS Rev.11 Annex 3. Wording can differ by jurisdiction; see the table below.

Wording by jurisdiction

UN GHS Rev.11

Same as UN

GHS Rev.11 (2025), Annex 3

May ignite spontaneously if exposed to air

UN GHS Rev.11, Annex 3, Table A3.1.1, PDF p. 303

US OSHA HCS

Same as UN

HCS 2024 · primarily GHS Rev.7, some Rev.8

May ignite spontaneously if exposed to air

29 CFR 1910.1200 App. C, matched by wording

EU CLP

Same as UN

EU_CLP_2025 · consolidated 1 Jul 2026

May ignite spontaneously if exposed to air.

EU CLP (Reg. (EC) No 1272/2008), Annex III, Part 1

Canada (EN)

Same as UN

WHMIS_2022 · GHS Rev.7 (Rev.8 for chemicals under pressure)

May ignite spontaneously if exposed to air

GHS Rev.7 Annex 3 Table A3.1

Canada: pyrophoric gases are a subcategory of Flammable Gases Category 1A since SOR/2022-272 (the former Pyrophoric Gases class and Schedule 5 Part 3 were repealed).

Canada (FR)

Adopted

WHMIS_2022 · SGH Rév.7, texte officiel

Peut s’enflammer spontanément au contact de l’air

GHS Rev.7 Annex 3 Table A3.1

Mexico (ES)

Not adopted

NOM-018-STPS-2015 · GHS 5th revised edition

Not listed in NOM-018-STPS-2015 Appendix C/D.

Hazard classes and categories

Flammable gases (chapter 2.2) · Category 1A, pyrophoric gas

UN GHS Rev.11 Annex 3, sections 1 and 2

FRGaz inflammables (chapitre 2.2) · catégorie 1A, pyrophoric gas

Pictogram: Flame (GHS02)

UN GHS Rev.11 Annex 3, section 3. Pictogram rules can differ by jurisdiction; see the GHS pictogram guide.

P statements in the UN GHS Rev.11 label matrix only

UN GHS Rev.11 only. EU CLP, US OSHA, Canada (GHS Rev.7) and Mexico assign different P statements; check the regulation for your market.

Flammable gases (chapter 2.2) (pyrophoric gases), categories 1A, Pyrophoric gas (PDF p. 346)
P210 P222 P280 P377 P381 P403

UN GHS Rev.11 Annex 3, section 3. Each table covers the categories named; a P statement may apply to only some of them. Many apply only under conditions; check the conditions for use before putting them on a label.

Related codes

H220

Change in UN GHS Rev.11

No change to the wording or the hazard classes in Annex 3 compared with Rev.10.

Sources

Each cell in the table names the official table and page for H232. Full citations, links and revision notes for UN GHS Rev.11, US OSHA, EU CLP, Canada and Mexico: Sources and revision notes.

These are regulatory phrases for labels and safety data sheets. Check them against the official source for your jurisdiction before use.