H261 · Hazard statementIn contact with water releases flammable gas

Hazard statementPhysicalDiffers: EU

H261 is the GHS hazard statement “In contact with water releases flammable gas”. It is used for Substances and mixtures which, in contact with water, emit flammable gases (chapter 2.12), Category 2, 3. The English wording is the same as UN GHS Rev.11 in US OSHA and Canada. The wording differs in EU CLP. Canada’s official French text is “Dégage au contact de l’eau des gaz inflammables” and Mexico’s Spanish text is “En contacto con el agua desprende gases inflamables”. The UN GHS Rev.11 label matrix lists 7 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

In contact with water releases flammable gas

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

In contact with water releases flammable gas

29 CFR 1910.1200 App. C, matched by wording

EU CLP

Differs

EU_CLP_2025 · consolidated 1 Jul 2026

In contact with water releases flammable gases.

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)

In contact with water releases flammable gas

GHS Rev.7 Annex 3 Table A3.1

Canada (FR)

Adopted

WHMIS_2022 · SGH Rév.7, texte officiel

Dégage au contact de l’eau des gaz inflammables

GHS Rev.7 Annex 3 Table A3.1

Mexico (ES)

Adopted

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

En contacto con el agua desprende gases inflamables

Sustancias y mezclas que, en contacto con el agua, desprenden gases inflamables · 2, 3

NOM-018-STPS-2015, DOF 9 October 2015, Apéndice C, Tabla C.1, PDF p. 30

Hazard classes and categories

Substances and mixtures which, in contact with water, emit flammable gases (chapter 2.12) · Category 2, 3

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

FRMatières qui, au contact de l’eau, dégagent des gaz inflammables (chapitre 2.12) · catégorie 2, 3

ESSustancias y mezclas que, en contacto con el agua, desprenden gases inflamables · 2, 3 (NOM-018-STPS-2015)

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.

Substances and mixtures which, in contact with water, emit flammable gases (chapter 2.12), categories 1, 2 (PDF p. 364)
P223 P280 P501 P231+P232 P302+P335+P334 P370+P378 P402+P404
Substances and mixtures which, in contact with water, emit flammable gases (chapter 2.12), categories 3 (PDF p. 365)
P280 P501 P231+P232 P370+P378 P402+P404

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

H260

Change in UN GHS Rev.11

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

Notes

EU CLP wording differs from UN GHS Rev.11.

In the Rev.11 matrix, P223 and P302+P335+P334 are listed for Category 2 only, not Category 3.

Sources

Each cell in the table names the official table and page for H261. 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.