P377 · Precautionary statementLeaking gas fire: Do not extinguish, unless leak can be stopped safely.

Precautionary · ResponsePhysical

P377 is the GHS precautionary statement “Leaking gas fire: Do not extinguish, unless leak can be stopped safely”. UN GHS Annex 3 assigns it to Flammable gases (chapter 2.2), Category Flammable gas, Pyrophoric gas, 1A, Chemically unstable gas A, Chemically unstable gas B, 1B, 2. The English wording is the same as UN GHS Rev.11 in US OSHA, EU CLP and Canada. Canada’s official French text is “Fuite de gaz enflammé : Ne pas éteindre si la fuite ne peut pas être arrêtée sans danger” and Mexico’s Spanish text is “Fuga de gas inflamado. No apagar las llamas del gas inflamado si no puede hacerse sin riesgo”. In the UN GHS Rev.11 label matrix it is used with 5 hazard statements (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

Leaking gas fire: Do not extinguish, unless leak can be stopped safely.

UN GHS Rev.11, Annex 3, Table A3.2.3, PDF p. 327

US OSHA HCS

Same as UN

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

Leaking gas fire: Do not extinguish, unless leak can be stopped safely.

29 CFR 1910.1200 App. C, matched by wording

EU CLP

Same as UN

EU_CLP_2025 · consolidated 1 Jul 2026

Leaking gas fire: Do not extinguish, unless leak can be stopped safely.

EU CLP, Annex IV, Part 2

Canada (EN)

Same as UN

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

Leaking gas fire: Do not extinguish, unless leak can be stopped safely.

GHS Rev.7 Annex 3 Table A3.2

Canada (FR)

Adopted

WHMIS_2022 · SGH Rév.7, texte officiel

Fuite de gaz enflammé : Ne pas éteindre si la fuite ne peut pas être arrêtée sans danger.

GHS Rev.7 Annex 3 Table A3.2

Mexico (ES)

Adopted

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

Fuga de gas inflamado. No apagar las llamas del gas inflamado si no puede hacerse sin riesgo

NOM-018-STPS-2015, DOF 9 October 2015, Apéndice D, Tabla D.1, PDF p. 37

Hazard classes and categories

Flammable gases (chapter 2.2) · Category Flammable gas, Pyrophoric gas, 1A, Chemically unstable gas A, Chemically unstable gas B, 1B, 2

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

H statements it is used with 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 their own P statements; check the regulation for your market.

H220 H221 H230 H231 H232

UN GHS Rev.11 Annex 3, section 3. Listed for at least one category that uses each H statement.

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 P377. 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.