H421 · Hazard statementHarms public health and the environment by contributing to global warming

Hazard statementEnvironmentalNew in Rev.11Not adopted: US, EU, Canada, Mexico

H421 is the GHS hazard statement “Harms public health and the environment by contributing to global warming”. It is used for Hazardous by contributing to global warming (chapter 4.2), Category 1. Not adopted in US OSHA, EU CLP, Canada and Mexico. The UN GHS Rev.11 label matrix lists 1 precautionary statement for it (UN only). New in UN GHS Rev.11.

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

New in Rev.11

GHS Rev.11 (2025), Annex 3

Harms public health and the environment by contributing to global warming

UN GHS Rev.11, Annex 3, Table A3.1.3, PDF p. 307

US OSHA HCS

Not adopted

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

No matching OSHA hazard class or category (not adopted by OSHA).

EU CLP

Not adopted

EU_CLP_2025 · consolidated 1 Jul 2026

Not listed in EU CLP Annex III or IV.

Canada (EN)

Not adopted

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

Not in GHS Rev.7 (the edition the HPR incorporates).

Canada (FR)

Not adopted

WHMIS_2022 · SGH Rév.7, texte officiel

Not in GHS Rev.7 (the edition the HPR incorporates).

Mexico (ES)

Not adopted

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

NOM-018-STPS-2015 covers physical and health hazards only (no environmental hazard statements).

Hazard classes and categories

Hazardous by contributing to global warming (chapter 4.2) · Category 1

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

Pictogram: Exclamation mark (GHS07)

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.

Hazardous to the atmospheric system (chapter 4.2) (hazardous by contributing to global warming), categories 1 (PDF p. 410)
P502

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.

Change in UN GHS Rev.11

New in UN GHS Rev.11 (not in Rev.10).

Sources

Each cell in the table names the official table and page for H421. 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.