Physical hazard · Self-heating substances and mixtures
H252 — Self-heating in large quantities; may catch fire
Physical hazard statements describe what the substance itself can do — explode, ignite, react, corrode metal. 2 substances with a harmonised EU classification carry this code.
01 · Wording
What H252 says
Self-heating in large quantities; may catch fire.
CLP Annex III · Physical hazards
Self-heating substances and mixtures GHS chapter 2.11
Category 2 · pictogram GHS02 (flame) · signal word Warning
Unchanged since 2009.
Present in every UN GHS edition from Rev.3 (2009) to Rev.11 (2025), with the same wording throughout.
Nine editions of the UN model text, 86 hazard statements, 19 of which ever moved. Read the full story in what changed in UN GHS Rev.11.
02 · Legal status
Where H252 is current
GHS is a United Nations model text, revised every two years, and each jurisdiction adopts a revision on its own timetable. A code can be legally current in one system and deleted in another — that is normal, not an error.
| Jurisdiction | Basis | Status of H252 |
|---|---|---|
| EU CLP | Regulation (EC) 1272/2008 CLP Annex IV, Part 2 (consolidated) | Current |
| US OSHA HazCom | 29 CFR 1910.1200 Appendix C UN GHS Rev.7 (final rule of 20 May 2024) | Current |
| US HazCom 2012 | legacy · GHS Rev.3 UN GHS Rev.3, Annex 3 | Current |
| UN GHS | Rev.11 (2025) UN GHS Rev.11, Annex 3 | Current |
Currently in force under: EU CLP, US OSHA HazCom, US HazCom 2012, UN GHS. Sources: EU CLP · US OSHA HazCom · US HazCom 2012 · UN GHS
03 · Substances
Substances carrying H252
Every entry whose harmonised CLP Annex VI classification includes this hazard statement. Substances with a reference page here open on this site; the rest open on ghssymbols.com. Of these, 2 are group entries such as “salts of picric acid” or “beryllium compounds” — Annex VI gives them no CAS number, so they are listed by Index No and have no page of their own.
- magnesium, powder or turnings Index No 012-002-00-9
- potassium iron(III) 1,3-propanediamine-N,N,N',N'-tetraacetate hemihydrate Index No 607-263-00-6
Nothing matches that filter.
All hazard statements
The full list of H-codes with the jurisdiction switch lives on the hazard statements hub. For what to do about the hazard, see precautionary statements (P-codes).
Wording quoted from the regulation named above. Substance counts come from harmonised classifications in CLP Annex VI — the statements on a real product also depend on the supplier's own classification. Always check the supplier safety data sheet.