Physical hazard · Self-heating substances and mixtures
H251 — Self-heating: may catch fire
Physical hazard statements describe what the substance itself can do — explode, ignite, react, corrode metal. 4 substances with a harmonised EU classification carry this code.
01 · Wording
What H251 says
Self-heating: may catch fire.
CLP Annex III · Physical hazards
Self-heating substances and mixtures GHS chapter 2.11
Category 1 · pictogram GHS02 (flame) · signal word Danger
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 · Languages
H251 in the 24 official EU languages
A label put on the market in an EU country must carry the wording of that country's own language version of CLP — not a translation of the English one. These 24 lines are quoted from the consolidated regulation, Annex III, and are the text to print.
| Language | Official wording of H251 |
|---|---|
| BG български Bulgarian | Самонагряващо се: може да се запали. |
| ES español Spanish | Se calienta espontáneamente; puede inflamarse. |
| CS čeština Czech | Samovolně se zahřívá: může se vznítit. |
| DA dansk Danish | Selvopvarmende, kan selvantænde. |
| DE Deutsch German | Selbsterhitzungsfähig; kann in Brand geraten. |
| ET eesti Estonian | Isekuumenev, võib süttida. |
| EL ελληνικά Greek | Αυτοθερμαίνεται: μπορεί να αναφλεγεί. |
| EN English English | Self-heating: may catch fire. |
| FR français French | Matière auto-échauffante; peut s'enflammer. |
| GA Gaeilge Irish | Féintéamh: d'fhéadfadh sé dul trí thine. |
| HR hrvatski Croatian | Samozagrijavanje; može se zapaliti. |
| IT italiano Italian | Autoriscaldante; può infiammarsi. |
| LV latviešu Latvian | Pašsasilstošs; var aizdegties. |
| LT lietuvių Lithuanian | Savaime kaistančios, gali užsidegti. |
| HU magyar Hungarian | Önmelegedő: meggyulladhat. |
| MT Malti Maltese | Jisħon waħdu: jista' jieħu n-nar. |
| NL Nederlands Dutch | Vatbaar voor zelfverhitting: kan vlam vatten. |
| PL polski Polish | Substancja samonagrzewająca się: może się zapalić. |
| PT português Portuguese | Susceptível de auto-aquecimento: risco de inflamação. |
| RO română Romanian | Se autoîncălzește, pericol de aprindere. |
| SK slovenčina Slovak | Samovoľne sa zahrieva; môže sa vznietiť. |
| SL slovenščina Slovenian | Samosegrevanje: lahko povzroči požar. |
| FI suomi Finnish | Itsestään kuumeneva; voi syttyä palamaan. |
| SV svenska Swedish | Självupphettande. Kan börja brinna. |
Source: CELEX:02008R1272-20260501, Annex III. © European Union, https://eur-lex.europa.eu — only the electronic Official Journal of the European Union is authentic. Irish is one of the 24 official languages and its H and P texts are printed inside the multilingual Annex tables, but no consolidated CLP has ever been published in Irish — which is why an Irish-primary label cannot be built here.
03 · Legal status
Where H251 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 H251 |
|---|---|---|
| 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
04 · Substances
Substances carrying H251
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, 1 is a group entry 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.
- potassium ethanolate CAS 917-58-8
- Sodium Dithionite CAS 7775-14-6
- sodium methanolate CAS 124-41-4
- zirconium powder (non pyrophoric) Index No 040-002-00-9
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.