H-codes say what a substance can do to you. P-codes say what to do about it. Both are standardised, both have official wording in every EU language, and both lose their meaning when someone paraphrases them.
Hazard statements: the H-codes
A hazard statement is assigned to a hazard class and category. It is not chosen; it follows from the classification. The code is three digits after the letter H, and the first digit tells you which family it belongs to.
- H2xx — physical hazards. Explosives, flammability, oxidising properties, gases under pressure, corrosivity to metals.
H225is “Highly flammable liquid and vapour”.H272is “May intensify fire; oxidiser”. - H3xx — health hazards. Acute toxicity, corrosion and irritation, sensitisation, mutagenicity, carcinogenicity, reproductive toxicity, target organ toxicity, aspiration.
H314is “Causes severe skin burns and eye damage”.H350is “May cause cancer”. - H4xx — environmental hazards. Aquatic toxicity, acute and chronic, and hazards to the ozone layer.
H410is “Very toxic to aquatic life with long lasting effects”.
Some codes carry a suffix that narrows the route or the effect: H350i is “May cause cancer by inhalation”, and H360D is the reproductive toxicity statement limited to effects on the unborn child. The suffix is part of the code; dropping it changes the meaning.
EUH codes are a separate set. They are European supplementary statements with no direct GHS equivalent — for example EUH071, “Corrosive to the respiratory tract”. They appear alongside H-codes and are equally required where they apply.
Precautionary statements: the P-codes
Precautionary statements are grouped by what they are for, and the first digit again gives the family.
- P1xx — general.
P101: “If medical advice is needed, have product container or label at hand.” - P2xx — prevention.
P210: “Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.”P280: “Wear protective gloves/protective clothing/eye protection/face protection.” - P3xx — response.
P301+P310: “IF SWALLOWED: Immediately call a POISON CENTER/doctor.” - P4xx — storage.
P403+P233: “Store in a well-ventilated place. Keep container tightly closed.” - P5xx — disposal.
P501: “Dispose of contents/container to …”
Two features of P-codes catch people out. First, many are combined, written with a plus sign — P305+P351+P338 is one statement, not three, and must be reproduced whole. Second, several contain square brackets or ellipses that the supplier is expected to complete: P501 is incomplete until the disposal route is filled in for the destination. A sheet that leaves the placeholder unfilled has not finished the job.
Why the wording is not yours to change
The text of each statement is fixed in every official EU language in Annexes III and IV to CLP. The point is that a worker, an inspector or an emergency responder in any Member State reads exactly the same sentence.
This has a direct consequence for translation. Translating “Causes severe skin burns and eye damage” freshly into German produces a sentence that is not the official German text, and to an inspector that reads as an error rather than as a stylistic choice. The correct approach is to take the official wording for the destination language, not to translate.
It also means that the codes are more reliable than the prose. If you are checking a document, compare H225 against H225. Comparing “highly flammable liquid” against “very flammable liquid” tells you nothing about whether the classification agrees.
Selecting precautionary statements
CLP limits the number of precautionary statements that normally appear on a label to six, unless more are needed to reflect the nature and severity of the hazards. The selection is a judgement: choosing which six matters, and choosing badly leaves the most relevant advice off the label.
A safety data sheet is not a label and is not subject to that limit — section 2 of the sheet carries the label elements, while sections 4 through 8 carry the fuller advice.
Reading them on a MolGod card
Every substance page shows the hazard statement codes with their official text, the pictograms and the signal word, and states whether the classification comes from a harmonised Annex VI entry or from the cited sources. Harmonised classification is explained here, and you can search the catalogue by CAS number to see the codes in place.
Legal basis: Regulation (EC) No 1272/2008 (CLP), Annex III (hazard statements) and Annex IV (precautionary statements), as amended. Official wording in each language is given in those annexes.