Hazard statements and precautionary statements (H and P codes)

Hazard statements and precautionary statements explained

Hazard statements are standard phrases that describe the nature of a chemical hazard and, where appropriate, how severe it is. Precautionary statements are recommended measures to minimize or prevent harm from that hazard, as the UK Health and Safety Executive (HSE) puts it. A GHS hazard statement such as H225 "Highly flammable liquid and vapour" names the hazard. A P statement says what to do about it.

Both come from the UN's Globally Harmonized System (GHS), but GHS is a framework. The rules of the market where the product is supplied determine the legal label wording. A familiar code is a lookup key, not a universal rule. You will also see hazard statements called H phrases, hazard phrases or H-statements.

What GHS hazard statements mean

Common GHS hazard statements use an H and three digits. Here are examples with their core wording:

This is a sample, not the full list. Treat H350 as core wording. OSHA Appendix C shows the applicable statement can carry extra detail, so copy the complete text for the market you supply before it goes on a label. And the numbers are identifiers. A higher H number does not mean a worse hazard.

What GHS precautionary statements mean

Precautionary statements work the same way, with a P code and standard text. The PubChem GHS reference, run by the US National Library of Medicine, groups them as general, prevention, response, storage and disposal. Codes in those groups start P1, P2, P3, P4 and P5:

• General, such as P101 "If medical advice is needed, have product container or label at hand."
• Prevention, such as P273 "Avoid release to the environment."
• Response, such as P391 "Collect spillage."
• Storage, such as P403 "Store in a well-ventilated place." P405 concerns locked storage.
• Disposal, such as P501 "Dispose of contents/container to ..."

P501 shows why codes alone aren't finished label text. The statement is incomplete until the supplier fills in the disposal destination. Combined codes such as P305+P351+P338 join several statements into one piece of response advice (PubChem and OSHA Appendix C). P102 "Keep out of reach of children." and P273 appear in a September 2026 EU product authorisation.

PubChem also flags obsolete codes that are still in use. Being listed in an online reference doesn't prove a statement applies where you sell.

How many precautionary statements go on a label

Under GB guidance, suppliers pick the precautionary statements that fit the hazard statements on the GHS label. Normally no more than six appear, though more can be needed for the nature and severity of the hazards (HSE). That default is a GB rule for P statements. It isn't a cap on H statements or a US rule.

Signal words are separate. "Danger" and "Warning" are neither hazard nor precautionary statements.

UK and US differences

In Great Britain, GB CLP is a separate regime from EU CLP, and Northern Ireland stays under EU CLP (HSE legal overview, updated 20 May 2026). Don't assume an EU change applies in GB automatically.

In the US, OSHA's Hazard Communication Standard sets the selection rules in Appendix C. The label must show the statement text. Bare reference numbers don't count. Precautionary statements can be combined, and minor wording changes are allowed if the safety advice isn't weakened. Workplace container labels have their own options under paragraph (f). They don't always need the full shipped-container layout.

The US corrected its HazCom text in January and February 2026. Use the current eCFR version rather than an older download.

Where to find the full list

Use the list for the market you supply:

• Great Britain: hazard statements in GB CLP Annex III, precautionary statements in Annex IV
• EU and Northern Ireland: Annexes III and IV of the consolidated CLP Regulation
• United States: OSHA Appendix C, with the current text on eCFR
• The UN source text: GHS Rev.11, Annex 3 (UNECE PDF)

For a code lookup with source links, ask RegAffairs AI.