What do hazard statements and H-codes mean?
Updated · UK law and HSE guidance
Short answer
A hazard statement is standard wording describing the nature and, where appropriate, severity of a chemical hazard. Its H-code is a reference such as H315 for skin irritation. H-codes help identify hazards on labels and safety data sheets, but they do not measure task-specific exposure or replace a COSHH assessment.
| H-code format | H followed by three digits |
|---|---|
| H200 series | Physical hazards |
| H300 series | Health hazards |
| H400 series | Environmental hazards |
| GB CLP signal words | Danger or Warning |
| Assessment status | Hazard input, not a measure of workplace risk |
How to read an H-code
The code provides a compact reference to prescribed hazard wording. For example, H300 means “Fatal if swallowed”, while H315 means “Causes skin irritation”. The statement, pictogram and signal word form part of the classification and labelling information. Codes are useful for databases and assessments, but workers should receive the full wording rather than an unexplained number.
- H2xx identifies physical hazards
- H3xx identifies health hazards
- H4xx identifies environmental hazards
- Combined statements can describe linked routes or effects
Where the information appears
Find hazard statements on the product label and in the supplier's safety data sheet, particularly the hazard-identification section. Confirm that the product and revision match what is actually used. A process can also create hazardous substances that have no supplier label, such as welding fume or silica dust, so inventorying labelled containers alone is insufficient.
- Use current SDS information from the supplier
- Check product identifiers and concentration
- Consider all statements, not only those used by a simplified control-banding tool
Using H-codes in a COSHH assessment
Hazard classification describes the substance or mixture; risk depends on how exposure occurs during the task. Combine the H-statements with quantity, form, route, duration, frequency, controls and people exposed. Physical and environmental hazards may fall outside a health-focused COSHH tool but still require management under other duties. Recheck the assessment when classification or formulation changes. SitePaper can place hazard statements into a task-specific COSHH assessment for competent review.
- Do not infer exposure solely from a severe classification
- Do not treat absence of a label as proof that a process emission is safe
- Explain control and emergency measures in language workers understand
Sources
- HSE: Hazard statements, precautionary statements and signal words
- HSE: COSHH, CLP and REACH
- HSE: COSHH technical basis and H-statements
This guide summarises UK law and HSE guidance for small businesses. It is not legal advice; check the sources and your own circumstances.