What is a COSHH assessment?

Updated 2026-10-04 · UK law and HSE guidance

Short answer

A COSHH assessment identifies hazardous substances created or used at work, considers how people may be exposed and harmed, and specifies measures to prevent or adequately control exposure. It must be suitable for the actual task. A supplier's safety data sheet supplies useful hazard information but is not itself a COSHH assessment.

Key facts
Main law	Control of Substances Hazardous to Health Regulations 2002
Scope	Products and process-generated dusts, fumes, vapours, mists, gases and biological agents
Record threshold	Significant findings where 5+ people are employed
Assessor	A competent person; no universal qualification required
SDS status	Information source, not a risk assessment

Identify substances and exposure

List purchased products and substances generated by work, such as wood dust, respirable crystalline silica or welding fume. Read labels and current safety data sheets, but also observe the task. Consider inhalation, skin and eye contact, ingestion and accidental injection. Note quantity, concentration, physical form, frequency, duration and everyone who may be exposed, including cleaners and maintenance staff.

Include routine, cleaning, spill and disposal activities
Check section 8 of the SDS for exposure controls and limits
Identify health effects, routes of exposure and people at increased risk

Prevent or adequately control exposure

First ask whether the substance or process can be eliminated or replaced with a safer alternative. Where it cannot, use suitable processes, engineering controls and local exhaust ventilation before relying on respiratory or other personal protective equipment. Compare relevant exposure with any workplace exposure limit, while remembering that staying below a limit does not remove the duty to control exposure adequately.

Specify storage, handling, cleaning and waste controls
Set examination, maintenance and testing arrangements
Provide information, instruction, training and emergency procedures
Arrange monitoring or health surveillance where the Regulations require it

Record and review the assessment

Record the substance, task, people, exposure routes, controls and further actions. The assessor needs enough knowledge, skills and experience to understand the work and make control decisions. Review regularly, and sooner after significant change, new hazard information, evidence of exposure or control failure. Workers must be able to understand and use the controls. SitePaper can generate a COSHH assessment draft for competent checking.

Attach or identify the current SDS without copying it as the assessment
Verify controls at the point of work
Update affected workers when the assessment changes

Sources

This guide summarises UK law and HSE guidance for small businesses. It is not legal advice; check the sources and your own circumstances.