A Duty Holder’s Guide to COSHH 2002
What the Control of Substances Hazardous to Health Regulations 2002 require of employers, in plain English.
What it is
COSHH requires employers to control exposure to substances that are hazardous to health, from chemicals and dusts to fumes and biological agents. The heart of it is a COSHH assessment and the control measures that follow.
Who the duty holder is
The duty holder is the employer whose work exposes people to hazardous substances.
What it requires of you
- Assess the health risks from hazardous substances used or created by the work.
- Prevent exposure where you can, or adequately control it where you cannot.
- Maintain control measures, including examining and testing local exhaust ventilation (LEV).
- Monitor exposure and provide health surveillance where it is needed.
- Inform, instruct and train employees, and keep the relevant records.
How often
| Local exhaust ventilation (LEV) thorough examination and test | At least every 14 months, more often for some processes |
| COSHH assessment review | When the work, substances or evidence change |
What happens if you don’t
Failing to control hazardous substances breaches COSHH and can lead to enforcement, prosecution and unlimited fines, as well as long-term occupational ill health such as asthma, dermatitis and cancer.
Sources: COSHH Regulations 2002, COSHH: HSE guidance
This guide is general guidance, not legal advice, and is a summary only. Duties and intervals can change and depend on your circumstances. Always check the current regulation and take competent-person advice. Last reviewed June 2026.