COSHH assessments: a practical guide

For employers, compliance managers, occupational hygienists and engineers managing hazardous substances, exposure controls and COSHH evidence. It is UK-focused and not legal advice.

The Control of Substances Hazardous to Health Regulations 2002 (COSHH) require employers to assess the risks from hazardous substances and put control measures in place before work begins.

What a COSHH assessment covers

The substances used and their hazards
The routes and likely level of exposure
Who is at risk
The control measures and PPE required
Monitoring and health surveillance where needed

The hierarchy of control

Exposure must be prevented where it is reasonably practicable to do so, or otherwise adequately controlled, applying the principles of good control practice and the workplace exposure limits.

Maintaining and testing controls

Control measures such as local exhaust ventilation (LEV) must be maintained, and thoroughly examined and tested at least every 14 months, more often for certain processes.

COSHH on CertFlow

CertFlow links each substance to its assessment, safety data sheet, storage location and the PPE required, so the control measures are visible wherever the substance is used.

What inspectors commonly see

No COSHH assessment for substances in use, or assessments not tied to the actual task

Local exhaust ventilation (LEV) overdue its thorough examination or underperforming

Missing or out-of-date safety data sheets

No exposure monitoring or health surveillance where it is needed

Control measures in place on paper but not maintained in practice

Common mistakes

Filing safety data sheets without carrying out a task-specific COSHH assessment.

Specifying PPE without checking whether exposure can be prevented or better controlled.

Missing LEV thorough examination dates or not acting on poor performance.

Failing to review assessments after a substance, process or exposure route changes.

Not recording training, health surveillance or monitoring where needed.