COSHH
Plain English. Practical detail. UK context.
COSHH means the Control of Substances Hazardous to Health Regulations. It concerns preventing or adequately controlling exposure to substances that can harm health at work. A bottle's warning label is only part of the picture: sanding, cutting, welding and other processes can create harmful substances even when nothing hazardous was purchased.
Safety: if a material might contain asbestos, leave it undisturbed and do not drill, sand or break it. Have it surveyed, and use a licensed asbestos contractor for removal: HSE requires a licence for most asbestos removal work.
Last reviewed: (editorial review against the public sources listed below).
Identify what the task creates and uses
HSE's assessment guidance identifies wood dust, silica dust and welding fume as examples of process-generated hazards. Consider liquids, pastes, dusts, vapours and other exposures relevant to the work. A tradesperson should understand who may breathe, touch or otherwise encounter the substance and how often. Homeowners should tell the contractor about occupants, access and relevant sensitive circumstances without being expected to write the contractor's assessment. Trainees should ask about unfamiliar products and processes before starting. A safety data sheet supports assessment but is not itself the complete task-specific decision.
Choose controls in the right order
HSE asks whether the substance or process can be eliminated or changed, then considers containment and effective exposure controls. Suitable extraction, methods, access arrangements and cleaning can be important. Do not automatically choose gloves or a mask as the entire solution. Protective equipment must suit the actual exposure and be used correctly within a wider system. A trainee should not sweep hazardous dust into the air or remove extraction because it slows the task. Learn the assessed method and report when controls cannot be used as intended.
Information, training and review are practical duties
Workers need to understand the findings, precautions and emergency arrangements. Controls require maintenance and relevant checks; a folder of assessments does not prove they function. HSE explains recording requirements and recommends useful written records even for smaller businesses. Review when processes, people, materials or conditions change, or evidence suggests controls are ineffective. Trainees should raise defects, symptoms or unsuitable arrangements rather than improvise. Health surveillance or exposure monitoring can be needed in relevant circumstances, but neither is a substitute for controlling the source of exposure.
Keep the scope and homeowner explanation clear
COSHH covers many harmful substances, but lead and asbestos have separate specific regulations. Other duties, including fire, environmental and dangerous-goods rules, can also apply. Explain relevant protection of occupants, work areas, storage, cleaning and re-entry for the actual task rather than promise one universal safe waiting period. Prices and outcomes vary from job to job, so compare written, itemised quotations rather than relying on a typical figure. Use the correct jurisdictional framework, including Northern Ireland arrangements where relevant. A useful tradesperson record links the substance, task and effective controls, while the homeowner receives understandable precautions and a clear contact route if conditions differ from the agreed plan.
Frequently asked questions
Is a safety data sheet a complete COSHH assessment?
No. Assess the actual task, exposure, people and controls using the relevant information.
Does COSHH only apply to labelled chemical containers?
No. Harmful dust, fume and other substances generated by work also matter.
Sources and further reading
Public sources and further reading. Sources checked: 8 November 2026. Consult the original for details and later changes.