What is COSHH?
COSHH stands for the Control of Substances Hazardous to Health. The COSHH Regulations 2002 (as amended) are the primary legal framework in the UK requiring employers to prevent or adequately control employee exposure to hazardous substances in the workplace.
The regulations apply to virtually all workplaces where hazardous substances are used, produced, or encountered — from factories and laboratories to offices, schools, and healthcare settings. Only lead, asbestos, and radioactive materials are excluded, as these are covered by their own specific regulations.
Who Must Comply with COSHH?
All employers, self-employed persons, and anyone who controls a work activity involving hazardous substances. This includes businesses of all sizes — there is no small-business exemption under COSHH.
The 8 COSHH Hazard Categories
COSHH covers a wide range of hazardous substances. Understanding the categories helps you identify what needs to be assessed in your workplace.
Substance Categories Under COSHH
| Category | Description | Common Examples |
|---|---|---|
| Chemicals | Substances classified as hazardous under CLP Regulation | Cleaning agents, solvents, adhesives |
| Fumes | Airborne solid particles from heated metals or processes | Welding fume, rubber fume, soldering flux |
| Dusts | Fine particles generated by cutting, grinding, or handling | Wood dust, silica dust, flour dust, grain dust |
| Vapours | Gaseous forms of substances that are normally liquid or solid | Paint vapours, fuel vapours, solvent vapours |
| Mists | Airborne droplets of liquid substances | Oil mist, acid mist, spray paint mist |
| Gases | Substances that are gaseous at room temperature | Carbon monoxide, chlorine, ammonia |
| Biological agents | Micro-organisms that may cause infection, allergy, or toxicity | Bacteria, viruses, fungi, parasites |
| Nanotechnology | Engineered nanoparticles and nanomaterials | Carbon nanotubes, nano-titanium dioxide |
Source: HSE COSHH Essentials Guidance (HSG97)
Don't Forget By-Products
COSHH assessments must also cover hazardous substances created by work processes — for example, wood dust from cutting timber, welding fume, or exhaust emissions. These are easily overlooked but represent significant exposure risks.
The 5-Step COSHH Assessment Process
The HSE outlines a structured 5-step approach to COSHH assessment. Following this process ensures you systematically identify and control all hazardous substance risks.
COSHH Assessment Steps
| Step | Action | Key Activities |
|---|---|---|
| 1. Identify | Identify hazardous substances | Inventory all chemicals, check safety data sheets (SDS), identify process-generated substances |
| 2. Evaluate | Assess the risks | Determine who is exposed, how, for how long, and at what concentration; consider route of entry (inhalation, skin, ingestion) |
| 3. Control | Decide on control measures | Apply the hierarchy of controls, implement engineering controls, provide PPE as last resort |
| 4. Monitor | Implement and maintain controls | Ensure controls work properly, carry out workplace exposure monitoring, provide health surveillance where required |
| 5. Review | Review the assessment regularly | Revisit when processes change, after incidents, when new substances introduced, or at least annually |
Source: HSE Guidance Note EH40 and COSHH ACoP (L5)
Each assessment must be recorded in writing if you employ five or more people. However, it is best practice to record all assessments regardless of workforce size. Assessments should be "suitable and sufficient" — proportionate to the level of risk rather than overly bureaucratic.
Competent Person Requirement
COSHH assessments must be carried out by a competent person — someone with sufficient training, knowledge, and experience to identify hazards and evaluate risks. This does not necessarily require a formal qualification, but appropriate health and safety training is strongly recommended.
Control Measures: The Hierarchy of Controls
COSHH requires employers to apply controls in a specific order of priority, known as the hierarchy of controls. You must always attempt higher-level controls before relying on lower-level measures.
COSHH Hierarchy of Controls
| Priority | Control Measure | Description | Example |
|---|---|---|---|
| 1 (Most Effective) | Elimination | Remove the hazardous substance entirely | Use a water-based process instead of solvent-based |
| 2 | Substitution | Replace with a less hazardous alternative | Use a less toxic cleaning agent |
| 3 | Engineering Controls | Isolate or enclose the process | Install local exhaust ventilation (LEV), fume cupboards |
| 4 | Administrative Controls | Change work procedures to reduce exposure | Limit exposure time, rotate workers, improve signage |
| 5 (Last Resort) | Personal Protective Equipment | Provide PPE to individual workers | Respirators, chemical-resistant gloves, goggles |
Source: HSE COSHH Approved Code of Practice (L5, 6th Edition)
PPE should never be the sole control measure where higher-level controls are reasonably practicable. Employers must provide PPE free of charge, ensure it fits properly, train workers in its use, and maintain it in good condition.
COSHH Compliance Checklist
Use this checklist to verify that your workplace meets the core requirements of the COSHH Regulations 2002. Tick off each item as you complete it.
Employer COSHH Compliance Checklist
| Area | Requirement | Regulation |
|---|---|---|
| Assessment | Completed a suitable and sufficient COSHH risk assessment for all hazardous substances | Reg. 6 |
| Assessment | Recorded assessments in writing (mandatory for 5+ employees) | Reg. 6(4) |
| Assessment | Reviews assessments regularly and after any significant changes | Reg. 6(3) |
| Control | Implemented adequate control measures following the hierarchy of controls | Reg. 7 |
| Control | Ensured workplace exposure limits (WELs) are not exceeded | Reg. 7(7) |
| Maintenance | Engineering controls (e.g., LEV) examined and tested at least every 14 months | Reg. 9 |
| Maintenance | PPE maintained in good working order and records kept | Reg. 9(5) |
| Monitoring | Workplace exposure monitoring carried out where required | Reg. 10 |
| Surveillance | Health surveillance provided for employees exposed to listed substances | Reg. 11 |
| Training | Workers informed, instructed, and trained on risks and control measures | Reg. 12 |
| Training | Safety data sheets (SDS) accessible to all relevant workers | Reg. 12 |
| Emergency | Emergency procedures in place for accidental spills or exposure | Reg. 13 |
Source: COSHH Regulations 2002 (as amended)
Employer Legal Obligations Under COSHH 2002
The COSHH Regulations 2002 place clear legal duties on employers. Failure to comply can result in enforcement action by the HSE, including improvement notices, prohibition notices, and prosecution.
Key Employer Duties
| Duty | Regulation | Requirement |
|---|---|---|
| Risk Assessment | Regulation 6 | Assess risks from all hazardous substances before work begins |
| Prevention & Control | Regulation 7 | Prevent exposure or, where not reasonably practicable, adequately control it |
| Use of Controls | Regulation 8 | Ensure employees properly use control measures provided |
| Maintenance & Testing | Regulation 9 | Maintain, examine, and test all control measures at suitable intervals |
| Exposure Monitoring | Regulation 10 | Monitor workplace exposure where assessment identifies it as necessary |
| Health Surveillance | Regulation 11 | Provide health surveillance for workers exposed to certain substances |
| Information & Training | Regulation 12 | Provide suitable information, instruction, and training to exposed workers |
| Emergencies | Regulation 13 | Prepare for accidents, incidents, and emergencies involving hazardous substances |
Source: The Control of Substances Hazardous to Health Regulations 2002 (SI 2002/2677)
Penalties for Non-Compliance
Since February 2016, health and safety offences in England and Wales carry unlimited fines for both the Crown Court and Magistrates' Court. Serious COSHH breaches resulting in injury or death can lead to custodial sentences of up to 2 years under the Health and Safety at Work etc. Act 1974. Corporate manslaughter convictions carry a maximum penalty of an unlimited fine.
Common Workplace Scenarios
COSHH risks vary significantly between industries. Here are common hazardous substances encountered across key UK sectors.
Industry-Specific COSHH Hazards
| Industry | Common Hazardous Substances | Primary Risks | Key Controls |
|---|---|---|---|
| Construction | Silica dust, cement, asbestos-containing materials | Silicosis, dermatitis, mesothelioma | LEV, wet cutting, RPE, health surveillance |
| Manufacturing | Metalworking fluids, solvents, isocyanates | Occupational asthma, dermatitis | Enclosed systems, LEV, skin protection |
| Healthcare | Glutaraldehyde, cytotoxic drugs, latex, biological agents | Sensitisation, infection, chemical burns | Closed systems, PPE, safe handling protocols |
| Agriculture | Pesticides, veterinary medicines, grain dust, zoonotic agents | Poisoning, respiratory disease, infection | Substitution, enclosed cabs, RPE, hygiene |
| Cleaning | Bleach, ammonia-based cleaners, acid descalers | Burns, respiratory irritation, sensitisation | Substitution, dilution systems, ventilation, PPE |
| Hairdressing | Hair dyes (PPD), bleaching agents, acrylates | Dermatitis, occupational asthma | Gloves, ventilation, substitute products |
| Motor Vehicle Repair | Isocyanate paints, brake dust, degreasers, exhaust fumes | Occupational asthma, cancer | Spray booths, LEV, RPE, health surveillance |
| Laboratories | Chemical reagents, biological samples, nanomaterials | Toxic exposure, infection, burns | Fume cupboards, biosafety cabinets, SOPs |
Source: HSE sector-specific COSHH guidance
Resources & Further Reading
The following resources from the Health and Safety Executive (HSE) and other authoritative bodies provide detailed guidance on COSHH compliance.
Essential COSHH Resources
| Resource | Description | Publisher |
|---|---|---|
| COSHH Essentials (HSG97) | Step-by-step guidance on COSHH assessment for small and medium businesses | HSE |
| EH40 — Workplace Exposure Limits | Table of workplace exposure limits for hazardous substances in the UK | HSE |
| COSHH ACoP (L5) | Approved Code of Practice and guidance on COSHH Regulations 2002 | HSE |
| COSHH e-tool | Free online tool to help businesses carry out COSHH assessments | HSE |
| GHS/CLP Classification | Globally Harmonised System for classifying and labelling chemicals | UN / EU |
| Safety Data Sheets (SDS) | Detailed safety information provided by chemical manufacturers and suppliers | Suppliers |
| INDG136 — COSHH Brief Guide | Free leaflet summarising employer duties under COSHH | HSE |
| HSE RIDDOR Reporting | Requirements for reporting occupational diseases linked to hazardous substances | HSE |
All HSE publications available at hse.gov.uk
Staying Up to Date
COSHH regulations and workplace exposure limits are periodically updated. Check the HSE website regularly and ensure your COSHH assessments reflect the latest WEL values published in EH40. Subscribe to HSE e-bulletins for alerts on regulatory changes.
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