If your workplace involves the use or generation of hazardous substances, you are legally required to carry out a COSHH risk assessment. COSHH stands for the Control of Substances Hazardous to Health, and the regulations are designed to protect workers from illnesses caused by exposure to chemicals, biological agents, dusts, fumes, vapours, and more.
This blog is written for health and safety professionals, including EHS leads, laboratory managers, site supervisors, and facility managers across industries such as manufacturing, construction, education, laboratories, and healthcare.
In this guide, we will walk you through everything you need to know, from identifying hazardous substances and assessing exposure risks to applying effective control measures, monitoring exposure, and keeping proper records. We also include template checklists, toolbox talk tips, and a practical example to help you stay compliant and keep your workers safe.
Understanding the Basics of COSHH & Key Legal Requirements
The COSHH Regulations 2002 require employers to assess the risks to health from hazardous substances in the workplace and implement measures to prevent or control exposure. The key duties under COSHH include:
- Risk assessment of hazardous substances
- Preventing or controlling exposure
- Providing suitable PPE/RPE where needed
- Monitoring exposure levels
- Health surveillance (where appropriate)
- Training staff and keeping records
Hazardous substances under COSHH include:
- Chemicals and products classified as hazardous (e.g. cleaning agents, solvents)
- Substances generated during work activities (e.g. fumes, dusts, mists)
- Naturally occurring substances (e.g. grain dust, biological agents)
Safety Data Sheets (SDS) are essential to the COSHH process. Suppliers must provide SDS for all hazardous substances. These sheets include critical information such as:
- Hazard classification and symbols
- Toxicological data
- First aid measures
- Storage and handling instructions
- Exposure limits (WELs)
Reading and understanding SDS is vital for anyone conducting a COSHH assessment.
Identifying Hazards & Assessing Exposure
Start your COSHH risk assessment by compiling a complete inventory of all hazardous substances on-site. This includes:
- Substances used during work (e.g. glues, paints, disinfectants)
- Substances produced as part of a process (e.g. welding fumes, wood dust)
- Waste materials and by-products
Each substance in your inventory should be matched with its SDS. Review each SDS for hazard symbols, exposure limits, physical properties, and recommended controls.
Exposure routes must be carefully considered:
- Inhalation: the most common route, especially for gases, vapours, dusts, and mists.
- Skin contact or absorption: relevant for liquids and powders that can penetrate skin or cause irritation.
- Ingestion: usually accidental, through hand-to-mouth transfer.
- Injection or splashes: particularly relevant in medical or laboratory settings.
Consider who might be exposed (including non-routine users, maintenance staff, and visitors), how often, and for how long. Use EH40 Workplace Exposure Limits (WELs) to help determine whether your existing controls are sufficient.
High-risk scenarios include substances with low WELs, high volatility, or those used in confined or poorly ventilated areas.
Hierarchy of Controls & Selecting Proportionate Measures
Once risks have been assessed, controls must be selected using the hierarchy of control principle. This approach ranks control methods from most to least effective:
- Elimination – Can the hazardous substance or process be removed entirely?
- Substitution – Can it be replaced with something less hazardous?
- Engineering Controls – Include local exhaust ventilation (LEV), fume hoods, or enclosed systems.
- Administrative Controls – Change how the task is performed to reduce exposure (e.g. reducing duration or frequency, rotating staff).
- PPE/RPE – Use of protective equipment should be a last resort and only when other controls are insufficient.
Local Exhaust Ventilation (LEV): LEV systems capture airborne contaminants at the source. They must be designed for the specific process, maintained regularly, and tested at least every 14 months under COSHH law.
RPE/PPE: When selecting RPE (Respiratory Protective Equipment) or PPE (Personal Protective Equipment):
- Ensure the right type is used for the substance and risk level
- Provide fit testing for RPE
- Train staff on correct use, cleaning, and maintenance
Substitution: Opt for products with a lower hazard classification where possible. For example, water-based paints instead of solvent-based.
Administrative Controls: Introduce time limits, safety signage, restricted access, and safe operating procedures (SOPs). These are useful where other controls aren’t feasible but should not be relied on as the sole control.
Monitoring, Health Surveillance & Review
In some cases, COSHH requires exposure monitoring or health surveillance. This is especially true when:
- There is a legal requirement (e.g. for lead, asbestos, isocyanates)
- Exposure limits are likely to be exceeded
- Controls are complex or may fail
Exposure Monitoring This can involve:
- Air sampling to measure airborne concentrations
- Surface wipe tests for residual contamination
- Biological monitoring (e.g. urine or breath tests)
Health Surveillance This is required when exposure may lead to ill health and there is a recognised health outcome. Examples include:
- Lung function tests for workers exposed to isocyanates
- Skin checks for dermatitis from chemical use
- Blood lead levels for lead workers
You must also regularly review your COSHH assessments. Triggers for review include:
- Introduction of new substances or processes
- Changes to WELs or regulations
- New information from SDS or HSE guidance
- Accidents, near-misses, or exposure incidents
Record Keeping, Training, and Communication
Keeping detailed records is both a legal obligation and a best practice.
What to Keep:
- Completed COSHH risk assessments
- Up-to-date SDS for all substances
- Exposure monitoring results and reports
- Health surveillance records (securely stored)
- Training logs and induction materials
Training: All workers who may come into contact with hazardous substances must be trained on:
- The hazards of the substances they work with
- How to follow safe systems of work
- Proper use of PPE and RPE
- Emergency procedures (e.g. spills, exposure)
Toolbox talks are a great way to reinforce COSHH topics. Keep them focused, relevant to the task, and backed with visual aids.
Clear communication is essential. Use COSHH symbols, pictograms, and plain language signage around the workplace. Make sure staff understand what controls apply to them and why.
Checklists & Templates You Should Have
Having the right documentation in place makes COSHH compliance much easier.
COSHH Inventory Template: Tracks all hazardous substances, locations, and whether SDS is available.
COSHH Risk Assessment Template: Covers substance name, form, quantity, exposure routes, WELs, existing controls, additional controls, and risk rating.
Hierarchy-of-Control Checklist: Helps ensure higher-level controls are considered before relying on PPE.
Training / Toolbox Talk Template: Ensures consistency in staff briefings.
Monitoring & Health Surveillance Template: Tracks what is being monitored, how often, and what action is taken.
Review Trigger Template: Logs changes in processes, substances, incidents, or health data that prompt a reassessment.
Example COSHH Risk Assessment (Case Study)
Let’s consider a practical example from a small manufacturing facility that uses an epoxy resin for assembling parts.
Step 1: Inventory lists epoxy resin and hardener as hazardous substances. SDS shows skin sensitiser and respiratory irritant.
Step 2: Exposure assessed via inhalation and skin contact. Work done in a small workshop with limited ventilation.
Step 3: WEL identified from EH40; volatile content is low, but sensitisation risk is significant.
Step 4: Controls selected:
- Substitution not viable due to performance needs
- LEV system installed at workbench
- Nitrile gloves and cartridge RPE issued
- Task rotation and 15-minute breaks every 2 hours
Step 5: Monitoring scheduled twice a year; skin health surveillance set up
Step 6: Assessment to be reviewed annually or if any symptoms reported
This example shows how COSHH risk assessments must be tailored, not generic, and based on real work scenarios.
Common Pitfalls & How to Avoid Them
Many COSHH failings stem from avoidable mistakes. Here are some of the most common:
- Relying solely on PPE rather than considering upstream controls
- Using generic SDS without reviewing specific formulations or concentration risks
- Overlooking non-routine activities such as cleaning, spills, or contractor work
- Not testing or maintaining LEV systems or failing to fit test RPE
- Letting assessments go out of date or not responding to new substances or incidents
Avoiding these pitfalls can significantly reduce risk and help demonstrate proactive compliance.
How Kingfisher Professional Services Can Help
Managing COSHH properly requires expertise, time, and up-to-date knowledge. At Kingfisher, we offer practical, hands-on support for employers looking to improve or maintain COSHH compliance.
We can help with:
- Customised COSHH risk assessment templates and toolkits
- Full audits of existing COSHH documentation and controls
- Training and toolbox talks tailored to your site and workforce
- Help setting up monitoring or health surveillance programmes
- Assistance following incidents or during HSE inspections
Our team brings wide-ranging experience across multiple sectors, and we stay on top of HSE guidance so you do not have to.
Conclusion
COSHH risk assessments are not just a legal box to tick; they are a cornerstone of workplace health and safety. Done properly, they help protect workers from serious harm and shield employers from legal and reputational risk.
With the right knowledge, systems, and support in place, you can build a safer, more compliant workplace where hazardous substances are managed responsibly.
Use our templates to get started, and speak to Kingfisher if you need tailored help.