Every workplace uses substances that can harm health, from everyday cleaning agents to mists, fumes, and biological agents produced by processes. In the UK, the Control of Substances Hazardous to Health Regulations—better known as COSHH—set out what employers and employees must do to prevent ill health from exposure. When implemented well, COSHH control measures don’t just tick a compliance box; they reduce absenteeism, prevent incidents, and create a safer, more efficient environment across factories, warehouses, schools, laboratories, and commercial sites.
Understanding COSHH: Duties, Definitions, and the Hierarchy of Control
COSHH covers a wide range of hazardous substances that can cause acute or chronic harm. These include chemicals and mixtures, fumes, vapours, mists, gases, dusts (including flour and wood dust), nanomaterials, and biological agents such as bacteria or viruses used or encountered at work. Substances created by work activities—like welding fume, diesel exhaust, or silica dust from cutting—also fall within scope. Some materials (e.g., asbestos and lead) have their own regulations, but where they’re not covered elsewhere, COSHH applies. The focus is always on health effects: irritation, sensitisation (like occupational asthma), burns, dermatitis, carcinogenicity, and systemic toxicity.
Under the regulations, employers must perform an adequate COSHH assessment, prevent or control exposure, maintain and monitor those controls, provide training and information, and arrange health surveillance where appropriate. Employees must follow procedures, use controls and PPE correctly, and report defects or symptoms promptly. At the heart of everything is the hierarchy of control—a structured approach that prioritises prevention over protection:
• Eliminate: Can the task be redesigned to remove the hazardous substance altogether?
• Substitute: Can a less hazardous formulation or delivery method (e.g., pre-saturated wipes, pellets instead of powder) be used?
• Engineering controls: Local exhaust ventilation (LEV), enclosed systems, isolation, and automated dosing minimize airborne or contact exposure.
• Administrative controls: Task rotation, written procedures, training, signage, and restricted access reduce exposure duration and likelihood.
• PPE: As the last line of defence, appropriate gloves, eye protection, RPE, and protective clothing are selected based on the substance and route of exposure.
In practical terms, a small school site might substitute a spray disinfectant known for respiratory irritation with a low-mist product, store chemicals in a locked COSHH cabinet, and train staff on decanting practices. A distribution centre may manage diesel exhaust and battery charging fumes through ventilation, traffic planning, and spill prevention for acids. In a fabrication shop, the switch to low-fume consumables, effective LEV, exposure monitoring, and RPE face-fit testing combine to control welding fume. Whatever the sector, robust, layered control aligned to real tasks—not just products on a shelf—delivers COSHH compliance that protects people and productivity.
Carrying Out a Robust COSHH Assessment: Step-by-Step and Common Pitfalls
An effective COSHH assessment is methodical, evidence-based, and tailored to the task. Start with an inventory of every hazardous substance used, produced, or released at work, including cleaning products, maintenance aerosols, adhesives, dusts from processes, and biological materials. Gather up-to-date Safety Data Sheets (SDS) from suppliers—paying close attention to hazards (Section 2), handling and storage (Section 7), exposure controls and PPE (Section 8), and stability/reactivity (Section 10). Remember, SDS guidance is generic; your assessment must address how the substance is actually used on site.
Next, analyse exposure scenarios. Who is exposed (including contractors and maintenance staff), how often, for how long, and by what routes (inhalation, skin, ingestion, injection)? Consider the form and volatility of substances, the size of particles or aerosols, and any workplace exposure limits (WELs) published in EH40. Identify special categories like carcinogens, mutagens, sensitisers, and reproductive hazards that trigger heightened controls and health surveillance. Where flammability or explosivity is a concern, factor in DSEAR requirements alongside COSHH.
Define and implement proportionate control measures: substitution, LEV or enclosures, closed transfer systems and dosing pumps, segregation, spill prevention, compatible storage, and emergency plans. Ensure RPE and PPE selection is fit-for-purpose, with face-fit tests for tight-fitting respirators. Set up monitoring and maintenance—LEV thorough examination and test, air sampling where required, and routine inspection of cabinets, hoses, and seals. Plan health surveillance for risks like dermatitis (skin checks) and asthma (respiratory questionnaires and spirometry) and keep records. Formalise training on decanting, labelling, first aid, and spill response; label decanted containers and ensure CLP-compliant signage is visible.
Avoid common pitfalls. Don’t rely on PPE alone—if an airborne risk exists, start with elimination or engineering controls. Don’t copy-paste SDS text without adapting it to task-specific conditions (temperature, scale, mixing, spray formation). Don’t overlook by-products such as welding fume or isocyanate aerosols from spraying. Don’t forget non-routine tasks like cleaning, changeovers, and emergency maintenance. Involve workers in assessments; their insights on real-world practice often reveal exposures missed in the office.
Consider a real scenario: a food manufacturer experienced coughing and wheezing among cleaners using a chlorine-based sanitiser via open buckets and hand-trigger sprays. A revised assessment introduced low-mist foam application, closed dilution equipment, local ventilation improvements, gloves and goggles matched to chemical breakthrough times, and respiratory surveillance. Incidents dropped to zero within months, demonstrating how COSHH controls tailored to the task can transform outcomes. When sourcing practical solutions that support Coshh best practice—like compatible storage, absorption media, and signage—select suppliers that understand workplace realities across UK industries.
Putting COSHH into Practice: Storage, Handling, and Equipment That Make Compliance Easier
Translating policy into daily habits is where COSHH succeeds or fails. The right equipment, layout, and routines make safe choices the easiest ones. Start with segregated storage. Use clearly labelled COSHH cabinets or hazardous substance cupboards with integrated spill sumps for acids/alkalis, pesticides, or corrosives. Store flammable liquids in fire-resistant cabinets, away from ignition sources, and limit quantities at the point of use. Keep oxidisers apart from organics, and acids away from cyanides and bleach to prevent dangerous gas releases. Ventilated cabinets or local extraction reduce vapour build-up for volatile substances.
Design for safe transfer and dispensing. Closed systems, taps and funnels with flame arrestors, drum trolleys, and chemical-resistant pumps prevent splashes and inhalation hazards. Where decanting is necessary, provide stable workbenches with bunded trays, eye wash stations, and clear, durable labels. Ensure every container—large or small—has the correct identity and hazard pictograms. Use shadow boards and colour-coding for cleaning tools to prevent cross-contamination, and provide lockable storage lockers for PPE to keep it clean and accessible.
Be ready for the unexpected. Position spill kits and drain covers where liquids are stored and handled, not locked away in a distant office. Stock absorbents compatible with the chemicals on site—universal, oil-only, and chemical absorbents—and train staff on spill response: raise the alarm, don PPE, stop the source if safe, contain and clean up, and dispose of waste appropriately. Keep SDSs and emergency contact details accessible. For airborne hazards, maintain and test local exhaust ventilation and capture systems, and log all inspections. Simple checklists—weekly cabinet checks for leaks and corrosion, visual LEV checks at the start of a shift, and expiry-date reviews for reagents—embed reliability into routine.
Small sites can keep compliance straightforward: a consolidated COSHH register, task-specific instructions at the point of use, and short refresher training sessions. Larger facilities often benefit from zoning (e.g., flammables area, corrosives area), signage at entry points, and designated waste stations with labelled drums. Across all sizes, integrating ergonomics—like height-adjustable benches or drum lifters—reduces spill risk and musculoskeletal strain. When selecting workplace solutions, look for durable, compatible materials (e.g., polyethylene bunds resistant to acids/alkalis, steel cabinets with powder-coated finishes), modular shelving for clear segregation, and mobile trolleys that bring controls to the task. UK businesses can streamline compliance by partnering with suppliers that offer coordinated solutions—cabinets, dispensers, trolleys, absorbents, signage, benches—so that risk control is baked into the layout from the start and remains practical as operations scale.
Finally, keep COSHH living and current. Review assessments when you introduce new products or processes, after incidents or near-misses, and at regular intervals. Check that controls still reflect reality: are operators using a misting spray where a gel would do? Has a temporary workaround become permanent? Are training and face-fit test records up to date? By combining sound technical controls with user-friendly equipment and routine verification, organisations turn regulatory duty into everyday safety—protecting people, safeguarding productivity, and building a culture where hazard control is second nature.
Gothenburg marine engineer sailing the South Pacific on a hydrogen yacht. Jonas blogs on wave-energy converters, Polynesian navigation, and minimalist coding workflows. He brews seaweed stout for crew morale and maps coral health with DIY drones.