Hazardous substances appear in far more workplaces than many people expect. Cleaning products and inks, for instance, can harm health if they are not controlled properly. The Control of Substances Hazardous to Health Regulations, otherwise known as COSHH, bring these risks into focus and require employers to follow a structured approach.
A written assessment sets out how exposure could occur and how those risks are controlled. Assessment work supports purchasing decisions, task design and maintenance planning. It also helps line managers explain to employees why specific precautions matter. When organisations treat assessments as a live reference point rather than a one-off form-filling exercise, controls stay closer to the way work is actually carried out.
How Does COSHH Law Apply in Your Business?
COSHH Regulations apply wherever a health risk caused by hazardous substances could be created. The regulations cover liquids and gases, along with vapours and dusts. Fumes and mists are also covered, as are many biological agents. Some substances are dangerous because they are toxic or corrosive. Others cause asthma, dermatitis or long term damage to organs.
Under UK law, employers must prevent or control exposure as much as reasonably practicable. These legal requirements run alongside the need for risk assessment under the Management of Health and Safety at Work Regulations. Employees and contractors fall within the protection that COSHH offers, along with others who may be affected by the work.
What Counts as a Hazardous Substance Under COSHH?
Before meaningful work on COSHH assessments can begin, organisations need a solid understanding of which substances fall within the regulations. Hazardous substances may appear in materials you buy and in mixtures created on site. They can also arise as by-products of your processes.
Examples of substances that usually fall under COSHH include:
- Cleaning products such as disinfectants, detergents and sanitisers
- Solder fluxes and welding fumes created during maintenance work
- Laboratory reagents used in analysis or research
- Dust from flour or other powdered ingredients that can be inhaled
- Biological agents found in healthcare work and some waste treatment operations
Safety data sheets provide structured information about chemical hazards and recommended controls. Labels on containers and hazard pictograms offer further guidance for users.
Why Are COSHH Assessments a Legal Requirement?
Regulators expect employers to understand how hazardous substances are used and how exposure could occur. These documents provide the formal mechanism for that work. They translate the general requirements in the regulations into specific, documented conclusions.
Inspectors use this documentation to test whether an employer has thought through the types of exposure that may arise, and the controls that are in place. Health surveillance programmes and air monitoring are easier to justify and design when assessments are structured well. Insurance providers may also request evidence that suitable documentation exists and that it is kept up to date.
Employers who ignore this documentation leave themselves exposed to enforcement action and civil claims. Where serious ill health arises and no assessment exists, it becomes difficult to show that risks were managed responsibly. Written records therefore play a central part in demonstrating that a business has met its legal obligations to protect health.
What Should a COSHH Assessment Include?
A compliant assessment follows a logical sequence. The document explains what the substance is and where it is used, then identifies who could be exposed. It then sets out how exposure could occur and how controls reduce the risk.
Information gathered typically covers:
- Identity of the substance, including product name and key hazard statements
- Tasks and locations where the substance is used or produced
- Ways in which exposure could occur through breathing, skin contact or ingestion
- Existing controls such as local exhaust ventilation and closed transfer systems, plus any personal protective equipment
- Additional measures required to reduce exposure further
Descriptions should match how work is actually carried out rather than an idealised procedure. COSHH assessments that reflect on real tasks help supervisors and employees recognise when conditions are starting to drift away from what the assessment assumes.
How do You Record COSHH Findings Correctly?
Recording assessment findings clearly is just as important as reaching the right conclusions. People who use the substances every day need to understand what it means for their tasks.
Good practice for these records includes short summaries for each task, written in plain language that operators can follow. Diagrams, photographs and annotated layouts can help where processes are complex. Maintenance records add further context, while electronic systems can help keep COSHH assessments accessible and make it easier to roll out updates when controls change.
How Assessment Findings Shape Work Decisions
COSHH assessments affect far more than compliance paperwork. The conclusions they record guide choices about equipment, process layout and task design. A clear assessment can justify enclosed filling instead of open pouring, or the move to pre-diluted products that reduce handling.
When COSHH assessments are written in language that managers and operators understand, they help people make consistent decisions under pressure. Supervisors can use them to explain why specific controls apply to particular tasks and why shortcuts create health risks. Procurement and maintenance teams can refer to assessments when specifying new equipment or when considering changes to cleaning methods or production schedules.
Warning Signs Your Documentation Needs Attention
Written assessments do not stay accurate on their own. Changes in stock, new suppliers and revised work methods can all undermine earlier work on COSHH assessments. Near misses and health complaints may also point to gaps in controls. Rising sickness absence can send the same message.
Warning signs that this documentation needs attention include:
- Regular use of temporary workarounds during chemical handling or cleaning tasks
- Repeated questions from employees
- Inspection findings that highlight poor storage
- New substances appearing on site without updated documentation
When these signs appear, it is important to check whether the assessment still reflects current work and to complete new COSHH assessments where gaps are found.
Strengthening COSHH Assessments With Specialist Input
To review or develop this documentation for your site, contact us and arrange a focused discussion about your substances, tasks and existing controls.