Workplaces that use chemicals, fuels, solvents, powders or other hazardous materials can face more than one type of risk at the same time. A substance may be harmful through inhalation or skin contact while also creating a fire or explosion hazard under the right conditions. This is why a DSEAR assessment should not be treated as interchangeable with a COSHH review. The two frameworks address different risks, and understanding the distinction helps businesses build controls around real workplace conditions.
Different Regulations, Different Questions
DSEAR focuses on risks from dangerous substances that can cause fires, explosions or similar incidents. This includes flammable gases and liquids as well as combustible dusts capable of creating an explosive atmosphere. HSE guidance confirms that employers must eliminate or control risks from dangerous substances where DSEAR applies.
COSHH is concerned with substances that can harm health. Exposure may arise from dust, fumes, vapours, fibres, chemicals or biological agents, depending on the work being carried out. Safety First Group’s COSHH service focuses on identifying harmful exposure and recommending appropriate prevention or control measures.
A solvent illustrates the difference clearly. Its vapour could present an inhalation risk under COSHH and, if flammable, a separate ignition risk under DSEAR. One assessment does not automatically replace the other.
Look at the Actual Process
A useful risk assessment starts with the way a substance is stored, handled and used. The same material can create different risks depending on quantity, temperature, ventilation, transfer method and surrounding equipment.
For DSEAR, this can mean identifying where flammable vapours or combustible dust may be released, considering potential ignition sources and deciding whether hazardous-area classification is required. Safety First Group states that its DSEAR service includes assessment of dangerous substances and classification of areas where explosive atmospheres may arise.
A COSHH risk assessment considers a different set of questions: who could be exposed, how exposure occurs, how long it may last and whether existing controls are effective. Depending on the process, controls might include enclosure, local exhaust ventilation, revised working methods or exposure monitoring.
Controls Should Follow the Risk
A completed assessment has little value if it simply sits in a file. The findings need to influence how work is organised.
Under DSEAR, measures may include reducing the amount of dangerous substance present, preventing releases, improving ventilation, controlling ignition sources or separating higher-risk activities. Where explosive atmospheres may occur, zoning and suitable equipment may also need consideration.
COSHH controls can include substitution, enclosure, extraction, process changes, good housekeeping and suitable personal protective equipment where necessary. The objective is to prevent exposure where reasonably practicable or otherwise achieve adequate control.
This means operations, maintenance and health and safety teams need a shared understanding of how the controls affect daily work rather than treating compliance as a separate paperwork exercise.
Workplace Changes Can Alter the Risk
Workplaces rarely remain the same. New materials are introduced, production increases, extraction equipment deteriorates, and maintenance activities temporarily change normal working arrangements.
An assessment that accurately reflected a site two years ago may no longer represent the current process. Safety First Group’s recent DSEAR guidance highlights this particularly on construction sites, where fuel storage, hot work, temporary layouts and changing work sequences can move fire and explosion risks around the site.
The same principle applies under COSHH. A new chemical, altered production method, longer shift or modified control system can change exposure. Reviews should therefore respond to meaningful workplace changes rather than being treated only as calendar-based exercises.
Consider Fire and Health Risks Together
Reviewing DSEAR and COSHH alongside each other can help businesses avoid fragmented controls. Ventilation, for example, may influence both airborne exposure and the build-up of flammable vapours, although the exact design must suit the particular hazard.
Housekeeping is another example. Fine combustible dust may create both respiratory exposure concerns and an explosion hazard. HSE specifically identifies materials such as flour and other fine organic dusts as potential explosion risks in food manufacturing.
Looking at the entire process helps teams identify where one substance creates several different risks and ensures the resulting controls do not address only one side of the problem.
Conclusion
DSEAR and COSHH often apply to the same workplace, but they protect against different hazards. DSEAR addresses risks such as fire and explosion from dangerous substances, while COSHH focuses on protecting people from harmful exposure.
Businesses handling fuels, solvents, chemicals, dusts or similar materials may therefore need to consider both frameworks to understand their full risk profile. Safety First Group provides DSEAR and COSHH assessments alongside wider occupational hygiene services, helping employers connect regulatory requirements with practical workplace controls.