What Substances Are Covered by COSHH?

When people think about COSHH, they often think of chemicals stored in bottles or containers displaying hazard symbols. While these products can certainly fall under COSHH, the regulations cover a much wider range of substances that may be hazardous to health.

Under the Control of Substances Hazardous to Health Regulations (COSHH), employers need to consider substances that could cause harm through workplace exposure. These can include chemicals, dusts, fumes, vapours, mists, gases and biological agents.

Importantly, hazardous substances may also be generated by the work itself. This means employers need to consider not only the products they purchase, but also the substances created by workplace processes.

What is a substance hazardous to health?

A substance hazardous to health is one that has the potential to cause harm through workplace exposure.

Depending on the substance and exposure involved, potential health effects can include skin or eye irritation, dermatitis, occupational asthma, respiratory conditions and other short or long-term health effects.

Substances covered by COSHH can include:

• Chemicals and chemical products
• Dusts
• Fumes
• Vapours Mists and aerosols
• Gases Biological agents
• Substances generated by workplace processes

The key point is that COSHH is about potential exposure to substances that can harm health, rather than simply maintaining a list of chemicals.

The HSE provides further guidance on what is classed as a substance hazardous to health under COSHH.

Chemicals and chemical products

Many products commonly used within workplaces may contain substances hazardous to health.

Examples can include:

• Cleaning and degreasing products
• Solvents
• Paints and coatings
• Adhesives and sealants
• Lubricants and metalworking fluids
• Acids and alkalis
• Disinfectants
• Resins and hardeners

Product labels and Safety Data Sheets (SDS) provide useful information when identifying hazardous properties.

However, a Safety Data Sheet is not itself a COSHH assessment. An assessment needs to consider how the substance is actually being used and the potential for people to become exposed.

Dusts and fumes

Some hazardous substances do not arrive in a labelled container at all. Instead, they are created by workplace activities.

For example, cutting, drilling, sanding and grinding can generate potentially hazardous dusts. This may include wood dust or dust containing respirable crystalline silica.

Processes involving heating or working metals can also produce hazardous fumes, with welding fume being a common example.

These types of exposure are particularly important in manufacturing, engineering, construction and maintenance environments because they can be overlooked if an organisation focuses solely on its chemical inventory.

Vapours, mists and gases

Some liquids can release hazardous vapours, particularly where volatile products such as solvents, paints, cleaners or adhesives are used.

The way a product is applied can also affect the exposure risk. Spraying a product, for example, may create an airborne mist that presents a different exposure scenario from applying the same product manually.

Gases may also present a risk to health where they are used or generated within workplace processes.

Factors such as quantity, temperature, ventilation, duration of use and whether work takes place in an enclosed area can all influence the potential for exposure.

Biological agents

COSHH is not limited to chemicals.

Certain biological agents, including microorganisms that can cause harm to human health, may also be covered.

Exposure can arise in workplaces such as healthcare, laboratories and waste handling, but biological hazards may also be encountered incidentally through other work activities.

Substances generated by workplace activities

Process-generated substances are one of the most important areas to consider when identifying COSHH hazards.

Examples include:

• Welding creating welding fume
• Cutting concrete or stone generating silica-containing dust
• Sanding timber creating wood dust
• Machining generating metalworking fluid mist
• Spraying creating airborne mists
• Heating materials generating fumes or vapours

The original material may not necessarily present the same exposure risk as the substance created when it is processed.

This is why COSHH assessments need to consider the actual task, rather than simply copying hazard information from a Safety Data Sheet.

Does every chemical need a COSHH assessment?

Not every substance in a workplace will present the same level of risk, and COSHH should not simply become an exercise in creating paperwork for every container on site.

Employers need to consider whether substances are hazardous to health and assess the risk created by the way they are used or generated.

The same product could create very different exposure scenarios depending on the quantity used, method of application, frequency of use, ventilation and existing controls.

Our guide explaining what a COSHH assessment should include looks at the factors that need to be considered when assessing these risks.

What substances are not covered by COSHH?

Some hazardous substances have their own specific legislation and are therefore not managed under COSHH in the same way. Important examples include asbestos, lead and radioactive substances.

COSHH also specifically addresses risks to health from hazardous substances. A substance may present additional hazards that need to be managed under other legislation.

For example, a flammable substance may create both a health risk from exposure and a fire or explosion risk, meaning requirements under DSEAR may also need to be considered.

Who is responsible for identifying COSHH substances?

The employer is ultimately responsible for ensuring risks from hazardous substances are appropriately assessed and controlled, although managers, supervisors, employees and competent advisers can all have responsibilities within the organisation's COSHH arrangements.

Our guide to who is responsible for COSHH in the workplace explains these responsibilities in more detail.

Identifying hazardous substances should therefore involve looking beyond the chemical cupboard. Employers should consider the products being used, the processes taking place and the dusts, fumes, vapours, mists or other hazardous substances those activities may generate.

For organisations dealing with multiple hazardous substances or more complex exposure risks, Spiers Safety provides COSHH assessment and hazardous substance management services to help identify hazards, assess workplace exposure and establish appropriate controls.