Health and Safety Executive

Substances hazardous to health

What is the risk?

If these substances are not adequately controlled, exposure can result in ill health. The type of ill health will depend on the substance: some can cause irritation of the skin or lung; some can cause more serious effects, such as asthma or cancer. Young people are not physiologically at any greater risk from exposure to such substances than anyone else. However, young people may lack awareness of the hazards and risks that they may encounter, and this awareness must be attained through careful training.

How to avoid the risk

These substances fall within the scope of COSHH. If possible, use a safer substance or change the process to avoid its use. If this is not possible, you must assess the health risks arising from work with any of the substances, and put in place measures to control the risks. One way to decide if controls are adequate is to use this chart from the COSHH Regulations:

flow chart showing decision tree regarding the assessment of hazardous substances

To assess the risk, consider:

  • The hazards of substances or their ingredients – read the labels and safety data sheets. If in doubt, contact your supplier. Don’t forget that some hazardous substances can be generated by a process, eg wood dust from a sanding operation.
  • The route into the body (breathed in, swallowed or taken in through the skin). What would be the result of exposure by each of these routes?
  • The concentration or conditions likely to cause ill health.
  • The first symptoms of over-exposure. Could exposure cause asthma, dermatitis or other health effects?
  • Who could be exposed? Don't forget maintenance workers, contractors and members of the public.
  • How often do people work with, or are exposed to, the substance?
  • How much of the substance do they work with, and for how long?
  • Could people be exposed accidentally, eg while cleaning, through spillage or if your controls fail?

Once you have assessed the risks, you must follow the principles of good practice for the control of exposure to substances hazardous to health. Control measures include:

  • changing the process;
  • containment;
  • systems of work;
  • cleaning;
  • extraction;
  • personal protective equipment.

In addition, many substances have workplace exposure limits (WELs). They are listed in EH40 Workplace exposure limits.

Further reading

Relevant legislation

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Updated 18.11.11