Hazardous substances

Hazardous substances include chemicals (that people make or work with directly), dust, fumes and bacteria.

Exposure can happen by breathing them in, contact with the skin, splashing them into the eyes or swallowing them. If exposure isn’t prevented or properly controlled, it can cause serious illness (including cancer, asthma and dermatitis) and sometimes even death.

Employer responsibilities

By law, employers have to control exposure to hazardous substances to prevent ill health.

Employers have to protect employees and others who may be exposed under the Control of Substances Hazardous to Health Regulations 2002 (COSHH).

If employers fail to adequately control such substances, and people become ill as a result, it may mean:

  • Lost productivity to your business
  • Possible enforcement action and prosecution
  • Civil claims from your employees

There can be positive benefits to your business from carefully following through the requirements of COSHH such as:

  • Improved productivity as a result of using more effective controls (e.g. less use of raw material)
  • Improved employee morale
  • Better employee understanding and compliance with health and safety requirements

What are hazardous substances?

Hazardous substances include:

  • Substances used directly in work activities (e.g. adhesives, paints, cleaning products)
  • Substances generated during work activities (e.g. fumes from soldering and welding)
  • Naturally occurring substances (e.g. grain dust)
  • Bacteria and other micro-organisms

Biological agents either by direct contact (i.e. farming) or indirectly by accidental exposure (i.e. air conditioning system which is poorly maintained)

Any kind of dust and any other substance including:

  • Asphyxiants
  • Pesticides
  • Medicines
  • Cosmetics or
  • Substances produced in the chemical processes

Workplace exposure limits

Hazardous substances with workplace exposure limits are available on the Health and Safety Executive website.

Effects of exposure to hazardous substances

Examples include:

  • Skin irritation or dermatitis as a result of skin contact
  • Asthma as a result of developing allergy to substances used at work
  • Losing consciousness as a result of being overcome by toxic fumes
  • Cancer, which may appear long after the exposure to the chemical that caused it
  • Infection from bacteria and other micro-organisms (biological agents)

8 steps to working with hazardous substances

Step 1: Assess the risks

Identify hazardous substances present in the workplace, which may include:

  • Substances supplied to you
  • Substances produced by work activity (e.g. fumes, vapours, aerosols)
  • Final products and waste materials

Consider what risks these substances are to people’s health (this may need some research and reference to data sheets etc).

Step 2: Decide what precautions are needed

If you identify significant risks, decide on the action you need to take to remove them or reduce them to acceptable levels.

Compare any control systems you already use with good work practices and industry standards.

Remember to check that your control systems work and are effective.

Consider whether the substance could be absorbed through the skin.

Keep a record of the main findings and the actions taken to protect people.

Make a record even if it poses little or nor risk, to show it has been considered.

You should review the assessments when something changes (e.g. the substance is no longer used, or the work has changed)

Step 3: Prevent or adequately control exposure

You must prevent your employees being exposed to hazardous substances if it is reasonably practicable to do so.

You might do this by:

  • Changing things so that the substance is not needed or generated
  • Replacing it with a safer alternative
  • Using it in a safer form (e.g. pellets instead of powder)

Where preventing exposure is not reasonably practicable, then you must adequately control it.

You should consider and put in place measures including, in order of priority, one or more of the following:

Use appropriate processes, systems and engineering controls (e.g. use processes that minimise the amount of material used or equipment which totally encloses the process)

Control exposure at source and reduce:

  • The number of employees coming into contact with the substance, to a minimum
  • The level and duration of any exposure
  • The quantity of hazardous substances used or produced in the workplace
  • Provide personal protective equipment (e.g. suits, masks, respirators) as a last resort.

Step 4: Ensure control measures are used and maintained

Employees must be trained to enable them to report defects to the systems in place.

This also applies to items such as local exhaust ventilation, which have to be checked regularly to ensure they are still working effectively.

Step 5: Monitor the exposure

You have to measure the concentration of hazardous substances breathed in by workers where an assessment concludes that:

  • There could be a serious health risk if control measures failed or don’t work properly
  • Exposure limits might be exceeded
  • Control measures might not be working properly

You should keep a record of any exposure monitoring you carry out for at least 5 years.

Step 6: Carry out appropriate health surveillance

Carry out appropriate health surveillance either where your assessment has shown this necessary or where COSHH sets specific requirements.

Step 7: Prepare plans and procedures to deal with accidents, incidents and emergencies

This will apply where the work activity gives rise to a risk of an accident, incident and emergency, involving hazardous substances, which goes well beyond the risks associated with normal day to day work.

In such circumstances, you must plan your response to an emergency, involving hazardous substances, before it happens.

That means preparing procedures and setting up warning and communication systems to enable an appropriate response immediately that any incident may occur.

You need to ensure that information on your emergency arrangements is available to those who need to see it, including the emergency services. You must also practise safety drills at regular intervals.

If any accident, incident or emergency occurs you must:

  • Ensure that immediate steps are taken to minimise the harmful effects
  • Restore the situation to normal
  • Inform those who may be affected

Step 8: Ensure employees are properly informed, trained and supervised

You need to provide your employees with suitable and sufficient information, instruction and training which should include:


Environmental Health Team
Chadderton Town Hall
Middleton Road
Chadderton
Oldham, OL9 6PP
Tel 0161 770 2244
Fax 0161 770 3444

See also...

Asbestos