Hazardous substances

Information on the common issues around hazardous substances in the workplace

Common hazardous substances

Hazardous substances can include:

  • biological agents – such as fungi, bacteria, viruses
  • natural substances – such as grain, flour or enzyme dusts
  • substances generated by work – such as soldering or welding fumes, or wood dust
  • chemical products used or produced at work – such as adhesives or cleaning agents

These can be present in your workplace from a variety of sources, including:

  • gas – such as chlorine or carbon monoxide
  • liquid – such as degreasing solvent or cleaning chemicals
  • spray or mist – such as paint and epoxy sprays and acid mists
  • fumes – such as welding, hot rubber, soldering, galvanising fumes
  • vapour – such as solvent vapour released from adhesives, paints or inks
  • dust, powder or paste – such as wood, cement, metal, flour, grain, rubber or stone dust

The video below can be used and shared with your employees to help raise awareness and encourage discussion on the hazardous substances.

Workplace Exposure Limits (WELs)

Hazardous substances can have an effect when they come into contact with the human body. Many of these substances will carry WELs. Exposure to substances can occur through:

  • ingestion
  • contact with the skin
  • breathing in substance
  • injection through a puncture in the skin

You can find out more ab​out WELs on the Health and Safety Executive (HSE) website.

Skin contact

Direct skin contact from using a substance can happen through:

  • using a product
  • accidental contact such as a splash
  • inadvertent contact such as using a cloth with a substance already on it

This can result in:

  • burns
  • dermatitis
  • skin cancers
  • eye damage

Other forms of contact

Damage to the body also comes from inhalation, injection or ingestion of the substance which can result in:

  • bronchitis
  • lung cancers
  • airway obstruction
  • lung diseases such as asthma

Or damage to internal organs, causing:

  • nervous system diseases
  • cancer in other parts of the body
  • disorders of reproductive organs

Who is at risk?

Workers can be exposed to hazardous substances depending on their work activity. Here are some examples.

  • Hairdressers, through hairdressing products that can damage skin and lungs.
  • Healthcare, animal care and agricultural staff, through exposure to biological agents.
  • Cleaners, through cleaning materials that cause localised burns and skin complaints.
  • Bakery workers, through flour dust that causes irritation of eyes and nose, skin problems and asthma.
  • Welders, garage and engineering workers, through paints, solvents, oils and grease, exhausts and other fumes.
  • Construction trades workers, through exposed to fumes and dusts and specific hazards such as lead and asbestos.

The Control of Substances Hazardous to Health Regulations (COSHH) place duties on you to take measures to prevent or control the exposure. There are also specific regulations relating to lead (external site) and asbestos (external site).

Carry out a risk assessment

To help identify if there could be a hazard, you need to consider if any products you use have danger labels or signs. For example:

  • toxic
  • irritant
  • harmful
  • corrosive
  • very toxic

You also need to consider if any of the products you use:

  • have safety data sheets or other warnings
  • gives off dust, mist, spray, splashes, fumes, smoke or gases
  • have safety information in your trade association or trade magazine
  • have people coming into contact with it by touch, breathing it in or ingesting it

Your workplace risk ​assessment​ should identify if hazardous substances are used or generated in the workplace.

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COSHH assessment

You may then need to carry out a more specific assessment of the risk posed to workers and the controls you will need to put in place to protect them. This is known as a COSHH assessment.

We have created a publication with guidance and a form to help you carry out a COSHH assessment.

​Find out more

The HSE website has further information and guidance including hazardous substances at work (external site) and COSHH Essentials (external site).