COSHH, which stands for Control of Substances Hazardous to Health, is a set of regulations designed to prevent or control exposure to hazardous substances in the workplace, including chemicals, dust, fumes, vapors, gases, and biological agents.

Understanding how to control and manage them safely is essential to prevent injury and remain compliant.

In this comprehensive guide, we answer the most commonly searched COSHH questions in the UK.

Basics and Definitions

COSHH stands for Control of Substances Hazardous to Health. It is the UK regulatory framework that requires employers to control exposure to hazardous substances.

Hazardous substances include:

  • Chemicals
  • Dusts and fumes
  • Biological agents
  • Vapours and gases
  • Nanomaterials and certain workplace mixtures

COSHH covers identification, risk assessment, control, monitoring and health surveillance related to hazardous substances.

Legal Responsibilities and Compliance

Employees who work with or may be exposed to hazardous substances should receive COSHH training.

While there is no specific COSHH training certificate required by law, employers must ensure workers are competent and informed.

Employers must:

  • Assess exposure risks
  • Implement control measures
  • Provide PPE where necessary
  • Maintain safety data records
  • Provide training and supervision

Refresher training is typically recommended every 1–3 years or when new substances are introduced.

Yes. Employers must carry out risk assessments before hazardous substances are used in the workplace.

Health Risks and Effects

Exposure may lead to:

  • Respiratory illness
  • Skin irritation
  • Eye damage
  • Long-term organ damage
  • Occupational diseases

Some substances are classified as carcinogenic or toxic if exposure is uncontrolled.

Symptoms may include:

  • Coughing
  • Skin redness
  • Eye irritation
  • Headaches
  • Breathing difficulties

Risk Assessments and Control Measures

A COSHH risk assessment evaluates hazardous substance exposure risks and determines appropriate control measures.

Steps include:

  1. Identify hazardous substances
  2. Review safety data sheets
  3. Evaluate exposure risks
  4. Implement control measures
  5. Monitor effectiveness

Consider:

  • Substance toxicity
  • Exposure duration
  • Work environment
  • Ventilation
  • Handling procedures

High-risk substances and frequent exposure activities should be prioritised.

PPE and Control Equipment

Depending on risk, PPE may include:

  • Gloves
  • Respiratory protection
  • Eye protection
  • Protective clothing

No. The hierarchy of control prioritises elimination and substitution before PPE.

Employers should provide suitable storage, handling equipment and protective devices where required.

High-risk substances and frequent exposure activities should be prioritised.

Training and Competence

Yes. Workers must understand hazardous substance risks and safe handling procedures.

Basic awareness training often takes 1 day or less.

Refresher training is recommended every 1–3 years or when processes change.

High-risk substances and frequent exposure activities should be prioritised.

Looking To Start?

If your organisation works with hazardous substances, professional COSHH training can help protect employees, improve safety culture and demonstrate regulatory compliance. For specialist COSHH training, please visit our COSHH Training course page.

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Paula Coster
Paula Coster
BA (Hons), MSc.
Associate Member CIEHF
Published On: February 24th, 2026
Last Updated: June 23rd, 2026
Categories: COSHH, Health and Safety