To deliver healthy and safe working lives and contribute to productive enterprises

Biological Monitoring

What is Biological Monitoring?

Biological monitoring is a method of assessing exposure to hazardous chemical substances by measuring the substance, its metabolites (breakdown products), or another suitable indicator in biological samples such as blood, urine or exhaled breath. It is used to determine how much of a substance has actually entered a worker's body.

Biological monitoring can provide valuable information about exposure that may not be identified through air monitoring alone, particularly where chemicals can be absorbed through the skin or ingested. It is one element of a broader occupational health and health surveillance programme.

Biological monitoring is not a substitute for controlling exposure. Employers must first eliminate or reduce exposure risks through prevention and control measures.

Why is Biological Monitoring Used?

Biological monitoring may help employers:

  • Assess whether workplace control measures are effectively preventing exposure.
  • Identify exposure through all routes, including inhalation, skin absorption and ingestion.
  • Detect excessive exposure at an early stage.
  • Meet specific legal requirements where biological monitoring is mandated by legislation, for example in certain circumstances involving occupational exposure to lead and its ionic compounds.
  • Support occupational health and health surveillance programmes.
  • Verify the effectiveness of personal protective equipment and safe working practices where appropriate.

Biological monitoring is particularly useful when a substance can enter the body through multiple routes and where air monitoring alone may not provide a complete picture of exposure.

Employer Responsibilities 

When establishing a biological monitoring programme employer’s should:

  • Clearly define the purpose of the programme.
  • Consult workers and their representatives.
  • Ensure confidentiality of personal medical information.
  • Seek advice from an occupational physician or occupational health professional.
  • Ensure workers receive information on the purpose and significance of monitoring.
  • Use the results to review and improve exposure controls where necessary. [hsa.ie], [hsa.ie]

Biological monitoring does not replace the need for risk assessment, elimination of hazards or exposure control measures.

Further Information