Many construction sites are built on previously developed land that may contain hazardous contamination. Former industrial sites, gasworks, fuel stations, landfills, and military land can harbour chemicals, heavy metals, asbestos, hydrocarbons, and ground gases. Disturbing contaminated soil during excavation can expose workers to serious health risks through skin contact, inhalation, and ingestion. Site investigation data must be reviewed and specific precautions taken before any ground disturbance begins.
Key Hazards
Skin contact with contaminated soil containing chemicals or heavy metals
Inhalation of toxic vapours and ground gases released during excavation
Asbestos fibres in made ground and demolition fill material
Fire and explosion risk from methane or volatile organic compounds in the ground
Control Measures
Review the site investigation report and contamination assessment before starting any excavation.
Wear the PPE specified in the COSHH assessment including gloves, coveralls, and RPE where required.
Monitor ground gas levels using calibrated portable detectors during all excavation work.
Implement dust suppression measures when excavating or moving contaminated soil materials.
Segregate contaminated soil from clean material and store in designated bunded areas.
Ensure all contaminated material is disposed of through a licensed waste carrier and receiving site.
Provide decontamination facilities including welfare with hot water and skin cleaning products.
Brief all workers on the types of contamination present and the specific precautions required.
Attend health surveillance if working regularly with contaminated land as directed by the COSHH assessment.
Remember
Not all contamination is visible or has an obvious smell — always follow the COSHH assessment.
Former industrial land can contain a wide range of hazardous substances including asbestos.
Ground gases such as methane and carbon dioxide can accumulate in excavations and confined spaces.
Strict personal hygiene is essential — wash thoroughly before eating, drinking, or leaving site.
Contaminated soil must be disposed of correctly and cannot be reused without proper testing.
Report any unusual smells, discoloured soil, or unexpected buried materials to your supervisor immediately.
Applicable Legislation: Control of Substances Hazardous to Health Regulations 2002 (COSHH) · Environmental Protection Act 1990 · CDM Regulations 2015 · Control of Asbestos Regulations 2012