EXC/Hazards/TBT-EXC-004

Contaminated Ground Awareness

Excavations › Hazards › Contaminated Ground Awareness

Presenter		Project
Location		Date

Contaminated ground is soil or groundwater containing harmful substances from previous industrial, military, or waste disposal use.
Contaminants commonly encountered include hydrocarbons, heavy metals, asbestos fibres, solvents, acids, and landfill gas.
Construction workers can be exposed through skin contact, inhalation of dust and vapours, and ingestion from unwashed hands.
A Phase 1 desk study and Phase 2 ground investigation should identify contamination before construction work begins.
Visual indicators include unusual soil colours, oily sheens on water, chemical odours, buried drums, and discoloured vegetation.
Ground gases such as methane and carbon dioxide migrate through soil and accumulate in excavations and enclosed spaces.
Personal gas monitors must be worn during excavation on sites with known or suspected ground contamination.
Contaminated material must be stockpiled separately on lined areas and disposed of through licensed hazardous waste facilities.
COSHH assessments must be prepared for each identified contaminant, specifying PPE, controls, and emergency procedures.
Decontamination procedures including boot washing and PPE removal stations must be set up at the boundary of contaminated areas.

Health risk	Contaminated soil causes skin disease, respiratory illness, and cancer — workers must be protected from all exposure routes.
Gas hazard	Methane from landfill and made ground accumulates in excavations, creating explosive atmospheres without warning.
Legal duty	Environmental regulations require contaminated material to be handled, stored, and disposed of as controlled waste.

Don't

Read the ground investigation report before starting excavation on any brownfield site.
Wear PPE specified in the COSHH assessment for the contaminants identified on site.
Carry a personal gas monitor during all excavation work on contaminated ground.
Stockpile contaminated soil on lined areas, separated from clean material.
Follow decontamination procedures when leaving the contaminated work zone.
Wash hands thoroughly before eating, drinking, or smoking on contaminated sites.
Report visual signs of contamination: unusual colours, odours, or oily water.
Dispose of contaminated material through licensed hazardous waste carriers only.
Stop work if you discover buried drums, tanks, or unknown substances.
Ensure first aid provision includes treatment for chemical skin and eye contact.

DON'T excavate on brownfield sites without reviewing the contamination investigation first.
DON'T handle contaminated soil without the PPE specified in the COSHH assessment.
DON'T enter excavations on contaminated sites without a calibrated gas monitor.
DON'T mix contaminated and clean soil — keep them strictly separated at all times.
DON'T leave contaminated areas without passing through the decontamination point.
DON'T eat, drink, or smoke without washing hands after working in contaminated ground.
DON'T ignore unusual smells, soil discolouration, or oily residues during excavation.
DON'T put contaminated waste in normal site skips — it requires licensed disposal.
DON'T disturb unknown buried objects — they may contain hazardous chemicals.
DON'T assume clean-looking soil is safe — only laboratory analysis confirms the status.

See also: Contaminated Land Safety Awareness | Ground Gas Monitoring

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