Site investigation involves drilling boreholes, excavating trial pits, and collecting soil and groundwater samples to characterise ground conditions and contamination. This work often takes place on brownfield land with unknown hazards including buried asbestos, chemical contamination, unexploded ordnance, and ground gases. Workers carrying out site investigation must be trained in contaminated land procedures and equipped with appropriate PPE and gas detection equipment.
Key Hazards
Exposure to unknown chemical contamination in soil and groundwater samples
Ground gas release during drilling or trial pit excavation on former industrial sites
Contact with buried asbestos fibres when excavating made ground and fill material
Unexpected discovery of unexploded ordnance on former military or industrial land
Control Measures
Review all available desk study information before mobilising to the site investigation location.
Carry a calibrated multi-gas detector and monitor continuously during all drilling and excavation.
Wear the PPE specified in the COSHH assessment including gloves, coveralls, and RPE as required.
Locate and mark all buried services before drilling or excavating any borehole or trial pit.
Seal and label all soil and water samples correctly for laboratory analysis and chain of custody.
Decontaminate all drilling equipment, tools, and PPE before leaving the site to prevent cross-contamination.
Brief the investigation team on the suspected contamination types and emergency procedures.
Ensure welfare facilities with hot water and washing products are available on site for decontamination.
Stop work and report immediately if unexpected odours, discolouration, or suspect materials are found.
Remember
Site investigation on brownfield land may encounter contamination not identified in the desk study.
Gas detection is essential during all drilling and excavation on sites with contamination potential.
Unexpected asbestos in made ground is common on brownfield sites and requires immediate work stoppage.
All samples must be sealed, labelled, and handled in accordance with chain of custody procedures.
Decontamination of equipment and PPE prevents spreading contamination between locations.
If you encounter anything unexpected — unusual smells, colours, or materials — stop and report immediately.
Applicable Legislation: COSHH Regulations 2002 · CDM Regulations 2015 · BS 10175 (Investigation of Contaminated Sites) · Health and Safety at Work etc. Act 1974