Soil Testing Safe Work Method Statement

A test pit is classified as a confined space when depth exceeds 1.2 metres or when atmospheric hazards are present regardless of depth. The confined space definition under WHS regulations includes any enclosed or partially enclosed space not designed for continuous human occupancy, where hazardous atmospheres may occur. Test pits meet this definition once they become deep enough that a person must enter by descending below natural ground level. Additionally, any pit in contaminated ground, former landfill areas, or organic soils should be treated as confined space due to atmospheric hazard risk even if shallower than 1.2 metres. Entry permits verify that atmospheric testing, ventilation, rescue equipment, and trained personnel are in place before entry. Never enter a test pit without completing permit procedures—multiple fatalities occur annually from confined space entries without proper controls.

PPE selection depends on contaminants identified during site assessment. At minimum, chemical-resistant nitrile gloves and safety glasses are required when handling soil of unknown contamination status. When contamination is suspected or confirmed, upgrade to: disposable Type 5 coveralls with taped wrists and ankles, chemical-resistant gloves appropriate for contaminants present (nitrile for hydrocarbons, neoprene for acids/alkalis), P2 respirators for dust suppression, steel-capped gumboots that can be decontaminated, and face shields if splash risk exists. Sites with significant contamination may require full-face respirators with organic vapour cartridges based on atmospheric monitoring results. If sharps contamination is likely (based on site history), add cut-resistant glove inserts under chemical gloves. All PPE must be removed using proper doffing sequence preventing self-contamination, and contaminated items disposed of as hazardous waste. Workers must be fit-tested for respirators and trained in proper PPE use before conducting contaminated site sampling.

Stop drilling immediately if unexpected contamination is encountered including unusual odours, staining, or foreign materials in drill cuttings. Withdraw drilling equipment and secure the borehole preventing further disturbance. Conduct preliminary assessment including atmospheric monitoring around borehole opening for volatile organic compounds or hazardous gases. Photograph contaminated materials and document findings in field log. Notify site supervisor and project manager immediately—unexpected contamination may indicate broader site issues requiring investigation. Upgrade PPE to appropriate level for contaminants observed, typically including disposable coveralls and upgraded respiratory protection. Collect samples of contaminated material in sealed containers for laboratory analysis to identify contaminants. Implement enhanced decontamination procedures for equipment contacting contaminated materials. Do not proceed with additional drilling until contamination is characterised and appropriate safety controls implemented. Some contamination discoveries trigger regulatory notification requirements—consult environmental authorities if significant contamination encountered. Update site safety plan and contamination management procedures based on findings before resuming work.

Atmospheric testing must measure oxygen content, combustible gas levels, and toxic gases before any entry to test pits deeper than 1.2 metres. Use calibrated multi-gas detector measuring: oxygen (acceptable range 19.5%-23.5%, alarm below 19.5%), combustible gases (acceptable below 10% of lower explosive limit, alarm above 10% LEL), hydrogen sulphide (acceptable below 10ppm, alarm at or above 10ppm), and carbon monoxide (acceptable below 30ppm, alarm at or above 30ppm). Lower detector to bottom of pit and test throughout entire vertical profile—hazardous atmospheres may be stratified with heavier-than-air gases accumulating at lowest points. Test must be conducted immediately before entry as atmospheres change rapidly. If any parameter exceeds acceptable range, do not enter the pit. Implement forced ventilation using blower and re-test before entry. Maintain continuous atmospheric monitoring using detector with audible alarms during occupied period. If any alarm activates during occupation, evacuate immediately using emergency escape procedures. Document all atmospheric readings on confined space entry permit. Re-test atmosphere if pit is left unoccupied for more than 15 minutes—conditions change when ventilation stops.

Samples from contaminated sites require special handling during transport to prevent exposure of transport workers and laboratory staff. Place samples in sealed, labeled containers appropriate for contaminant type—volatile organics require zero-headspace vials with Teflon-lined caps, general contamination uses sealed plastic or glass jars. Double-bag contaminated samples in heavy-duty plastic bags before placing in rigid transport containers. Clearly label outer containers indicating contamination present and any special hazards. Maintain chain of custody documentation throughout transport process. If samples contain dangerous goods concentrations of chemicals, transport must comply with dangerous goods regulations including appropriate packaging, labeling, and transport documentation. Refrigerate samples requiring cold preservation maintaining 4°C temperature using insulated containers with ice packs. Notify receiving laboratory in advance of contaminated sample delivery—some laboratories require special receiving procedures. Never transport samples in passenger compartment of vehicle—use secured cargo area or truck bed. In event of spill or container breakage during transport, implement spill response procedures and notify environmental authorities if significant contamination released. Maintain samples within holding time requirements—volatile organics typically require delivery within 24 hours, other parameters within 7 days of collection.

Stop drilling immediately upon encountering buried drums or waste materials. Withdraw drilling equipment carefully avoiding further disturbance that could rupture containers or release contents. Establish exclusion zone around discovery location preventing access by other workers. Conduct atmospheric monitoring around disturbed area for volatile organic compounds or toxic gases—buried waste may release hazardous vapours. Document discovery photographically and record exact location coordinates. Do not attempt to excavate, move, or sample buried waste without appropriate expert assessment and environmental authority approval. Notify site supervisor, project manager, and client immediately—buried waste discovery has significant implications for project scope and cost. Contact state environmental authority as discovery may trigger contaminated land notification requirements. Some jurisdictions require immediate reporting of buried drums or significant waste finds. Engage environmental consultant specialising in contaminated land to assess discovery and develop safe investigation procedures. Buried waste may require intrusive investigation to characterise contents before safe removal. Expect project delays while appropriate response procedures are developed—worker safety takes precedence over schedule. Secure site preventing unauthorised access to discovery location until proper controls established. Do not resume drilling activities until environmental assessment completed and safe work procedures approved by authorities.