Spill from Fuel Transfer Line in garage
The boiler in the integral garage of this large detached property stopped working. Odours of oil were noted in the rooms of the dwelling adjacent to the garage. Investigation found that a break in the fuel transfer line under the garage floor had caused the boiler to fail and was the source of a loss of oil.
Investigation found soils beneath the garage floor heavily impacted with oil, especially close to the shared wall between the garage and the dwelling. Within the dwelling there is a suspended floor with chipboard joist coverings in some rooms and fitted wood floor in the others. Investigation of the underlying over site concrete and sub soils was undertaken by removal of sections of chipboard and by drilling holes through the wooden floor. Oil impaction was found in over site material and soils below all rooms of the ground floor, especially in soils adjacent to the strip foundations. During the investigation volatile organic compounds in the air were measured and elevated concentrations were detected.
Risks and Remediation
To immediately mitigate the risks to human health caused by the inhalation of oil vapours the occupants of the house had been evacuated. To restore the amenity of the house the oil contaminated concrete and soils under the garage and dwelling were excavated. The footings and foundations were scrubbed with a surfactant and oily water collected and pumped out to a water treatment plant set up at site. Groundwater was encountered during excavation works and this too was pumped out to the waste water treatment plant. The ingress of oily groundwater continued for six months during which time the water treatment works were maintained.
Excavated materials and oil from the water treatment plant were sent for disposal to licensed waste facilities.
Excavations were back filled with clean imported soil and back fill material as appropriate. Reinstatement of the floors and redecoration as necessary were undertaken by a specialist building contractor.
Validation was by field monitoring and submission of soil, groundwater, and air samples for analysis at a UKAS accredited laboratory.Back