Under a former petrol filling station the soil and groundwater was found to be contaminated with petroleum hydrocarbons (primarily BTEX). This had been caused by leaks from the station’s underground storage tanks (USTs). The storage tanks have been removed and surrounding soils excavated, however residual contamination persisted in both the soil and groundwater within the source area and the downgradient plume. The regulatory cleanup target is a 50% reduction of the BTEX / HC C5-C10 concentrations in groundwater.