This study investigated the interactions between cable insulating oil and the soil microflora and macrofauna in freshly-spiked and in aged soils in the laboratory. Studies were carried out at two levels: (i) The impact of varying concentrations (1-10% w/w) of the non-aqueous phase liquid (NAPL) on soil microbial respiration using [1-C-14]glucose and (ii) The impact of the NAPL on the survival of earthworms (Lumbricus terrestris) in soil. In terms of soil-microbial respiration, [1-C-14]glucose mineralization was found to be enhanced by 32% over a range of oil-soil concentrations and contact times. In freshly spiked soils, all of the earthworms died after 14 d. However, in the 300 d aged soils, survival was significantly increased at lower concentrations of NAPL. If low concentrations (less than or equal to 1%) of NAPL are released to the soil environment from underground power cables it is postulated that a shift in the balance of the soil microflora from autochthonous to zymogenous microflora may occur. Additionally, the bioavailability of the NAPL to the soil macrofauna decreased with increased soil NAPL contact time.}