Oil spill from service station fuel pump

The team were contacted about an oil spillage at a busy service station in County Louth.

The spillage originated from an above-ground valve within a pump, and a significant amount of oil had gone into the ground. The spillage impacted soils beneath the dispensing pumps, around the underground storage tanks, and interceptor surface water drainage pipework.

The contamination also migrated through the underground drainage network to a nearby watercourse. A 1.5km section of this watercourse was confirmed to have been impacted by oil contamination, resulting in the involvement of the Local Authority.

As a matter of urgency, we implemented emergency containment works, which consisted of the following:

• Installation of containment measures and absorbent materials within the watercourse
• Removal of impacted surface water from within the watercourse via surface skimming and vacuum tinkering. This prevented migration of oil further downstream to sensitive areas where drinking water abstraction points were located
• Installation of an oil-water interceptor at the site to abstract water from the impacted surface water drainage pipe
• Up to 17 exploratory boreholes were installed across the site to delineate the plume of contamination. The associated investigation findings then allowed us to understand the source-pathway-receptor linkages and environmental risks, so that an appropriate remedial programme of works could be devised and implemented

The most significant risk we identified was to the watercourse, flora/fauna, and third-party lands as a result of neat oil and contaminated water run-off entering the watercourse via underground drainage.

There was also the potential for risks to human health due to the presence of drinking water extraction points downstream of the impacted section of watercourse.

A comprehensive remedial programme of works was completed to mitigate the risks associated with the oil loss at the site. These works were completed whilst ensuring the forecourt remained operational through the implementation of appropriate safety measures.

The remedial works consisted of the following:

• The removal and disposal of contaminated soils (totalling 135 tonnes) from the areas surrounding the dispensing pumps, underground fuel storage tanks and on-site interceptors
• All disturbed and excavated areas were reinstated to a very high standard
• We also undertook a water quality monitoring programme to assess the impact to the watercourse and receptors

The emergency response phase and subsequent extensive remedial phases of works were successful in minimising the impact to the environment and identified sensitive areas.

The effective management of the works and frequent communications with the Local Authority also prevented prosecution of the service station site operator.