Energy company fined for south Uists oil spill

Scottish Hydro Electric Power Distribution Plc has been fined £20,000 at Lochmaddy Sheriff Court for causing the pollution of Loch Carnan following a spill of red diesel in November last year.

The energy company was fined after pleading guilty to carrying on an activity liable to cause pollution of the water environment after approximately 45,000 litres of red diesel gas/fuel leaked from a corrosion hole in a fixed oil tank, which bypassed the secondary containment system and entered groundwater and Loch Carnan. The incident, which had a devastating impact on the water environment, was reported to the Procurator Fiscal by the Scottish Environment Protection Agency (SEPA).

SEPA was alerted to the problem on Monday 17 November 2008 when the company contacted SEPA’s 24 hour communications centre. On attending the scene SEPA officers observed areas of oil displaying bright bands of colour extending two meters into the sea from the shoreline. Booms had been deployed at both entrances of the bay directly below the power station.

From their investigations the officers concluded that the oil had entered the water environment through a direct discharge from a piped outfall on the shoreline, as a result of surface runoff, and also by seepage through the ground.

An area immediately to the north of the bunded tanks had been excavated and this excavated area was saturated with oil. Oil had entered broken pipe work leading from the oil interceptor to the shoreline. The ground between the Loch Carnan Power Station and the shoreline was saturated with oil, appearing as red pools in the grass at the shoreline. Absorbent materials had been deployed, however there were also accumulations of oil on the shoreline which appeared red in colour. Oil was also observed entering a stream running adjacent to the site boundary, beginning downhill of the area between bulk oil storage tanks one and two. SEPA officers were not able to gauge the full impact of the oil at this stage due to the poor light < conditions, however it was clear that the spill was significant.

On their return the next morning the full scale of the spill became apparent. Significant amounts of oil were observed on the ground, in excavated areas, in the nearby stream and on the shoreline. In the stream adjacent to the site, a brightly coloured sheen of oil extended approximately 15 meters to the shoreline, where dead worms and dead crabs were observed. Areas of the sea directly below the power station were very red in colour. That afternoon officers visited a nearby fish farm, where they witnessed oil in the cages.

Inspections by the company established that the diesel had leaked from storage tank one, due to a corrosion hole in the base. As the bund was permeable, this allowed fuel to enter the water environment in three ways; groundwater via the subsoil; and Loch Carnan via a surface water tributary and the outfall pipe leading from the oil interceptor drain.

Hazel MacLeod, SEPA’s investigating officer, said:

“Diesel and fuel oil can have a severe polluting effect on a watercourse. The oil forms a film over the water and therefore prevents oxygen exchange from occurring resulting in low levels of oxygen which can lead to the death of fish and invertebrates. The death of invertebrates also has an impact on fish life.

“The discharge of oil in this instance was not and would not be licensed by SEPA. It had an impact on the use of the water for recreation, not only through the direct pollution and damage to amenity caused by the oil itself, but also through the associated construction of a breakwater to assist in the oil clean up exercise.

“The hole in the storage tank was small, and would not have been easily identified. However, the bund surrounding the oil tanks was not fit for purpose as it had a permeable base.  Had a secondary containment system that was fit for purpose been provided at the site, oil leaking from the tank would have been contained within the bund, and would not have been able to escape the site and enter the water environment. Scottish Hydro Electric Power Distribution Plc is aware of the requirements of the oil storage regulations but despite this, during a recent upgrade of the bunding at this site, they neglected to provide bunding to the area directly underneath the oil storage tanks.”

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