The oil leak came to light on 19 August last year, when the Environment Agency was told of dead fish on a lake near the depot which had been polluted with oil. Up to 5,000 fish were killed by the pollution.
The source was eventually traced two days later, when staff at the EWS depot discovered a leak in a fuel delivery pipe within a concrete duct. The ducting had been intended to contain any spillage but, according to the Agency, was "totally ineffective" for the task.
EWS also admitted that the material used in the leaking pipe was unsuitable for use with hydrocarbons such as fuel oil.
Appearing before Wantage magistrates on 21 October, EWS pleaded guilty to causing polluting matter to enter the lake, contrary to section 85(1) of the Water Resources Act 1991, and was fined £15,000 with £3,988 in costs.
After the hearing, Agency officer Jeremy Churchill commented: "This serious environmental incident could have been avoided if EWS had adequate checks in place to make sure their fuelling system was fail safe. The case highlights the need for companies to prioritise environmental protection and that business cannot take chances with their environmental responsibilities."
His comments echoed similar sentiments after EWS's previous court appearance in January 2002, when the company was fined £24,000 for three sewage pollution offences in London. The offences occurred after EWS cancelled a maintenance contract at a sewage pumping station at a west London depot. The company claimed in court that management had not been aware that this had been done (ENDS Report 324, p 46 ).
The previous pollution offence at the Didcot depot occurred in 1998 when an interceptor failed, allowing waste engine oil to pass to the site's wastewater treatment system. The oil was then pumped into a rainwater drainage system instead of to sewer because of a faulty connection, and passed into the nearby lake. EWS was fined £8,000 for that incident (ENDS Report 304, p 56 ).