A London company responsible for supplying jet fuel at Heathrow Airport was fined £40,000 last week and ordered to pay the Environment Agency in excess of £14,000 for its costs, after severely polluting groundwater beneath the airport, with at least 139,000 litres of Jet A-1 aviation fuel.

Heathrow Hydrant Operating Company Limited (HHOpCo), of 8 York Road, London SE1 had pleaded guilty at Uxbridge Magistrates’ Court in June this year to causing polluting matter to enter the Taplow Gravels groundwater, contrary to section 85 (1) and (6) of the Water Resources Act 1991. The case had been committed to Isleworth Crown Court for sentence.

The court heard that on 29 November 2007 HHOpCo informed the Environment Agency of a leak in the fuel supply pipeline to aircraft stands at Heathrow’s Terminal One building. The leak was discovered by HHOpCo nine days earlier following an unrelated report from BAA about a report of jet fuel odour in a nearby access tunnel. Without this unrelated report, it is not known how long the leak would have continued to go undetected for. HHOpCo conducted an overnight pressure test on the hydrant system and confirmed the leak, but failed to notify the Environment Agency immediately.

On further investigation HHOpCo staff identified a valve chamber full of approximately 8,000 litres of aviation fuel. Once the valve chamber was emptied, fuel was seen leaking out of one of the attachments on the hydrant. Two bolts on the attachment were so badly corroded that they had caused the leak, which was estimated at the time of discovery to flow at 10 litres of fuel per minute. A later estimate corrected the leak to 7 litres per minute. It is not known how long the leak had been going on for or the total volume of fuel lost.

All bolts and valves on that section of pipeline were subsequently replaced to stop the leak. The section was pressure tested and returned to normal operation the following morning. The chamber in question has now been decommissioned.

HHOpCo attended an interview under caution at the Environment Agency office on the 12 March 2009. The company admitted during the interview that a £7 million automated leak detection system had been malfunctioning at the time and had not detected the leak. This was also indicated in HHOpCo’s investigation report, which revealed that the leak detection system was not working for at least five months prior to the Environment Agency being notified of the incident. The company did not put a manual testing system in place despite knowing that the automated system was not working properly.

It quickly became clear that jet fuel had been leaking for some time. A specialist remediation company sank boreholes to recover fuel and remediate the affected area. As at June 2010 139,391 litres have been recovered and is still being recovered at a rate of 80—100 litres per week.  The cost of remediation to date is approximately £1 million.

Mohammed Jama, the Environment Agency’s lead officer on the case, said:

“Heathrow Hydrant Operating Company’s carelessness has led to the extensive pollution of groundwater. Fortunately, to date, we have not seen any major impact to local rivers but jet fuel in groundwater has the potential to seriously harm the environment and water quality. The fine issued reflects the serious effect that HHOpCo’s failures have had on the Taplow Gravels.

“Once groundwater becomes polluted it is very difficult to clean up. We hope that the fine issued will act as a prompt to HHOpCo and similar companies, reminding them of the importance of compliance and making sure that their actions do not cause harm to or damage the environment. ”

HHOpCo’s contractors have been in charge of remediation and monitoring of the fuel plume and continue to provide updates to the Environment Agency.