Valero Energy UK Ltd have been fined £5 million and ordered to pay costs of £1 million after an explosion killed four workers and seriously injured another at an oil refinery in Pembrokeshire.
On 2 June 2011, five workers were emptying a tank in the Amine Recovery Unit using a vacuum tanker when the explosion occurred. An investigation by the Health and Safety Executive found the explosion was most likely to have been initiated by the ignition of a highly flammable atmosphere within the tank, during what should have been a routine emptying operation in preparation for further cleaning and maintenance.
The investigation also found there had been longstanding failures within the refinery safety management systems and as a result the risks posed by flammable atmospheres within the Amine Recovery Unit were not understood or controlled.
The Court heard that those working for Chevron had failed to know of or appreciate the risk of flammable vapour, which had been building up in the tank over the years. Furthermore, days before the explosion, one Chevron worker carried out a gas test which should have alerted the refinery to the flammable atmosphere, but the results were either mis-communicated or not understood.
Chevron fully accepted responsibility and recognised it did not live up to its own standards. It has implemented changes to avoid another disaster.
When the accident happened, on 2 June 2011, the site was being operated by Chevron and it was in the process of selling the site to Valero Energy UK Ltd.
Under an indemnity arrangement agreed as part of the sale, Chevron is liable for the £5 million fine and the £1 million costs will be met by Valero Energy UK Ltd.
B & A Contracts Ltd, the cleaning contractor, pleaded guilty to breaching Sections 2(1) and 3(1) of the Health and Safety at Work etc Act 1974.They have been fined £120,000 and ordered to pay costs of £40,000.