In April 2010 the five companies accused of causing the explosion faced a criminal prosecution brought by the Health and Safety Executive and the Environment Agency. Two defendants, Total UK and British Pipeline Agency Limited, had already pleaded guilty to offences under the Health and Safety at Work Act. The remaining three, Hertfordshire Oil Storage Ltd, TAV Engineering Ltd and Motherwell Control Systems were found guilty in June 2010. TAV Engineering Ltd and Motherwell Control Systems were found guilty of failing to protect their employees. Hertfordshire Oil Storage Ltd was found guilty of failing to prevent major accidents and limit their effects and then pleaded guilty to causing pollution to enter controlled waters underlying the vicinity around the site, contrary to the Water Resources Act.