An oil refinery blast in which four people were killed appears to have been a “tragic industrial accident”, police said.
The blast at Chevron Refinery, Pembroke Dock, south Wales, shook the surrounding area around 6.20pm on Thursday night.
Chief Superintendent Gwyn Thomas of Dyfed Powys police said his officers were informing the relatives of the workers who died.
The fire was caused by an explosion in a 730 cubic metre storage tank, which then caused damage to an adjacent tank.
Chief Supt Thomas added: “A police investigation is now under way, with the Health and Safety Executive, and early indications show that this was a tragic industrial incident. Police officers have secured the scene and colleagues from Mid and West Wales Fire and Rescue are working to make the site safe to enable a multi agency investigation into the cause of the explosion to commence.”
Fire crews from around the area were called to the site of the explosion along with paramedics.
Local people reported hearing the explosion and seeing a plume of black smoke. Marcus Lutwyche, owner of a shop in the village of Angle, told Walesonline: “I ran to the front and saw a huge plume of smoke. It was black and filled the sky. It must have been 50 or so metres wide.”
Earlier this year the sale of the refinery, which is one of the largest in western Europe and employs 1,400 people, was secured. Valero agreed to buy the refinery site for £458M and another £611M for assets including Chevron’s petrol stations in the UK and Ireland.
Chevron later confirmed that the four people who died were contractors and said another worker was receiving treatment in hospital for serious injuries.
Welsh Secretary Cheryl Gillan said: “I am deeply saddened by the news and send my condolences to the families and colleagues of those who have tragically lost their lives. Our thoughts are also with the injured. We’ve been in contact with Chevron and Milford Haven Port Authority and have been asked to be kept fully informed about the investigation into this tragic event. It is essential to understand how this tragedy occurred.”