Oil refinery blast kills four

Four people have died in an explosion in an oil refinery in Wales, sparking a safety inquiry.

An investigation into the blast at Chevron refinery in Pembroke is now underway but early reports suggest that the explosion occurred in a storage tank as maintenance was being carried out, killing four workers.

A fifth contractor has suffered serious burns and was taken to hospital for treatment.

"Officers are now in the processes of informing the next of kin and will support the families throughout this difficult time. Our thoughts are now with the family, friends and colleagues of the deceased," said chief superintendent Gwyn Thomas, of Dyfed Powys Police.

He described the blast at the oil refinery as a "tragic industrial incident".

Witnesses at the scene described a huge plume of thick black smoke which filled the sky and locals expressed their concern for those killed and injured in the blast.