London, June 3: Authorities are investigating an explosion which killed four workers and injured another at an oil refinery in southwestern Wales.
Fire officials said Friday morning that the fire at the Chevron refinery in Pembroke was extinguished quickly, and that they were confident there was no threat to public health.
"A police investigation is now under way with the Health and Safety Executive, and early indications show that this was a tragic industrial incident," said Chief Superintendent Gwyn Thomas of Dyfed Powys Police.
"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."
The explosion was reported just after 6 p.m. (1700 GMT) Thursday at the refinery, which specializes in processing heavy, lower-quality crude oils. The blast sent thick black smoke pouring from a storage tank which was undergoing maintenance. A nearby tank was also damaged.
Chevron said four contract workers were killed. Their names were not immediately released.
Greg Hanggi, refinery general manager, pledged to "take every step possible to determine the series of events that led to this tragic incident and ensure that any lessons learnt from it will be integrated into the business and shared with our industry partners."
In March, Chevron announced it was selling the Pembroke refinery along with other marketing and logistics assets throughout the U.K. and Ireland to Valero Energy Corp. of San Antonio, Texas for $1.73 billion. The refinery employs 1,400 people. AP