Four contractors have been killed and another seriously injured in an explosion at Chevron's Pembrokeshire oil refinery in South Wales, UK.
The explosion occurred in a 730m³ storage tank, where maintenance was being carried out at 18.20 BST yesterday.
An police investigation is now being carried out into the incident.
Assistant chief fire officer Chris Davies told BBC news that there was no ongoing risk to the health of members of the public as a result of the explosion and subsequent fire.
"Emergency services were called and responded immediately and remain on the scene," a Chevron spokesperson said in a statement shortly after the incident yesterday. "We are taking appropriate action to respond to the situation. We are still in the process of accounting for all personnel."
The refinery was sold earlier this year to Valero Energy Corporation for $730m. Valero also paid $1bn for assets including Chevron's petrol stations in the UK and Ireland.