Chevron has launched its own investigation into the explosion at its Pembroke refinery in which four men died. The inquiry will run in tandem with the Health and Safety Executive’s investigation.

One storage tank is out of action and another is damaged but otherwise the plant remains fully operational and the company does not anticipate any significant disruptions to supply. Non-essential work has been suspended today.

Greg Hanggi, refinery general manager, said: “Chevron is hugely saddened by the death of four of its contractor colleagues in the incident yesterday evening and our thoughts go out to their families at this very difficult time. One contractor colleague remains in hospital where he is still receiving treatment.

“Pembroke Refinery is a very close family and this tragedy has been a great shock to everyone. The welfare of our employees is our key priority and we are providing counselling support to all our staff and their families.

“We will 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.

“I would like to thank all the on-site responders and emergency service personnel for the dedication and professionalism they showed throughout this incident.”