The plant is one of the largest in western Europe and refines 220,000 barrels of petroleum per day, with the employment of 1,400 workers. It was inaugurated in 1964 and in 1982 a fluid catalytic cracking unit came on-stream. Other features are units for HF Alkylation, catalytic reforming and three for hydrotreatments. Acidic crude oils e.g. Captain and Doba crude can be handled at the Pembroke refinery.
The refinery was initially owned by the Regent Oil Company, which marketed crude oil from Trinidad, but in 1956 became owned by Texaco. The refinery passed into the hands of the Chevron Corporation when they took-over Texaco. Earlier this year it was confirmed that Valero Energy had agreed to buy the refinery for $730m (£458m) and another $1bn (£611m) for various assets including Chevron's UK and Ireland-based petrol stations.
Ten fire-engines were sent to the incident by the Mid and West Wales Fire and Rescue Service who brought it under control within an hour and a half. Since the wind was blowing offshore, away from residential areas, any noxious material resulting from the blast and fire was carried out to sea.