Although the main blaze was extinguished yesterday, firefighters were still burning off pockets of fuel trapped in the maze of blackened and twisted pipework at the plant, near Pembroke, Dyfed.
Technical experts investigating the cause are expected to be allowed into the affected section of the 550-acre site today. The theory that a lightning strike several hours before the explosion acted as a catalyst not been ruled out.
Ronnie King, Chief Fire Officer for Dyfed, said last evening: 'It is still a volatile situation because of the nature of the product. We first have to burn off any remaining fuel and chemicals left in the area to prevent any further flare-ups.'
A small army of maintenance personnel spent yesterday making safe danger spots, and squads with brushes and shovels swept huge quantities of glass from the refinery's sprawling car park.
Two of the 26 units which together refine about 3 million gallons of petrol a day were wrecked in the explosion and fires. Texaco is still assessing how long the refinery is likely to be out of action but petrol prices will not be affected.
Derek Lloyd, the company's public affairs manager, said the refinery's 150 tanks had up to 350 million gallons of petrol in storage. Although 26 Texaco staff were taken to the medical centre, only three needed treatment for minor cuts and bruises. But the toll would have been far higher had the blast not happened on a Sunday.
A special team has been set up to help householders and shopkeepers in the Pembroke and Milford Haven area, who had windows and doors shattered by the explosion.
Yesterday, glaziers from as far afield as Swansea, 50 miles to the east, were replacing windows in Charles Street, Milford Haven, two miles across the water from the plant. The Gateway store, Boots, a building society and a toy shop were among the businesses which had their plate glass shattered.
The cost of replacing glass in homes, shops and cars, and repairing ceilings and roofs in the area, would be borne by Texaco, the company has promised.