A powerful blast on a Texas BP oil refinery, the third-largest in the U.S., that killed fourteen people and injured some 100 sent oil prices sharply higher.

The management of the plant that produces 470,000 barrels per day believes the explosion to have been caused by internal failure as terrorism is ruled out.

"We have no reason to believe this was anything caused by an outside agent," said company spokesman Hugh Depland.

The accident sent gasoline prices to an all-time high of $1.6080 a gallon on the New York Mercantile Exchange as the damaged part of the plant was engaged in upgrading gasoline quality. The rest of the refinery is functioning in a normal mode.

The plant covers about 3 percent of U.S. fuel needs, and the disruption in its operations caused by the explosion also boosted retail gasoline prices in the US.

``We know that prices will automatically react to any supply disruption because the entire oil-supply chain is working on a just-in-time basis,’’ said Frederic Lasserre, the head of commodities research at Societe Generale SA in Paris. ``We have very low coverage in terms of stockpiles and this has stopped the selling wave.’’

Even after the accident, the rebounding US currency and the strong increase in oil stockpiles kept the prices under last week’s record of $57.60 a barrel. The U.S. Energy Information Administration (EIA) reported on Wednesday that crude oil stocks added 4.1 million barrels to rise to 309.3 million barrels last week, hitting the peak since July 2002.

May crude oil futures rose $0.63 to $54.44 a barrel.