anacortes refinery fire - Treasury said that the Department of Labor and Industry had been notified.

U.S. Chemical Safety and Hazard Investigation Board is sending six people to investigate the accident, the spokesman Daniel Horowitz described as "very serious."

Horowitz said the board is "extremely concerned about security in this sector", after a number of accidents and safety violations found in refineries by the Occupational Safety and Health Administration.

Activity around the complex had calmed down considerably as dawn approached. Guards were turning to journalists outside the door and there was no apparent trace of the fire he had lit the skies only hours before.

The blast occurred in the unit of gasoline at the refinery. Naphtha is a volatile liquid, flammable products during the refining process, and the unit had undergone maintenance and was in the process of returning to the operation - a "normally dangerous" step of converting heat and pressure, said Wright.

"It's a volatile process," said Wright. "We are diligent about being saved."

San Antonio-based Tesoro Corp. is an independent refiner and marketer of petroleum products. The Anacortes refinery can refine 130,000 bpd, the company said. U.S. Energy Information Administration Web site that ranks as the largest refinery in the nation 59.

Treasury has owned the refinery in Anacortes since 1998. Its main processes of Alaska North Slope crude oil and makes gasoline, diesel and jet fuel, especially Washington and Oregon.

Wright said I can not say yet how long the production will be affected, but the Treasury can probably offset the loss by ramping up production at its other refineries on the West Coast or the purchase of others.