The BP oil refinery in Texas City (search), site of Wednesday's fatal explosion and fire, is a major supplier of petroleum products including gasoline. Safety regulators have cited the company for two accidents in the past year, including one that killed two workers.

The refinery produces 30 percent of BP's North American (search) supply of petroleum products, and 3 percent of the U.S. supply. It processes about 430,000 barrels of crude oil.

About 1,800 people work at the plant, which contains 30 refining units spread over 1,200 acres.

The Occupational Safety and Health Administration (search) has issued several citations to BP concerning the two other accidents at the plant in the past year.

— Two workers died and another was seriously injured after they were flooded with superheated water in September. OSHA said employees tried to remove a valve from a high-pressure hot water line without first relieving pressure in the line.

The agency proposed a $109,500 fine, saying that BP failed to maintain equipment or provide protective gear. BP is contesting the charges, according to an OSHA spokeswoman.

— OSHA also cited BP after a furnace pipe ruptured and released flammable vapors that started a fire in March 2004. "BP Amoco had the experience and knowledge to prevent this accident, yet allowed hazardous conditions to develop," OSHA's regional director, Charles Williams, said at the time.

The agency proposed fines of $63,000. Some charges were dropped, and the company settled by paying $13,000 and fixing some problems, according to OSHA.