Fluor has been working on the cleanup and shutdown of atomic energy plants in Ohio and Washington since the 1990s. In 1992, Fluor won a contract with the United States Energy Department to clean up nuclear waste. By 1996 Hanford was the most contaminated nuclear site in the US and the US Department of Energy was conducting a $50 billion to $60 billion cleanup of the site. Fluor Hanford Inc. replaced Westinghouse Hanford Co. on the project. After a chemical explosion in 1997, 11 workers filed a lawsuit alleging they were denied appropriate medical attention and protective gear. Fluor and the workers disagreed on whether the explosion resulted in any injuries. In 2005 the US Department of Energy fined Fluor for safety violations and that same year a jury awarded $4.7 million in damages to 11 pipe fitters that claimed they were fired after complaining that a valve rated for 1,975 pounds-per-inch was being used where 2,235 were needed.