Contractors that operate U.S. government uranium processing plants in Kentucky and Ohio erased hundreds of environmental and safety problems from computer records in 1993 without government approval, according to court documents and other papers obtained by the Louisville Courier-Journal. After a three-year investigation that ended in 1996, the Department of Energy reconstructed the erased items from computer archives and paper records and found that nearly half the problems had not been properly addressed. But the contractors were not fined, nor were the plants shut down at any time, although the DOE did consider closing them for safety reasons. A number of news reports last year publicized widespread health problems and safety violations at the uranium plant in Paducah, Ky.