The Pentagon, three years after declaring a stepped-up battle against hazardous waste, is making only slow progress in cleaning up thousands of contaminated sites, the House Government Operations subcommittee on environment, energy and natural resources was told. "I don't think we'll see completion of this before the end of this century," said Frank Conahan of the General Accounting Office, the congressional investigative agency. Conahan also said that the GAO is unhappy with the progress of Pentagon programs to better manage hazardous materials in order to prevent creation of new sites that will require cleaning up. Carl Schafer, deputy assistant defense secretary for the environment, testified that the Pentagon has identified 11,800 potential hazardous waste sites, 7,200 of them on property no longer owned or used by the military. He said that remedial work has been completed at 207 sites.