The Pentagon isn’t cleaning up thousands of former military sites as quickly as it claims, according to a report released yesterday by the U.S. General Accounting Office, the investigative arm of Congress. In its own review of the $200 million-a-year cleanup program, the Pentagon said that work at more than of half of the thousands of sites contaminated by hazardous waste had been completed. The GAO report found that only a third of the work had been done — and the Pentagon had cherry-picked the easy sites first, leaving the more difficult cleanups for later.