During the 2000 budget year, the federal government awarded more than $855 million worth of contracts to companies that had violated at least one federal law in the previous three years, the General Accounting Office reported yesterday. In all, 39 companies winning contracts of $100,000 or more were guilty of violating federal environmental, labor, employment, or antitrust laws — despite the fact that contracting rules prohibit companies from receiving federal contracts without “a satisfactory record of integrity and business ethics.” The Clinton administration tightened the rule requiring companies bidding on federal contracts to certify compliance with federal laws, but the stricter rule was revoked after President Bush took office. Although the report did not identify the offending companies by name, the lawbreakers included a waste-disposal company that illegally dumped nearly 23 million gallons of waste and falsified documents to avoid paying higher dumping fees; a safety equipment manufacturer that illegally stored hazardous waste; and a poultry company that illegally discharged 11 million gallons of polluted storm water into a federal wildlife refuge.