Federal rules governing overtime, which went into effect just a few weeks ago, are facing another challenge: the U.S. House of Representatives has moved to block the Department of Labor from enforcing them. The central point at issue is the number of workers who will lose overtime eligibility. Opponents claim as many as 6 million people could be negatively affected, but the Bush administration says that while about 100,000 workers would lose overtime eligibility, some 1.3 million low-wage workers would gain it.