Even as Congress prepared to take up a massive spending bill funding the District of Columbia and labor, education, and health and human services this week, House and Senate Republicans were battling over whether to include a provision benefiting the scrap metal industry.

Senate Majority Leader Trent Lott (R-Miss.), with the approval of Senate Minority Leader Thomas A. Daschle (D-S.D.), is trying to attach a provision protecting companies from being held legally responsible for recycling materials from toxic Superfund sites.

Lott tried unsuccessfully to insert the measure into last year's omnibus spending bill. House Speaker J. Dennis Hastert (R-Ill.) and other key Republicans oppose adding it to a must-pass appropriations bill.

Though the proposal enjoys bipartisan congressional support and backing from the administration, it is opposed by a coalition of chemical manufacturers, insurers, automobile companies, small businesses and some environmentalists, who argue that carving out a special exemption for scrap metal dealers unfairly shifts the costs of cleaning up the toxic sites and could jeopardize the passage of broader Superfund liability reform.

"We want to go forward with comprehensive, targeted reform," said Rep. Sherwood L. Boehlert (R-N.Y.), who has authored legislation revamping Superfund laws and is working with Rep. James C. Greenwood (R-Pa.) to produce a compromise bill this week.

But Robin Weiner, executive director of the Institute of Scrap Recycling Industries, argued that Superfund reform has been stalled since 1993 and the industry needed relief now.

It is unclear whether the measure will be incorporated into the final D.C. funding bill: House Republicans said yesterday it was taken out at Hastert's request, but a Lott aide predicted the issue could resurface at any time.