EPA was planning to issue new rules in December requiring the nation's 1,100 coal- and oil-fired power plants to install equipment to achieve the maximum possible reductions in mercury and nickel emissions. But the plan drew heavy opposition from industry groups and their congressional allies, who argue the new regs would be exceedingly costly and should be eased or delayed beyond the 2007 target date, according to an article inThe Washington Post.

Now, the White House and EPA chief Mike Leavitt are considering rescinding a December 2000 EPA ruling that concluded mercury emissions are a public health threat that requires power plants to meet a "maximum achievable control technology" (MACT) standard to sharply reduce toxic pollutants, according to the article.

The alternative? A mandatory "cap and trade" program, similar to the successful program to combat acid rain that was begun in 1990. It would allow utilities to buy emissions "credits" from cleaner-operating plants to meet an overall industry target.