From Now with Bill Moyers 6/25/04
"The thing is, for a known neurotoxin like mercury, the Clean Air Act has a specific set of rules: emissions need to be reduced at each and every power plant by the best available technology. But the EPA's preferred plan lumps mercury in with plain old pollutants where more lenient rules apply."
"BRANCACCIO: Jeffrey Holmstead says the EPA's preferred plan is more cost effective and efficient. It's called cap-and-trade.
Instead of forcing each and every coal-fired plant to cut mercury emissions, cap-and-trade lets power plants that do a good job controlling mercury sell pollution credits to plants that do a bad job of it, even though it's a toxic element and not run-of-the-mill pollution."
http://www.pbs.org/now/transcript/transcript326_full.html