Air Pollution

The U.S. Supreme Court announced on Feb. 23 that it would not consider a case seeking to revive a Bush Administration regulation controlling mercury emissions from power plants.

The high court let stand a federal appeals court's 2008 decision overturning the regulation (C&EN, Feb. 18, 2008, page 6).

The rule relies on a cap-and-trade system to control mercury emissions. Environmental activists and more than a dozen states worried that this strategy would lead to high concentrations of the neurotoxic metal downwind of power plants that choose to buy pollution allowances from cleaner facilities instead of controlling their own emissions.

The regulation was the first in the world to control mercury pollution from power plants; it attracted controversy since the Bush EPA issued it in 2005.

A federal appeals court overturned the regulation in February 2008 because of a move EPA made to set up the cap-and-trade program. The agency removed utilities from a list of sources whose emissions must be tightly controlled under the Clean Air Act, an action the appeals court said was unlawful.

A coalition of coal-fired utilities seeking reinstatement of the cap-and-trade rule last year had asked the Supreme Court to review the appeals court decision.

Earlier this month, the Obama Administration announced that EPA plans to draft a new regulation that would specify the type of mercury control equipment that each power plant would have to install (C&EN, Feb. 16, page 34).