The release of mercury is a global issue. While the extent of risk from mercury exposure is a matter of debate, it is prudent to refine the measurements of emissions sources and improve society’s understanding of the effects of mercury on human health and the environment.

The United States is the first country to regulate mercury emissions from coal-fired power plants. To the extent that mercury controls are deemed necessary, the federal cap-and-trade program is more economically efficient than the conventional command-and-control regime. Emissions trading at least provides incentives for developing new, cost-effective controls.

Gov. Granholm’s mercury directive will prove to be significantly more costly than the federal program, and not materially more beneficial. Michigan would do better to defer control requirements that exceed the federal standards. This would provide time for development of more effective control technologies under the cap-and-trade program.

In the meantime, Michigan should cooperate with neighboring states and the EPA to better define the risks associated with mercury exposures as well as to refine our understanding of the interplay between mercury emissions, depositions and bioaccumulation.