A Fight Over Cross-State Pollution

New York Times
13 December 2013

The Environmental Protection Agency is charged by the Clean Air Act with setting air-quality standards and issuing regulations to limit pollutants like life-threatening particulate matter and ozone. Because bad air often travels far from its source — 93 percent of the air pollution in New Haven, Conn., for example, comes from other states — the act’s “good neighbor” policy requires that every state work to assure that the pollution from its power plants does not “contribute significantly” to the pollution in other states. If a state has no plan or an inadequate one, the E.P.A. can impose its own.

That is what the agency did in 2011 when it passed a rule imposing new pollution-control requirements on states deemed responsible for contributing to pollution in downwind states. In part because there was no way to determine each upwind state’s proportional responsibility for the pollution in downwind states, the E.P.A. came up with a cost-based formula that essentially ordered each state that exceeded a certain emissions threshold to reduce those emissions by the cheapest means possible.

Industry groups and 14 affected states, mostly in the Midwest and Southeast, challenged the rule — arguing, among other things, that it unfairly requires some states to reduce pollution by more than their actual contribution to the downwind problem. The United States Court of Appeals for the District of Columbia Circuit agreed and struck down the rule.

On Tuesday, the Supreme Court heard oral arguments in the case, which at heart is about the scope of the E.P.A.’s power to protect the nation’s air quality in the face of imprecise information. Several justices appeared sympathetic to the agency’s view that because it is technologically impossible to quantify each state’s responsibility, a cost-based regulation was the most appropriate way to improve air quality for everyone. That is clearly right, even if the states don’t like to hear it.

On the same day that the Supreme Court was considering these issues, the federal appeals court that invalidated the E.P.A.’s rule was hearing arguments in another air-quality case, this time a challenge to the agency’s new standards for mercury and other toxic air pollutants. In both cases, the courts should defer to the expertise of the agency and empower it to tackle complex environmental problems by considering both cost and human health.