By Judy Sheahan
April 23, 2007

Commonwealth of Massachusetts, et al. v. Environmental Protection Agency, et al

The Supreme Court ruled 5-4 April 2 that the Environmental Protection Agency (EPA) violated the Clean Air Act by refusing to regulate new vehicle emission standards for pollutants that contribute to global warming. The Conference of Mayors, along with cities, states, and environmental organizations, filed amicus briefs in the case Commonwealth of Massachusetts, et al v. Environmental Protection Agency, et al., supporting the position that EPA should regulate greenhouse gas emissions for vehicles.

The petitioners requested that EPA regulate CO2 and other greenhouse gases using the justification that the Clean Air Act requires the EPA to set emission standards for “any air pollutant” from motor vehicles or motor vehicle engines “which in [its] judgment cause[s], or contribute[s] to air pollution, which may reasonably be anticipated to endanger public health or welfare.” The petitioners argued that greenhouse gas emissions endangered public welfare and therefore EPA should regulate them. EPA’s position was that it did not have statutory authority to regulate greenhouse gas emissions from motor vehicles, and that, even it did, it would not exercise the authority at this time.

Justice John Paul Stevens wrote for the majority saying, “EPA has offered no reasoned explanation for its refusal to decide whether greenhouse gases cause or contribute to climate change and it identifies nothing suggesting that Congress meant to curtail EPA’s power to treat greenhouse gases as air pollutants.”

The ruling could assist efforts to force the federal government to reduce greenhouse gas emissions, as well as empower states to implement new regulations if the federal government does not act.

Conference of Mayors Executive Director Tom Cochran in a press statement said, “We are glad that the EPA has been granted authority under the Clean Air Act to regulate tailpipe emissions of greenhouse gases because they are an important piece towards solving the climate protection puzzle.”

In another court case, Environmental Defense et al. v. Duke Energy Corp, et al, the Supreme Court ruled unanimously supporting an EPA initiative aimed at forcing power plants to install pollution-control equipment.

In this case, Duke Energy made extensive modifications to several coal-fired generating units. Although the changes did not result in any increase in the hourly output of emissions, they did allow Duke Energy’s generators to operate for more hours per day, resulting in an increase in total emissions output per year. The United States sued, claiming that Duke’s changes were “major modifications” as defined by EPA, and that Duke failed to obtain EPA permits for the improvements.

One of the major issues of the case was to determine whether EPA could use its current test under the New Source Review permit program or to allow a more lenient interpretation. EPA requires permits for certain emission “modifications” under the Prevention of Significant Deterioration (PSD) program which focuses on increases in annual emissions and the New Source Performance Standards (NSPS), which has its focus on hourly emissions.

Duke Energy successfully argued in the Fourth Circuit that NSPS and PSD definitions must be the same, and that EPA did not have authority to define PSD “modifications” based on annual emissions. The Supreme Court disagreed and upheld EPA’s view that Duke Energy must have a permit before making extensive modifications that resulted in no increase in the hourly output of emissions, but allowed the generators to run for more hours per day, resulting in more output per year.

Many utilities, which were modifying or planning to modify their facilities, might be impacted by this Supreme Court decision.