On May 13, 2014, a three-judge panel from the U.S. Court of Appeals for the District of Columbia Circuit ruled in WildEarth Guardians v. EPA, et al. Previously, WildEarth Guardians filed a rulemaking petition seeking an endangerment finding by EPA that would trigger regulation of coal mines under Section 111 the Clean Air Act. EPA denied the rulemaking petition citing agency discretion and budgetary restrictions, and the environmental group appealed. The D.C. Circuit ruled EPA has reasonable discretion to carry out its delegated responsibilities, which includes determining the timing and relative priority of its regulatory agenda.

In June 2010, Earthjustice, acting on behalf of WildEarth Guardians, the Sierra Club, and other environmental groups (Petitioners), sent a petition to EPA invoking Section 111 of the Clean Air Act. Section 111 provides that EPA must publish and periodically revise “a list of categories of stationary sources [and shall include a category on the list] if in [the Administrator’s] judgment it causes, or contributes significantly to, air pollution which may reasonably be anticipated to endanger public health or welfare.” Section 111 also requires EPA to propose performance standards for new sources within a newly established stationary source category within one year of listing.

The Petitioners urged EPA to make a finding that air emissions from coal mines endanger public health and welfare. Specifically, the Petitioners sought to include surface, underground, and abandoned coal mines within a new source category primarily due to their methane emissions. The petitioners asserted that methane is the second-most emitted greenhouse gas (GHG), and its heat trapping capability is 20 times stronger than carbon dioxide. If EPA had agreed and made an endangerment finding, coal mines would be listed as a new stationary source category pursuant to Clean Air Act Section 111. EPA would then establish performance standards for new and modified sources within the new stationary source category for coal mines and establish performance standards to address methane emissions from existing sources.

On April 30, 2013, then Acting EPA Administrator Bob Perciasepe denied the petition. In its denial, EPA declined to address the merits of the endangerment petition. As a result of numerous budget cuts, EPA argued that it must have discretion to prioritize its regulatory agenda. EPA further responded that its limited resources are best spent addressing more prominent contributors to GHG emissions such as transportation and electricity systems. On July 8, 2013, WildEarth Guardians filed a lawsuit in D.C. Circuit challenging EPA’s refusal to make an endangerment finding.

In the D.C. Circuit’s May 13 ruling, the court explained that EPA may exercise reasonable discretion in determining when to add a new source to the list of regulated air pollutants. Further, as part of this discretion, EPA may prioritize sources that are the most significant threats to public health. The court relied, in part, on EPA’s rulemaking actions to regulate GHG emissions from electric generating sectors, which account for 60 percent of total GHG emissions. These actions justified EPA’s current reluctance to regulate GHG emissions from coal mines, which account for 1 percent of GHG emissions. The D.C. Circuit’s decision supports EPA’s discretion to prioritize its rulemaking actions in light of current budgetary restraints. Importantly, EPA’s denial of the rulemaking petition still leaves the door open for regulation of GHG emissions from coal mines at a later date.