The Massachusetts case was specifically targeted at contamination from engine vehicles, but parallel litigation worried EPA's authority to regulate stationary sources such as power plants and factories. The cases were consolidated, and EPA agreed to their remand for farther consideration in lightweight of the Supreme Court's ruling on Massachusetts v. EPA.
The Court's decision was announced on April 2, 2007, at which issue the Court remanded back to EPA the issue of if carbon emissions constitute human endangerment. In April 2009, the agency resolved the scientific reconsider organised by the ...