Regulating Greenhouse Gas Emissions Under the Clean Air Act

This advance notice of proposed rulemaking (ANPR) presents information relevant to, and solicits public comment on, how to respond to the U.S. Supreme Court's decision in Massachusetts v. EPA. In that case, the Supreme Court ruled that the Clean Air Act (CAA or Act) authorizes regulation of greenhouse gases (GHGs) because they meet the definition of air pollutant under the Act. In view of the potential ramifications of a decision to regulate GHGs under the Act, the notice reviews the various CAA provisions that may be applicable to regulate GHGs, examines the issues that regulating GHGs under those provisions may raise, provides information regarding potential regulatory approaches and technologies for reducing GHG emissions, and raises issues relevant to possible legislation and the potential for overlap between legislation and CAA regulation. In addition, the notice describes and solicits comment on petitions the Agency has received to regulate GHG emissions from ships, aircraft and nonroad vehicles such as farm and construction equipment. Finally, the notice discusses several other actions concerning stationary sources for which EPA has received comment regarding the regulation of GHG emissions. The implications of a decision to regulate GHGs under the Act are so far-reaching that a number of other federal agencies have offered critical comments and raised serious questions during interagency review of EPA's ANPR. Rather than attempt to forge a consensus on matters of great complexity, controversy, and active legislative debate, the Administrator has decided to publish the views of other agencies and to seek comment on the full range of issues that they raise. These comments appear in the Supplemental Information, below, followed by the June 17 draft of the ANPR preamble prepared by EPA, to which the comments apply. None of these documents represents a policy decision by the EPA, but all are intended to advance the public debate and to help inform the federal government's decisions regarding climate change.