In a rule signed on June 10, 2015, EPA proposed to find that greenhouse gas (GHG) emissions from engines used in certain types of aircraft contribute to air pollution that endangers health and welfare under section 231(a) of the Clean Air Act.  Further, anticipating that the International Civil Aviation Organization (ICAO) will adopt a final CO2emissions standard for aircraft in February 2016, EPA also issued an Advance Notice of Proposed Rulemaking seeking input on the potential use of section 231 to adopt and implement the international aircraft engine CO2 emissions standard domestically.

In the rule, EPA states that it is relying primarily on the scientific and technical evidence in the record supporting the 2009 Endangerment and Cause or Contribute Findings for Greenhouse Gases under section 202(a) (the “2009 finding”), though it also includes subsequent work. It also follows the rationale it previously used with respect to the 2009 finding.  For example, EPA proposes to define the air pollution referred to in section 231 to be the mix of the following six well-mixed GHGs: CO2, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride – the same definition used for the 2009 finding for the purposes of section 202(a).

The rule has been submitted for publication in the Federal Register; the internet version of the rule is available here. Comments will be due within 60 days after publication in theFederal Register. A public hearing will be held in Washington, D.C., on August 11, 2015.