The United States Environmental Protection Agency (“EPA”) has taken the initial steps toward regulating emissions from certain types of aircraft engines. As anticipated, on June 10, 2015, EPA announced that it was “proposing to find that greenhouse gas (GHG) emissions from certain classes of engines used in aircraft contribute to the air pollution that causes climate change and endangers public health and welfare under section 231(a) of the Clean Air Act. . . .” EPA Takes First Steps to Address GHG Emissions from Aircraft Engines, June 2015

This finding, once finalized, will allow EPA to conduct a subsequent rulemaking process to adopt a corresponding aircraft emissions standard under Clean Air Act section 231. However, rather than adopting its own standard, EPA is contemplating adopting and implementing the international aircraft-engine COemissions standard currently under development by the International Civil Aviation Organization (“ICAO”). The ICAO is expected to adopt its standard in 2016, with implementation occurring several years after adoption. It is not settled at this point what the ICAO standard will require, or whether it will apply only to new engines or to both new engines and engines already in service.

EPA’s aircraft-engine endangerment finding, which is in response to litigation filed by environmental groups in 2007 and additional litigation threatened in 2014, would be similar to the endangerment finding EPA made with respect to motor vehicles in 2009. EPA specifically proposes to find that GHG concentrations in the atmosphere endanger the public health and welfare of current and future generations within the meaning of section 231(a) of the Clean Air Act, and that GHG emissions from certain aircraft engine classes are contributing to the mix of GHGs in the atmosphere. That mix of GHGs include the same six GHGs identified in the 2009 motor vehicle endangerment finding: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride.

The proposed finding would apply to emissions from engines used in subsonic jets with a maximum takeoff mass (“MTOM”) greater than 5,700 kilograms, and subsonic propeller-driven (e.g., turboprop) aircraft with a MTOM greater than 8,618 kilograms. This covers most small jets up to the largest commercial airliners’ jets, and the larger turboprop engines like those in the ATR 72 and the Bombardier Q400 regional airliners.

A copy of EPA’s advance notice of proposed rulemaking can be found here.