WASHINGTON, July 22 (Reuters) - The Environmental Protection Agency will as soon as Monday finalize a scientific finding that greenhouse gases from aviation endanger human health, obligating the United States to regulate emissions from commercial aircraft, sources told Reuters.
The EPA's "endangerment finding" requires the agency to implement greenhouse gas emission standards for U.S. aircraft, which accounts for 11 percent of U.S. transportation greenhouse gas emissions and is one of the largest sources of emissions not yet regulated.
EPA Administrator Gina McCarthy is expected to sign the endangerment finding as soon as Monday, two sources familiar with the process told Reuters.
The EPA did not immediately respond on Friday to confirm the timing.
The United States has said it wants to align its aircraft standard with one being developed by the United Nations' International Civil Aviation Organization (ICAO).
McCarthy told Reuters on Tuesday that the agency would finalize the finding "shortly" and that it would "send a signal that the U.S. can integrate (the ICAO standard) in our regulatory structure."
In February, after six years of talks, the ICAO agreed on a global standard aimed at makers of small and large planes, including Boeing Co, Airbus Group SE and Embraer SA that will apply to all new aircraft models launched after 2020.
The standard must still be approved by ICAO's governing council in Montreal in September-October.
The EPA and the Federal Aviation Administration represented the United States in the negotiations, where they pushed for more stringent targets than the European Union.
Estimates for carbon emission reductions from applying the new standards vary widely. The White House said in a fact sheet in February that it would reduce carbon emissions by 650 million tonnes between 2020 and 2040.
Green group Transport and Environment, however, estimated reductions closer to 300 million tonnes over the same period, while the International Council on Clean Transportation (ICCT) projected the standard would only require carbon-dioxide reductions from new aircraft of 4 percent over 12 years.
"The ICAO standard would not reduce that harm identified by the endangerment finding," said Dan Rutherford, ICCT aviation program director. "It's contradictory that EPA would adopt a rule that doesn't do that."
Vera Pardee, senior attorney with the Center for Biological Diversity, which sued the EPA to force it to develop a stringent standard, said the agency has a legal obligation under the federal Clean Air Act to devise a more "meaningful" requirement than ICAO's.
"ICAO standards are not worth talking about because they won't do anything," Pardee said. (Reporting By Valerie Volcovici; Editing by Jonathan Oatis)