By Valerie Volcovici

WASHINGTON, June 10 (Reuters) - The U.S. Environmental Protection Agency on Wednesday said greenhouse gases from aircraft endanger human health, taking the first step toward regulating emissions from the domestic aviation industry.

The EPA's endangerment finding kicks off a process to regulate greenhouse gas emissions from the aviation industry, the latest sector to be regulated under the Clean Air Act after cars, trucks and large stationary sources like power plants.

The finding allows the EPA to implement domestically a global carbon dioxide emissions standard being developed by the International Civil Aviation Organization (ICAO).

The U.N. agency is due to release its CO2 standard for comment in February 2016 and adopt it later that year.

The EPA had been under pressure from environmental groups who first petitioned it to regulate aircraft emissions under the Clean Air Act in 2007 and sued it in 2010. A federal court ruled in favor of those green groups in 2012.

Aviation accounted for 11 percent of energy-related carbon dioxide emissions from the transportation sector in 2010 in the United States, according to the International Council on Clean Transportation.

The airline industry has favored a global standard over individual national standards since airlines operate all over the world and want to avoid a patchwork of rules and measures, such as taxes, charges and emissions trading programs.

"If you're a big airline and you're flying to 100 countries a day, then complying with all those different regimes is an administrative nightmare," said Paul Steele, senior vice president at the International Air Transport Association, the main global airline industry group.

But some environmental groups are concerned that the standard being discussed at ICAO will do little to change the status quo since it would only apply to new and newly designed aircraft that will not be in operation for several years.

"The stringency being discussed at ICAO is such that existing aircraft are already meeting the standard they are weighing," said Sarah Burt, an attorney at Earthjustice, one of several groups that sued the EPA to regulate aircraft. (Reporting By Valerie Volcovici; additional reporting by Victoria Bryan in Miami; Editing by Susan Heavey and Doina Chiacu)