The U.S. Environmental Protection Agency proposed a program for oil and gas companies to make voluntary pledges to cut and track emissions of methane, one component of its wider strategy to target the potent greenhouse gas and combat climate change, the agency said July 23.

The Natural Gas STAR Methane Challenge Program would require companies to make specific reduction pledges and submit data each year, expanding on a program that has been in place since 1993 by offering more transparent tracking and let companies make less specific pledges.

In January, the Obama administration said it wanted to reduce oil and gas industry methane emissions by up to 45 percent from 2012 levels by 2025 that seep out of new drilling equipment and from old and new production facilities through a mix of some regulation and voluntary measures.

The EPA is expected to propose regulations later this summer on methane emissions.

The American Petroleum Institute (API) industry group, which has argued that regulations are unnecessary since methane emissions have fallen even as gas and oil drilling has risen, said it will work with the EPA to improve the proposed program.

"Voluntary programs are the best way to reduce methane emissions from existing sources," said Howard Feldman, regulatory affairs director of API.

Environmental groups were skeptical that the oil and gas industry would take the voluntary measures seriously.

"The industry would like us to believe it will reduce this potent climate pollution out of the goodness of their hearts - we don't buy it," said Meleah Geertsma, an attorney at the Natural Resources Defense Council.

Conrad Schneider, advocacy director for the Clean Air Task Force, warned that EPA cannot rely too much on voluntary measures to curb methane emissions because it has an obligation to regulate them under the federal Clean Air Act.

"The standards must be legally enforceable, something that, by definition, voluntary programs are not," Schneider said.