By JEFF BARNARD

Associated Press

GRANTS PASS, Ore. (AP) -- Under pressure from some members of Congress, the U.S. Environmental Protection Agency is easing up on regulating global warming pollution from facilities that burn biomass for energy.

The agency said Wednesday it needs more time to figure out whether biomass -- including farm waste, sawmill scraps and forest thinnings -- is really a green fuel.

EPA Administrator Lisa Jackson notified members of Congress who had complained that new rules regulating industrial carbon dioxide emissions would make it hard to develop new biomass energy plants they see as job creators and part of a national green energy strategy.

"I hope you will see the steps described in this letter as following through on my prior commitment to exercise whatever discretion the Clean Air Act affords to avoid discouraging the use of renewable, domestically produced fuel in power plants and factories," she wrote.

The EPA said it would issue a new rule July 1 to exclude biomass from regulations requiring large polluters to reduce their heat-trapping pollution for three years. That regulation went into effect earlier this month.

More than two-dozen members of Congress had asked the agency late last year to reconsider its position on biomass because it can be carbon neutral if emissions are counted as something that would be released anyway when wood rots.

With Republicans in the House gearing up to take on the EPA over greenhouse gas regulations, the biomass decision could sway some votes for legislation aimed at delaying or blocking global warming efforts.

"The EPA was precariously close to enforcing new job-killing regulations, and with the urging of a bipartisan congressional effort, made the right decision in reversing course," Rep. Greg Walden, R-Ore., said in a statement. "I will continue to watch the EPA carefully to ensure that the new economic opportunities that woody biomass offers for rural Oregon has the opportunity to move forward."

Developing biomass energy is key to one of Oregon Gov. John Kitzhaber's lead initiatives: putting people back to work thinning forests at high danger of wildfire. To pay for those jobs, he needs new plants built around the state that will buy the trees and branches thinned out of the forests.

Nationwide, biomass plants generate less than 1 percent of the grid, according to the U.S. Department of Energy.

Agriculture Sec. Tom Vilsack said in a statement that markets for the trees and branches left after thinning would help the national forests reduce the threat of wildfire.

Bill Carlson, of the USA Biomass Power Producers Alliance, said the decision was encouraging to businesses that have been uncertain over investing in new biomass plants. It would give time to settle scientific debate over whether biomass helps combat global warming or not, he said.

Timberland owners also lobbied hard for recognition of biomass as a green fuel, especially since lumber prices have fallen with the housing bust.

"It is now critical that we work together in the coming months on deliberate steps to support biomass energy production," Dave Tenny, president of the National Alliance of Forest Owners, said in a statement.

Meg Sheehan of the Stop Spewing Carbon Campaign in Cambridge, Mass., said the EPA was ignoring evidence that biomass is dirtier than coal and carbon from any source contributes to greenhouse gasses.

"I find it very disturbing that the Obama administration and Secretary Vilsack are punting on making this decision until after the next presidential election," she said. "I think it shows extreme disregard for the health of the American people."

Ann Weeks, senior counsel for the Clean Air Task Force, a Boston environmental group, welcomed a closer look at the science.

"All biomass does not provide immediate greenhouse gas mitigation, and in fact some may have greater climate impacts than fossil fuels," she said in a statement.

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Associated Press writer Dina Cappiello in Washington, D.C., contributed to this report.

Copyright 2011 The Associated Press.