Washington (Platts)--27Dec2012/101 pm EST/1801 GMT

US Environmental Protection Agency Administrator Lisa Jackson, who ushered in significant clean air rules, including the first to control greenhouse gas emissions from industrial sources, Thursday said she is stepping down.

But Jackson, who came to EPA after working for New Jersey Governor Jon Corzine, is leaving before the agency has issued GHG performance standards for existing power plants and refineries, finalized rules governing cooling water used by power plants and rules for disposal of ash from coal-fired generating plants.

The agency also will face having to rewrite an air pollution transport rule to control downwind fossil fuel emissions after a federal court this year threw out its Cross-State Air Pollution Rule.

Under Jackson, EPA made historic gains in curbing GHGs from industry under the Clean Air Act. They include a scientific finding that emissions of CO2 and five other GHGs endanger public health, regulations of tailpipe emissions through efficiency standards and permit regulations for new or modified power plants, refineries and industrial facilities.

The US Court of Appeal for the District of Columbia Circuit on June 26 upheld EPA's GHG action in a 3-0 decision. On December 20, the court rejected petitions by industry for a rehearing of the case.

In the case, Coalition for Responsible Regulation v EPA, the three-judge panel held unanimously that EPA acted within its authority under the Clean Air Act when it issued its 2009 scientific "endangerment" finding.

The panel also agreed that EPA's subsequent GHG emission standards for new vehicles and light trucks were correct and that these regulations then allowed the agency to use the law to regulate stationary sources, such as power plants and refineries.

The court also upheld EPA's "tailoring" rule to regulate only the largest stationary sources for GHGs under the law's "prevention of significant deterioration" or PSD program.

"EPA's interpretation of the governing CAA provisions is unambiguously correct," the three-judge panel said in its opinion for the agency.

Jackson is expected to depart the agency after President Barack Obama's State of the Union address in late January.

"We have made historic progress on all these fronts," Jackson told EPA employees Thursday. "So, I will leave the EPA confident the ship is sailing in the right direction, and ready in my own life for new challenges, time with my family and new opportunities to make a difference."

--Cathy Cash, cathy_cash@platts.com --Edited by Jeff Barber, jeff_barber@platts.com