Environmental Protection Agency Administrator Lisa Jackson says that her policies aren’t the cause of stiff headwinds facing the coal industry.

“[I]n my opinion the problem for coal right now is entirely economic,” Jackson said in an interview published Monday.

{mosads}The comments come as the Senate prepares to vote as soon as this week on Sen. James Inhofe’s (R-Okla.) proposal to overturn EPA rules that require cuts in mercury and other pollutants from coal-fired power plants.

Coal remains the nation’s largest source of electric power, but its share is declining.

Industry officials and many Republicans say a pair of rules forcing cuts in toxic and smog-forming pollutants from existing coal plants and separate regulations setting carbon dioxide standards for new plants pose an existential threat to coal.

But while EPA rules create new costs, Jackson argues that low natural-gas prices and booming gas production are coal’s real challenge.

“The natural gas that this country has and is continuing to develop is cheaper right now on average. And so people who are making investment decisions are not unmindful of that — how could you expect them to be? It just happens that at the same time, these rules are coming in place that make it clear that you cannot continue to operate a 30-, 40- or 50-year-old plant and not control the pollution that comes with it,” Jackson told the online environmental magazine Grist that was also run by the Guardian, a British paper.

Coal once provided over 50 percent of U.S. electric power but its share has been declining, hastened along by natural-gas prices that have recently been at 10-year-lows.

The numbers move around for various reasons, but in March coal’s share fell to 34 percent, according to the federal Energy Information Administration, which is the lowest level since at least 1973.

Jackson, in the interview, also has some tough words for the press, and says that Washington, D.C. isn’t a hospitable place for scientific information.

“Inside the Washington Beltway I’m not sure whether facts always matter, and that’s a sad thing for our country. But oftentimes EPA’s work is peer-reviewed and then peer-reviewed again — and yet it will be challenged by some report that hasn’t been peer-reviewed at all,” she said.

This post was updated at 11:06 a.m. on June 14