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 tells the Guardian in an interview published Monday.

The comments come as the Senate prepares to

vote as soon as this week on Sen. James Inhofe's (R-Okla.) proposal to overturn EPArules

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.