The Sierra Club (search) alleges in a lawsuit that the Bush administration (search) changed a rule so oil and gas producers could more easily drill under national parks (search) from outside their boundaries.

The environmental group alleges in the suit filed Wednesday that the change affects 14 national parks that have privately owned minerals beneath them.

The suit asks the U.S. District Court in the District of Columbia for an immediate injunction to reverse the change it alleges, which it said was done without public input, and also to drop drilling.

The National Park Service denied the allegation.

"That is so untrue. There has been no change from the Bush administration, from the Clinton administration," said Carol McCoy, a Denver-based National Parks Service spokeswoman. "Nothing has been done outside the public process."

Oil and gas producers can drill at an angle to reach privately owned minerals from private land adjacent to a park.

Under a 1979 rule, the National Park Service must study such drilling plans and their possible impacts to the park or adjacent land. Also, the drilling company was required to submit environmental impact analyses.

But the Sierra Club alleges that since late 2001 the National Park Service has been allowing directional drilling without such impact analyses. The environmental studies required of drilling companies also have been reduced, the group says.

The Sierra Club says the drilling or its equipment could cause problems with air and water pollution or noise problems. It also says trucks traveling on roads near the park could be an issue. The group also is concerned about what damage any accidents, such as well blowouts, might cause.