Another energy company has agreed to drop its oil and gas leases near Glacier National Park.

In a joint announcement, U.S. Sens. Jon Tester and Max Baucus of Montana say BP PLC has agreed to relinquish its holdings in a bit more than 1,800 acres on the northwestern side of the park. Almost 400 of those acres are on the doorstep to the park's West Glacier entrance, the two said.

That brings to nearly 200,000 acres worth of leases that energy development companies have agreed to let go in the North Fork of the Flathead River watershed. And most of that acreage has been relinquished at no cost to taxpayers, according to the two senators.

The two Democrats did not, however, explain how they convinced BP or the other energy companies to relinquish the leases without compensation. Calls Tuesday afternoon to BP and the senators' offices were not immediately returned.

In recent years there have been concerns among environmental and conservation organizations that energy development in the Canadian Flathead, the area that embraces the headwaters of the Flathead River and which lies due north of Glacier and due west of Waterton Lakes National Park in Canada, could adversely impact the parks and the Flathead River.

Senators Baucus and Tester have been working for several years to prevent energy exploration in the Flathead watershed. Early this year British Columbia officials announced they would block mining in the Canadian Flathead, and shortly thereafter the two senators said they would introduce legislation to do the same on the U.S. side of the border.

While that legislation, the North Fork Watershed Protection Act of 2010 (S. 3075), has been introduced, it remains pending in committee. If passed it would protect some 300,000 acres near the park from energy development. Its lack of movement hasn't stopped the senators from convincing energy companies to look elsewhere.

Along with the BP announcement, back in April the senators announced that ConocoPhillips, one of the world's largest energy companies, was giving up rights to explore for oil and gas on nearly 170,000 acres outside Glacier.

"In Montana, our outdoor heritage is in our blood -- camping, hiking, hunting and fishing are a way of life. We have a responsibility to leave our state in even better shape that we found it so future generations can carry on this legacy,” Sen. Baucus said in a prepared statement announcing the BP lease surrender. “Permanently protecting the North Fork for our kids and grandkids has been one of my biggest priorities for many years and today’s decision by BP is another step toward that goal.”

Sen. Tester added that the move by BP "is another right decision to keep this corner of Montana the way it was meant to be without costing taxpayers one penny. Over the past year we’ve come a long way in making sure this landscape remains one of the world’s most famous outdoor places prized for its wildlife, fish and clean water.”

The move was applauded by the National Parks Conservation Association's Crown of the Continent program manager, Michael Jamison.

“The effort to preserve the beauty of Glacier National Park and the quality of the Flathead River has received a major boost thanks to the tireless work of Montana Sens. Max Baucus and Jon Tester. It is largely because of the senators’ dedication and involvement in this issue that BP Energy Company has agreed to give up their oil and gas leases on land totaling more than 1,800 acres," said Mr. Jamison in a prepared staetment.

“This is an important step forward in preserving both the pristine beauty of this remarkable landscape and keeping the Flathead River clean and healthy for our children and grandchildren.”