One month after a federal judge ruled that the Interior Department’s Bureau of Land Management (BLM) did not violate environmental law when it approved applications for oil and gas drilling in a sensitive area of northwest New Mexico, the state’s two Democratic senators introduced a bill to withdraw the area from future lease sales.

Sens. Tom Udall and Martin Heinrich on Tuesday introduced the Chaco Cultural Heritage Area Protection Act. The bill calls for withdrawing 316,076 acres containing oil, natural gas, coal and other minerals owned by the federal government within the Proposed Chaco Protection Zone from future leasing and development. The zone, which measures 909,000 total acres, surrounds the Chaco Culture National Historical Park.

In a joint statement, Udall said the greater Chaco region “is being threatened by expanding energy development.” Heinrich concurred, adding “Chaco Canyon is a sacred site that is revered by all New Mexicans and deserves to be protected from any harmful development that would damage its precious historical and cultural resources.”

The bill follows a ruling last month in U.S. District Court for the District of New Mexico that disappointed a coalition of environmental groups that had sued the BLM in March 2015, after the Interior agency approved at least 130 applications for permits to drill (APD) targeting the Mancos Shale and the Gallup formation.

The groups claimed the BLM had violated the National Environmental Policy Act (NEPA) and the National Historic Preservation Act (NHPA) when it approved the APDs. But in April, District Court Judge James Browning disagreed and dismissed the lawsuit.

“The BLM adequately involved the public in its NEPA process, as it gave notice of finalized environmental assessments’ availability through its online NEPA logs, and sent notices of and hosted public meetings at each proposed well’s site,” Browning said. “The BLM did not violate the NHPA, because it considered the effects on historical sites within the wells’ areas of potential effects.”

WPX Energy Production LLC, Encana Oil & Gas (USA) Inc., BP America Co., ConocoPhillips, Burlington Resources Oil & Gas Co. LP, Anschutz Exploration Corp. and the American Petroleum Institute intervened on behalf of the defendants, which was Diné Citizens Against Ruining our Environment et al v. Sally Jewell et al, No. 15-0209.

Last March, Interior Secretary Ryan Zinke postponed an oil and gas lease sale near Chaco. The sale was to include 25 parcels covering 4,434 acres in New Mexico’s Rio Arriba, Sandoval and San Juan counties, which are in the Four Corners area of the state.