On Wednesday, the Land and Water Conservation Fund (LWCF) will expire, leaving thousands of acres of public lands, including portions of national parks, at risk of being developed by private interests, according to the Wilderness Society.

The fund has been a major resource for state and local conservation efforts and outdoor recreation industries. The LWCF, established in 1965, was funded through offshore oil and gas royalties. Hundreds of millions of dollars from the LWCF have been allocated to all 50 states to preserve iconic public lands, according to a press release from the Evangelical Environmental Network.

A bill was proposed in July to permanently fund the LWCF, but it did not pass.

“It’s disheartening to see this broadly supported, bipartisan, highly successful program derailed by a handful of ideologues,” Michael Brune, director of the Serra Club, said in a press release. “We need a return to commonsense legislating that benefits the American people; this program must be reauthorized as soon as possible.”

A teleconference hosted by the Evangelical Environmental Network will be held on Thursday to discuss future action, according to the press release.