The Bureau of Land Management must release the names and addresses of people with grazing permits on the nation's public land, a federal judge has ruled.

The decision, handed down in Idaho's U.S. District Court on Monday, came after two environmental groups sued for the names under the Freedom of Information Act.

Assistant U.S. Attorney Nicholas Woychick said Tuesday he was still reviewing the ruling and it was not yet clear if the BLM would appeal the decision. If the agency doesn't appeal, it could be forced to turn over the names, addresses and other information about those who hold nearly 18,000 grazing permits and leases on nearly 160 million acres across the West.

In the lawsuit filed last year, Western Watersheds Project and WildEarth Guardians contended that the BLM wrongly said the names, addresses and other grazing permit information was protected from release under an exemption that allows agencies to keep from releasing medical records and other information that could constitute an unwarranted invasion of personal privacy.

U.S. District Court Judge Candy Dale said the public interest in monitoring the BLM's rangeland grazing program outweighed the minimal privacy interests of the grazing permit holders.

"Although the Court acknowledges that there are no restrictions on the number or size of grazing permits that each permitee may hold, the court finds that there is a substantial interest in understanding the scope of the grazing and rangeland program, particularly in light of the environmental impacts associated with grazing and the amount of tax dollars spent on the grazing program itself," Dale wrote in the 28-page ruling.

Mark Salvo, a director with WildEarth Guardians, said the names and addresses of grazing permit holders serve as the key to understanding the BLM grazing program and allows the public to answer an "infinite number of questions" about public land policies.

"One of the examples that we gave the court was that until now, it was virtually impossible to discover if a particular BLM grazing permitee also held Forest Service grazing permits and if they also received agricultural subsidies from ag support programs," Salvo said. "We offered one example, of a corporate grazer that we knew had BLM grazing permits."

The organization was able to cross-reference that corporation name using already public Forest Service and US Department of Agriculture databases to learn that the company, which grazed sheep for wool, had several grazing permits on BLM and Forest Service land and was also getting hundreds of thousands of dollars in wool subsidies, Salvo said.

"Then you can track back and discover what kind of impacts that has — how many times that company has been in violation, how many of the allotments were in poor condition, so the public can better understand how its lands and resources are being used," he said.