The Bureau of Land Management (BLM) violated the National Environmental Policy Act (NEPA) by not taking a hard look at the indirect impacts from onshore oil and natural gas production when it approved drilling on nearly 20,000 acres in the Piceance Basin, a federal judge in Colorado ruled Wednesday.

U.S. District Court for the District of Colorado Senior Judge Lewis Babcock said the Interior Department agency “acted in an arbitrary and capricious manner and violated NEPA by not taking a hard look at the foreseeable indirect effects resulting from the combustion of oil and gas” through its preliminary environmental assessment (EA) and an environmental impact statement (EIS).

“Defendants must quantify and reanalyze the foreseeable indirect effects from the emissions,” Babcock wrote in the decision in Citizens for a Healthy Community et al v. BLM et al, No. 1:2017cv2519.

The ruling is similar, but not identical, to one issued last month in U.S. District Court for the District of Columbia. In that case, the court ruled that BLM performed an inadequate job of considering the effects of climate change when it authorized oil and gas lease sales in the West, and ordered a temporary halt to drilling on more than 300,000 acres in Wyoming.

The Colorado case centers on plans to develop the Bull Mountain Unit, which includes about 19,670 acres of federal and private land 30 miles northeast of Paonia, CO. BLM created a master development plan (MDP) covering 2,300 acres within Bull Mountain that, as approved, allowed for construction of up to 33 well pads, 146 natural gas wells and four wastewater disposal wells.

BLM issued a final EIS for the MDP in July 2016 and a record of decision in October 2017. Five environmental groups sued the bureau over the plan in September 2017.

Although Babcock ruled in favor of the plaintiffs on the impacts from oil and gas production, it was by no means a clean sweep for the environmental groups.

In a departure from the Wyoming case, Babcock said BLM “took an appropriately hard look at cumulative climate change impacts in the EIS and EA.” He also said the bureau wasn’t required to use the social cost of carbon metric in its decision making, and said BLM sufficiently analyzed the impacts posed by hydraulic fracturing and the project’s cumulative impacts to air quality and water quantity.

The only other victory for the plaintiffs was Babcock’s ruling that BLM didn’t “sufficiently explain the scope for cumulative impacts” of the project on mule deer and elk in the region.

Babcock ordered the parties in the case to “confer and attempt in good faith to reach an agreement” over how to resolve the NEPA compliance issues. If there is no agreement, the judge said he would accept briefs from the parties until May 6.