The Center for Biological Diversity (CBD) and the Native American Wishtoyo Foundation are suing the Obama administration for allowing hydraulic fracturing (fracking) in federal waters without properly evaluating the risks.

The move comes in anticipation of a push from the incoming Trump administration to end the longstanding prohibition on offshore drilling in federal waters off California. The groups filed the lawsuit in a federal district court in Los Angeles.

The two organizations said that they expect oil companies to push again to drill and frack in federal waters near Southern California’s Malibu and Orange counties, and to the far north off Humboldt County. They see the election of Donald Trump as an eventual spur for an upcoming push by the industry.

Opposition groups are focused on the results of an environmental assessment (EA) released earlier this year by the Interior Department’s Bureau of Safety and Environmental Enforcement (BSEE) and Bureau of Ocean Energy Management (BOEM). The EA evaluated potential impacts from using well stimulation treatments on the 23 oil and gas platforms currently in operation on the Outer Continental Shelf (OCS) offshore California.

In 2015, San Francisco-based CBD sued Interior for permitting fracking off the California coast, alleging it threatens ocean ecosystems, coastal communities and marine wildlife.

“Federal officials’ failure to carefully study the risk of offshore fracking is doubly disturbing after Trump’s election,” said Kristen Monsell, a CBD attorney. Monsell alleged that “every offshore frack increases the risk of poisoning our ocean and that danger could now spread along the [California] coast.”

Local Chumash Native American tribes joined in the legal action, contending that the federal agencies have failed to examine the impacts fracking could have on natural and cultural resources. Chumash maritime peoples depend on the offshore resources “to sustain our lifeways and connect with our ancestors,” according to Mati Waiya, executive director of the Wishtoyo Foundation.

The latest action is an attempt to get the Obama administration in its waning days to forestall expanded drilling off the California coast under the Outer Continental Shelf Lands Act, which the plaintiffs claim gives the president authority to “withdraw from disposition” any of the unleased lands of the Outer Continental Shelf.

The EA released earlier this year was characterized as “drawing on the best available science,” and providing information and analysis on the use of well stimulation treatments in federal waters offshore California, BOEM Director Abigail Ross Hopper said in May. “The comprehensive analysis shows that these practices, conducted according to permit requirements, have minimal impact.”

The EA was required to be completed by the end of May under a settlement agreement finalized in February between Interior and some conservation groups.