Environmental groups have sued the Trump administration over offshore drilling tests, which could harm hundreds of thousands of marine mammals such as dolphins and whales.

The lawsuit filed in federal court in Charleston, South Carolina, claims the National Marine Fisheries Service violated the Marine Mammal Protection Act, the Endangered Species Act and the National Environmental Policy Act when it issued five permits for the use of seismic air guns.

The air guns fire continuous blasts to ascertain whether deposits of oil and gas are present, and is a precursor to what could be the first drilling in federal waters off the US eastern seaboard in decades.

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By the federal government’s own estimates, airgun testing could harm hundreds of thousands of marine mammals such as dolphins and whales. Of particular concern is the endangered North Atlantic right whale, with only around 440 individuals left, including fewer than 100 breeding females.

“This action is unlawful and we’re going to stop it,” Diane Hoskins, campaign director at Oceana, said in a news release. “The Trump administration’s rash decision to harm marine mammals hundreds of thousands of times in the hope of finding oil and gas is shortsighted and dangerous.”

The coalition includes Oceana, the Southern Environmental Law Center, the Natural Resources Defense Council, Earthjustice, Center for Biological Diversity, Surfrider Foundation and the Sierra Club.

The blasts are conducted in preparation for potential offshore drilling, which the administration has proposed to expand from the Atlantic to the Arctic and Pacific oceans. The five-year plan would open 90% of the nation’s offshore reserves to private development.

Survey vessels will be required to carry observers to listen and watch for marine life and alert operators if a protected species comes within a certain distance. Surveys would be shut down when certain sensitive species or groups are observed, and penalties could be imposed for vessels that strike marine animals.

Trump administration to allow seismic blasting harmful to marine creatures Read more

But the precautions aren’t enough for environmental groups, who have said the blasts can disturb wildlife. Industry groups say the surveys have been conducted around the world for decades, with little adverse impact.

The drilling issue has been an emotional one along South Carolina’s coast, with cities and municipalities mounting vocal opposition. But there are still supporters of the idea, which some say could mean an economic boon for an area increasingly reliant on tourism.

The drilling issue has united some Democrats and Republicans along the east coast in opposition to it. In South Carolina’s first congressional district, Republican Katie Arrington a supporter of Donald Trump who initially said she stood by his drilling plans later backed off that support amid a growing wave of drilling opposition in the coastal district she aimed to represent.

Arrington ultimately lost the general election to Joe Cunningham, a Democratic drilling opponent who collected support from coastal Republican mayors. Voters said they had been turned off by what they saw as Arrington’s flip-flop on the issue, and they turned instead to Cunningham’s consistency.

On Monday, ahead of the lawsuit’s filing, Cunningham told the AP he backed the legal effort, which would pair with legislative action he plans to take up in the US House.

“I’m going to go up to DC and fight like hell,” Cunningham said. “These lawsuits are one tool in our bag that we’re going to use.”