Two environmental groups filed a new legal challenge to the Biden administration’s approval of a yet-to-be-built project that would send the Alaska North Slope’s vast reserves of natural gas to markets.

In a petition filed with the 9th U.S. Circuit Court of Appeals, the Center for Biological Diversity and the Sierra Club argued that federal agencies failed to properly consider harms that the massive natural gas project would cause to Endangered Species Act-listed animals living in the affected marine areas: polar bears, Cook Inlet beluga whales and Eastern North Pacific right whales.

The petition was filed against the U.S. Fish and Wildlife Service and National Marine Fisheries Service, along with the agencies’ parent departments, the Department of the Interior and Department of Commerce.

The Biden administration last year renewed an approval of exports from the project, which has been pursued in various forms since the 1970s but never built. The current plan is being promoted by the state-owned Alaska Gasline Development Corp. It proposes a 42-inch-diameter pipeline running about 800 miles from Prudhoe Bay on the North Slope to tidewater at Cook Inlet, where a new facility would convert the product to liquefied natural gas and load it onto tanker vessels for export to Asian markets.

The Biden administration’s most recent approval, which follows numerous other permits and approvals over the years, was based on flawed biological reviews, the environmental groups argued.

“The rubber-stamp approval of the Alaska LNG project was reckless in many ways,” Sierra Club Alaska Chapter Director Andrea Feniger said in a statement. “The project will be devastating to vulnerable wildlife already struggling to face the catastrophic impacts of climate change. The agencies responsible for assessing the impacts on whales, polar bears, and other species neglected to take proper care in evaluating the full scope of harm Alaska LNG will cause.”

The lawsuit comes about a week after a different case was filed that challenges the project. On May 22, a group of young Alaskans sued the state to block the project because of its anticipated carbon emissions and impact to climate change. That case was filed in Alaska Superior Court in Anchorage.

The cases are unrelated and the timing of the two is coincidental, said Kristen Monsell, senior attorney for the Center for Biological Diversity. However, “it just goes to show how damaging this project would be in a variety of different ways,” she said by email.

The environmental groups’ legal claim was filed directly in the appeals court, bypassing lower courts, in accordance with the Natural Gas Act, Monsell said.

Under the act’s judicial review provision, challenges to permits for LNG projects other than those issued by the Federal Energy Regulatory Commission are to be filed directly in appeals courts in which projects are located, she said.

A previous lawsuit challenging the export approval was filed last August by the same environmental groups in a different court. That challenge, filed in the U.S. Court of Appeals for the District of Columbia against the U.S. Department of Energy, alleged that federal approval decisions overlooked both climate and nonclimate environmental impacts of the yet-unbuilt LNG project. That lawsuit remains pending; the most recent action was a series of briefs filed by opposing parties earlier this month.

A spokesperson for the Alaska Gasline Development Corp., responding to the latest legal challenge, said numerous reviews have already found the project to be worthwhile.

“Alaska LNG has withstood intensive environmental scrutiny by two successive administrations because of its obvious and abundant benefits, which include reducing global emissions by up to 2.3 billion tons, strengthening allied energy security, and finally ending longstanding air quality problems plaguing Interior Alaska villages and communities,” corporation spokesperson Tim Fitzpatrick said by email.

 The Alaska North Slope has about 35 trillion cubic feet of known natural gas reserves, with more than that believed to exist in different areas of the region, including both conventional sources that would be produced through normal drilling technology and unconventional sources that would require more advanced techology, according to the U.S. Geological Survey estimates.

While oil has flowed from the North Slope since 1977, the natural gas that exists in the same fields has been stranded without a market and without any means of delivery to a market. The natural gas that is pumped up with oil in the North Slope fields is mostly reinjected into the ground to help push up more oil.

State, federal and industry officials have for decades pursued plans for pipelines to send that natural gas to markets – including a plan that was endorsed by then-President Jimmy Carter in the 1970s – but none has proved economically feasible.

The Alaska Gasline Development Corp. estimates its plan would cost $39 billion.

The Alaska Legislature, in its operating budget passed earlier this month, appropriated money to continue the state-owned corporation’s operations through the fiscal year starting on July 1.

Legislators allocated about $2.5 million in general-purpose state money to the Alaska Gasline Development Corp., less than the $4.5 million the corporation had requested at the start of the session. The corporation can also spend up to $3.1 million from a special gasline-specific account, under the operating budget.

Earlier in the session, some lawmakers expressed skepticism about continued state funding of the Alaska Gasline Development Corp. and its efforts.

Reporter James Brooks contributed to this article.