Conservationists have asked a federal judge to declare federal approval of a Contra Costa County power plant a threat to the last sanctuary of the protected metalmark butterfly.
The lawsuit filed in federal court in San Francisco Thursday by Wild Equity Institute claims the U.S. Environmental Protection Agency authorized the Gateway Generating Station in Antioch in violation of the Endangered Species Act (ESA).
The suit claims the EPA authorized the plant, which is owned by Pacific Gas & Electric Co., to release nitrogen pollution into the Sacramento Delta and upstream of the San Francisco Bay near the only known habitat of the Lange’s metalmark butterfly.
The suit says the butterfly has been protected by the ESA since 1976. The only known habitat is the Antioch Dunes, an area that allowed the butterfly to evolve into a unique butterfly found nowhere else on earth.
Wild Equity contends the EPA was obligated to consult with the Fish and Wildlife Service before approving the plant.
The lawsuit also maintains that the plant will threaten the Antioch Dunes evening primrose and the Contra Costa wallflower.
As many as 25,000 of Lange’s metalmarks were believed to live in the dunes 50 to 100 years ago. But in the 1990s the numbers had dropped to 2,000. A wildfire then devastated 40 percent of its habitat, driving the population down to just 450.
By 2006, it was estimated just 45 adults remain, according to the lawsuit.
Wild Equity has asked the federal court to order the EPA to consult with the FWS on the effects of the power plant emissions.
Case: Wild Equity Institute v. U.S. EPA, No. 15-cv-2461