ANTIOCH -- An environmental justice coalition is threatening to sue the U.S. Environmental Protection Agency for allowing emissions from PG&E's natural gas power plant to jeopardize native wildlife -- including a near-extinct butterfly found only in the area.
According to the July 24 letter from the Wild Equity Institute, the federal agency violated the Endangered Species Act -- mainly impacts from nitrogen emissions -- when it issued Clean Air Act permits for the Gateway Generating Station without consulting the U.S. Fish and Wildlife Service.
"PG&E has already been put on notice twice of their violations and few things have changed since, so we decided to renotice them," Wild Equity Institute attorney Laura Horton said. "This is PG&E's last chance to do the right thing."
Wild Equity officials say the emissions jeopardize the Lange's metalmark butterfly, which is found only at the Antioch Dunes National Wildlife Refuge, by helping invasive weeds grow and smothering its food supply.
The weed growth also puts two endangered plant species at the Dunes -- the Antioch Dunes evening primrose and the Contra Costa wallflower -- at risk.
The coalition previously threatened to sue over the Gateway plant. Similar petitions were sent in December 2010 and December 2011.
Communities for a Better Environment officials also contend in the letter that Gateway's emissions harm local communities by contributing more pollution and soot to an area with a disproportionate amount of power plants.
PG&E spokeswoman Tamar Sarkissian said Thursday that Gateway, which started operating in early 2009, is state-of-the-art and emits extremely low levels of nitrogen oxides, while being in full compliance with limitations set by its clean air permits.
The letter gives 60 days for the agency to try and remedy the situation, or the groups will file a lawsuit in U.S District Court of Northern California, Horton said.
An EPA spokesman for the California region said Thursday he had not received the letter and could not comment on it.
The group has also targeted four other power plants -- all located within a mile of each other on the Antioch-Oakley border.
Earlier this month, the coalition agreed to a $2 million settlement with Radback Energy to offset any harm the Oakley Generating Station may cause native endangered wildlife and low-income residents.
"Hopefully, that settlement acts as a kind of precedent," Horton said.
The Antioch shoreline refuge is the only place in the world where the bright reddish-orange Lange's metalmark is found. Their numbers have dwindled from more than 25,000 early in the 20th century to 2,500 in the late 1990s and as low as 32 in 2011.
PG&E officials point out that they have entered into a voluntary Safe Harbor Agreement to improve the 12 acres of dune habitat on its property for the Lange's metalmark butterfly and plant species. They also hold twice-a-year weed control days, created a vegetation management plan and developed a plan to restore the sand dunes, Sarkissian said.
Invasive plant cover has been reduced by over 26 percent since 2008, she said.
"PG&E has and will continue to make great efforts to help protect the Lange's metalmark butterfly species," Sarkissian said.
Contact Paul Burgarino at 925-779-7164. Follow him at Twitter.com/paulburgarino.