Environmentalists, frustrated that regulators rejected rules to broaden electric vehicle use in Maine, have filed a lawsuit accusing state officials of failing to comply with targets for reduced greenhouse gas emissions.

The Conservation Law Foundation, Sierra Club and Maine Youth Action on Friday sued two state agencies in Cumberland County Superior Court.

The groups said the Department of Environmental Protection and Board of Environmental Protection, which provides oversight of the DEP, are responsible for implementing Maine’s Climate Law, requiring greenhouse gas emissions to be cut at least 45% from 1990 levels by 2030 and 80% by 2050.

The environmentalists have asked the court to order the board to adopt rules that comply with the state’s climate law, with a priority for transportation on or before Nov. 1. They also are asking the court to order the agency to adopt EV rules or an alternative rule by the same date. That date is one month before the Dec. 1 deadline for the Maine Climate Council to update the state climate plan.

Last month, the board rejected proposed EV standards that would have required increasing the share of electric and hybrid cars and trucks sold in Maine to 51% of all vehicles sold in 2028 and 82% of all vehicles sold in 2032. About 6% of new cars sold in Maine last year were electric vehicles or hybrids.

The lawsuit says that in the nearly five years since Maine’s Climate Law was enacted and the more than 2 ½ years since the DEP’s legal obligation to enact rules to implement the law, the Board of Environmental Protection has adopted only two rules aimed at Maine’s Climate Law’s requirements, and not a single rule aimed at scaling back pollution caused by tailpipe emissions.

The board has “abdicated its statutory obligation, rejecting three transportation decarbonization rules,” the environmentalists said.

David Madore, deputy commissioner at the Department of Environmental Protection, said the agencies do not comment on pending litigation.

Several members of the board said they were reluctant to approve a major change in private transportation and said the authority to do so belongs to the Legislature. Lawmakers quickly approved legislation, signed into law by Gov. Janet Mills, giving lawmakers the final say on EV rules. But the Legislature is not expected to reconvene until Dec. 4, after new members have been elected.

However, Emily Green, senior attorney at the Conservation Law Foundation, said the board can – and should – adopt the rule, even though the Legislature has the last word.

“Ultimately, the department and the board are supposed to make sure we get it all done,” she said.

When the Press Herald asked earlier this month about how the state would reach its emissions goals without EV rules in place yet, Anthony Ronzio, a spokesperson for the Governor’s Office of Policy Innovation and the Future, said it was “premature to speculate” until the Maine Climate Council updates the state climate plan later this year.

Republicans and some Democrats in the Legislature joined car dealers in opposing the EV rules. Critics said Maine does not have enough chargers, particularly in the state’s rural expanses. Senate President Troy Jackson, D-Allagash, said he favors incentives rather than mandates to promote EVs.

The lawsuit says the state’s climate plan, “Maine Won’t Wait,” identifies transportation as accounting for 54% of greenhouse gas emissions in the state. And the climate plan declares that the “most significant reductions of greenhouse gas emissions in Maine’s transportation sector will come through the long-term and large-scale electrification of our transportation systems,” the lawsuit says.

Two of the plaintiffs in the case – the Conservation Law Foundation and the Sierra Club – had petitioned the board last year to adopt EV rules. The Natural Resources Council of Maine also was involved in that effort but is not part of the lawsuit.

The petition, which was signed by more than 150 Mainers, won initial approval in an October 2023 straw poll by the board. Board members said then that their eventual vote would likely be challenged by state lawmakers.