PORTLAND, Maine (AP) — Maine environmental regulators are set to decide whether the state will join a growing number of states adopting new standards designed to grow the use of electric vehicles.

The rules, which originated in California, would require an increasing percentage of new light-duty vehicles to be zero emission vehicles every year. The new standards would start with 51% in 2028 and grow to 82% by 2032.

The Maine Board of Environmental Protection is set to vote on the proposal Wednesday in a vote that has been anticipated for weeks. The proposal has encountered a mixed reception in Maine, where some have said it would speed up the already-growing adoption of electric vehicles.

“Consumers in Maine are already rapidly adopting electric vehicles,” said Sarah Krame, staff attorney with Sierra Club Environmental Law Program, in testimony. “Demand is so strong that lack of supply has been a major constraint on Maine residents looking to purchase EVs, with waitlists several months long for certain models.”

Opponents of the proposal, including prominent state Republicans, have described the move as wrong for the state’s economy and geography, and said it would heap costs onto consumers.

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“Extremists seem to think that only 6% of consumers want EVs because the government hasn’t forced them to buy one. The truth is this plan isn’t feasible because of Maine’s geography and infrastructure,” said House Republican Leader Billy Bob Faulkingham late last year.

A dozen states have adopted the electric vehicle standards, and 17 states have adopted all or part of California’s low-emission and zero-emission vehicle regulations, according to the California Air Resources Board. The proposals have found support in Democratically-controlled states.

Meanwhile, sales of electric vehicles have begun to slow. The Biden administration announced new emissions standards on Wednesday that could boost the industry.

Transportation is a major contributor to Maine’s greenhouse gas emissions, and Democratic Gov. Janet Mills has made tackling climate change a major piece of her tenure.

The state received hundreds of comments about the electric vehicle proposal in advance of Wednesday’s meeting. The Alliance for Automotive Innovation, a trade group that represents car manufacturers, testified in support of the proposal.

The proposal might still need to clear more hurdles, as state lawmakers are considering legislation that could allow them to ultimately make the final decision.