Washington regulators will forgo analyzing the costs of adopting California’s ban on new gas- and diesel-powered cars, pickups and SUVs beginning in 2035.

The Department of Ecology also won’t analyze requiring a gradually increasing percentage of new heavy trucks to be electric. The department plans to impose both California rules this year.

Ecology spokesman Andrew Wineke said cost-benefit analyses aren’t appropriate because the department has no choice but to adopt rules identical to California’s.

The Washington Legislature in 2020 passed a bill requiring the state to do whatever California did in the future about vehicle emissions.

“Because the requirement is in the statute, we have not conducted a separate cost-benefit analysis on the impacts of those policies in Washington,” he said in an email.

A cost-benefit analysis justifies a rule, estimates the expense, reviews alternatives and informs public comments. By committing to adopt future California laws, Washington legislators more than two years ago foreclosed on in-state debate about banning gas- and diesel-fueled vehicles.

Washington lawmakers this year directed state agencies to come up with a plan for a ban. Legislators set 2030 as a “target.” California has now set a hard date.

The Inslee administration celebrated the Aug. 25 move by the 14-member California Air Resources Board as a landmark in the fight against climate change.

“We’re excited to join the clean transportation revolution when we adopt our expanded rule for zero-emission vehicles in December,” Ecology tweeted.

Besides the two California laws, Ecology plans to finalize rules for cap-and-trade and a low-carbon fuel standard before the end of the year.

Ecology has analyzed the costs and benefits for those two climate-change laws, which were passed by the Legislature after lengthy debates.

The Western States Petroleum Association said Ecology should do a comprehensive analysis on all four overlapping laws.

Fuel prices are volatile and unpredictable, but the laws will push up the cost of providing gasoline and diesel, petroleum association spokesman Kevin Slagle said.

“Unfortunately, none of the agency analysis is looking at those costs,” he said.

The Clean Air Act requires states to follow either federal or California emission standards accepted by the Environmental Protection Agency. California has special status because its 1960s tailpipe emission laws predated the federal law.

Many states, including Oregon, may follow California’s lead on electric vehicles. In Oregon, the decision will be up to the Environmental Quality Commission.

The commission does not have to adopt the California rule, Department of Environmental Quality spokesman Harry Esteve said. “It’s not coming from the perspective, we have to do it.”

Midwest corn and soybean farmers and 17 states are suing the EPA to prevent states from prohibiting gasoline and diesel vehicles.

The suits, filed in the Appeals Court for the District of Columbia, claim the EPA has misapplied the Clean Air Act by approving California’s electric-vehicle mandates.

The suits also claim that the EPA can’t single out California for special treatment.

Washington and Oregon are among 20 states that have intervened to defend the EPA and California’s emission standards.