WASHINGTON (AP) — California has proposed compromises to end a deadlock with the Trump administration on fuel economy and auto emissions standards but the administration hasn’t been willing to negotiate, according to the state’s top air pollution regulator.

California Air Resources Board Chairwoman Mary Nichols told a U.S. House committee Thursday that her agency has met with the administration more than a dozen times and has been open to adjustments in timing and flexibility of the standards, enacted a decade ago by the Obama administration.

At issue is a Trump administration plan to roll back the requirements, which would require cars to get 36 miles (58 kilometers) of real-world driving per gallon (3.8 liters) of gas by 2025. The goal is for Americans to fill up their gas tanks less frequently, sending fewer climate-changing emissions and pollutants into the air, one of the most aggressive measures in place to deal with the impact of climate change.

Instead, the administration has proposed halting the tougher standards at a 2020 requirement that cars achieve 30 miles (48 kilometers) per gallon of real-word driving. It also wants to take away California’s long-held ability to set its own, tougher standards, first granted in 1970 under the Clean Air Act as the state dealt with oppressive smog. Under the Obama rules, California and the federal government were on the same page.

It’s the second effort by the Trump administration to annul initiatives adopted under Obama to rein in fossil fuel emissions. 

The administration on Wednesday eased restrictions on coal-fired power plants.

“I would state categorically we proposed areas in which we would be willing to compromise with the administration and we never were told precisely what was wrong with any of those proposals,” Nichols told members of the House Energy and Commerce Committee. “We were simply told they were inadequate and that we somehow failed to do our job by not bringing a proposal that the administration found to be acceptable.”

She didn’t offer specifics on what compromise was offered.

Bill Wehrum, assistant Environmental Protection Agency administrator for air regulation, said earlier that the agency followed directions from President Donald Trump to try to make a deal with California, but he also told them to get the final rule done. A final proposal is expected soon, and the administration has said its preferred option is a freeze.

“My assumption is we’ll keep doing what the president said,” he told the committee. The administration broke off talks with California in February.

Nichols said she was responding to a letter from EPA Administrator Andrew Wheeler to the Republicans on the committee saying that she was unwilling to budge.

Rep. John Shimkus, R-Ill., read from the letter, quoting Wheeler as saying that when Nichols finally came up with a counterproposal, it was that California would agree to one extra year of the current standards. But Wheeler wrote that the offer had not been approved by her board or top state officials.

Nichols said that was false, with Wheeler taking words out of context.

Shimkus and others urged both sides to get together to avoid a long court fight that would delay a decision and cause uncertainty for consumers and the auto industry. Automakers have urged compromise and favor one increasing standard for the entire country.

But he said having California set standards for the entire nation would not go over well with constituents in southern Illinois, who don’t want government telling them what vehicles to buy. “We like big trucks, we like big engines, we like to haul trailers,” he said.

Republicans maintain that freezing the standards at 2020 levels would raise the price of cars, stopping people from buying newer vehicles that are safer, cleaner and more efficient.

They said the current standards were adopted a decade ago and were based on assumptions that gas prices would be $3 to $5 per gallon and people would shun trucks, SUVs and larger vehicles for smaller cars, gas-electric hybrids and battery-powered vehicles.

Democrats accused the administration of denying science on climate change. They started an inquiry into Trump administration ties with oil companies to determine if there was any coordination on the fuel economy rollback.

Rep. Jan Schakowsky, D-Ill., said the freeze would cut jobs, raise pollution and cost consumers money at the gas pump.

“The administration should abandon this proposal and end their assault on consumers, the environment and safety,” she said.