Washington, D.C. - Aug. 2, 2018

1. Sarah Sanders at White House press briefing

2. SOUNDBITE (English) Sarah Sanders, White House press secretary:

"What the EPA released yesterday was a notice of proposed rule-making, not a final rule. The notice lays out a series of options for how to go forward with CAFE standards. And the notice asks for comments on the range of options. We're simply opening it up for a comment period and we'll make a final decision at the end of that."

Los Angeles - Aug. 2, 2018

3. Becerra listens to reporter's question at press conference at UCLA campus

4. SOUNDBITE (English) Xavier Becerra, California Attorney General:

"We intend to stand firm and protect the existing clean car standards that our nation has in place. And California will protect its waiver to continue to lead the fight to have cleaner air and cleaner-burning vehicles."

Oakland, California - Aug. 2, 2018

5. Anair looking at Trump fuel efficiency proposal on laptop

6. Laptop screen shows fuel efficiency proposal

7. SOUNDBITE (English) Don Anair, Union of Concerned Scientists, deputy director of clean vehicles program:

"Today the Trump administration proposed rolling back the most effective climate policy on the books of the United States. Essentially they decided to freeze fuel economy and emissions standards at 2020 levels, which will be bad for consumers, bad for oil and energy security, and bad for the environment."

Citing safety, the Trump administration on Thursday proposed rolling back car-mileage standards, backing away from years of government efforts to cut Americans' trips to the gas station and reduce unhealthy, climate-changing tailpipe emissions.

If the proposed rule becomes final, it could roil the auto industry as it prepares for new model years and weaken one of the federal government's chief weapons against climate change — regulating emissions from cars and other vehicles. The result, opponents say, will be dirtier air and more pollution-related illness and death.

"We intend to stand firm and protect the existing clean car standards that our nation has in place. And California will protect its waiver to continue to lead the fight to have cleaner air and cleaner-burning vehicles," said California Attorney General Xavier Becerra.

The proposal itself estimates it could cost tens of thousands of jobs — auto workers who deal with making vehicles more fuel efficient.

The administration also said it wants to revoke an authority granted to California under the half-century-old Clean Air Act to set its own, tougher mileage standards. California and 16 other states already have filed suit to block any change in the fuel efficiency rules.

The administration will now seek public comment on its proposal and a range of other options, including leaving the tighter, Obama fuel standards in place.

Some Republican lawmakers supported the mileage freeze, but environmental groups and many states assailed it.