The Environmental Protection Agency is starting to roll back one of the most important Obama-era policies for fighting climate change: fuel efficiency standards. At the same time, the agency is also picking a knock-down, drag-out legal fight with states that want tougher car emission rules.

The EPA justified this proposal by invoking safety, arguing that higher efficiency standards make it harder to buy safer cars. But emails revealed this week that the EPA’s strange rationale didn’t hold up under the agency’s own analysis. In fact, the proposed changes would increase fatalities, as Ellen Knickmeyer reported for the Associated Press^[1]:

In announcing the mileage proposal earlier this month, officials with the EPA and Department of Transportation contended the mileage freeze would save about 1,000 lives a year. But in a June email, senior EPA staffers told the Office of Management and Budget — the White House office charged with evaluating regulatory changes — that it would slightly increase highway deaths, by 17 annually.

The “proposed standards are detrimental to safety, rather than beneficial,” William Charmley, director of the assessments and standards division of the EPA’s office of transportation and air quality, said in a June 18 interagency email, released Tuesday.

This directly contradicts what senior EPA officials said publicly about the proposed new fuel economy regulations^[2] released earlier this month by the EPA and the US Department of Transportation. “More realistic standards can save lives while continuing to improve the environment,” said EPA Acting Administrator Andrew Wheeler^[3] in a statement.

The proposal would ramp up fuel economy standards for cars and light-duty trucks until 2021, and then freeze them. The previous Obama-era standard continued to ratchet up fuel efficiency after 2021. The change would also revoke California’s waiver to set its own rules under the Clean Air Act, rules that 13 other states and the District of Columbia also follow.