Colorado moves to follow Calif. emissions standards

Colorado plans to join 12 other states and the District of Columbia in adopting California's low vehicle-emission standards, escalating the political and economic stakes for the auto industry as the Trump administration prepares to scale back national standards and even seeks to revoke California's authority to set its own limits.

Gov. John Hickenlooper, a Democrat, signed an Tuesday directing Colorado air-quality officials to begin a rule-making process to adopt the California clean car standards by year end. A final rule would make Colorado the first interior state to commit to the aggressive standards.

The battle over the emissions rule revolves around states' rights.

The 1970 Clean Air Act lets California set tougher air quality rules than the federal government because of its pre-existing efforts to combat poor air quality. Other states must follow national air-quality rules unless they choose to follow California's lead. In 2010, California and the auto industry agreed to follow aggressive standards developed by the Obama administration intended to double fuel-economy ratings to more than 50 mpg, or roughly 36 mpg in real-world driving, by the 2025 model year.

show the administration is considering freezing standards at the 2020 level through 2026 and weighing a plan to rescind California's waiver to regulate its own greenhouse gas emissions.

"With the Trump administration abdicating leadership on cleaning up tailpipe pollution and saving consumers money on gas, states need advanced vehicle standards to ensure their citizens get to drive the cleanest, most affordable cars on the market," Noah Long, senior attorney for the Natural Resources Defense Council, said in a statement. "This action will help ensure Coloradans still get clean air and cleaner cars."

The American Lung Association this year ranked Denver the 14th worst city in the nation for ozone pollution, to which vehicles heavily contribute. In May, describing the health impacts in the state if federal auto-emissions standards are relaxed and urged adoption of the California clean-car standards.

Automakers are seeking additional compliance flexibility from the Obama-era rules but don't want any changes not endorsed by California that could unravel the unified national program and raise costs by requiring vehicles tailored for different markets. With Colorado's move, states that follow California's rules represent more than 40 percent of the auto market.

Seventeen states and the District of Columbia filed suit in early May seeking to block the EPA's proposed changes.