Several state and city governments have joined environmental groups in stoking the debate over the U.S. Environmental Protection Agency’s role in regulating motor-vehicle emissions.

Attorneys general from 17 states, along with environmental organizations, the District of Columbia, Baltimore and New York City petitioned the U.S. Court of Appeals for the D.C. Circuit on April 2 to force EPA to make a decision on whether to regulate greenhouse gas emissions from motor vehicles, including cars, light trucks and SUVs, under the federal Clean Air Act. The petition asks the court to require EPA to respond within 60 days.

The court filing came exactly one year after the U.S. Supreme Court’s Massachusetts v. EPA, which found the agency had the authority to regulate greenhouse gases. Under the ruling, EPA must determine whether greenhouse gases are endangering public health or welfare and, if so, begin regulating them.

“Once again, the EPA has forced our hand, which has resulted in our taking this extraordinary measure to fight the dangers of climate change,” said Massachusetts Attorney General Martha Coakley.

EPA Administrator Stephen Johnson told Congress on March 27 that the agency planned to open a public comment period on the potential risks of greenhouse gases.

House Oversight and Government Reform Committee Chairman Henry A. Waxman (D-Calif.) said Johnson’s move was “a transparent delaying tactic and a major reversal of EPA’s position.”

But some industry and non-profit organizations praised EPA’s plan, arguing the comment period is consistent with the Supreme Court’s decision and that the court’s ruling did not set a deadline for the agency to act. “A wave of costly new regulations is the last thing the economy needs,” said Ben Lieberman, senior policy analyst on energy and environment at the Heritage Foundation in a March 28 memo.

Lieberman added that the EPA decision “will allow for comment on the economic implications of various options open to the EPA for regulating motor vehicles and on other critical issues.”