A legal firm representing a group of small trucking and construction business owners in California has filed a federal lawsuit challenging the federal government's new fuel-economy standards for heavy duty and medium duty vehicles.

The suit, filed by Pacific Legal Foundation, charges that federal officials were legally required to submit the regulations for independent scientific scrutiny, but failed to do so.

PLF represents the California Dump Truck Owners Association, Southern California Contractors Association, Dalton Trucking of Fontana, Calif., and Delta Construction Company of Sacramento.

The regulations, announced in August, are the first-ever federal restrictions on greenhouse gas emissions from medium and heavy-duty vehicles. They were promulgated jointly by the U.S. Environmental Protection Agency and the National Highway Transportation and Safety Administration.

"Federal law says EPA can't issue new clean-air regulations without submitting the proposals for independent scrutiny by its Science Advisory Board," said PLF Senior Staff Attorney Ted Hadzi-Antich. "EPA recklessly ignored this requirement."

The Science Advisory Board is a panel of scientists from universities, research institutions and other highly regarded organizations, empowered by federal law to review any new "criteria document, standard, limitation, or regulation" that EPA proposes to issue under the Clean Air Act, the attorney explained.

Hadzi-Antich says the new rules bring "unprecedented federal intrusion into the manufacturing and use of medium and heavy-duty vehicles" and would add many thousands of dollars to the costs of new trucks.

The attorney accused the federal government of wanting "to dictate the actual design of trucks, tractors, and other heavy-duty vehicles used throughout the economy."

PLF said it submitted comments on the proposed regulations to EPA on behalf of a number of small businesses and trade associations that would be adversely affected by the proposed regulations. It says those comments were essentially ignored by EPA.

While one business owner quoted by the attorneys said he was concerned that his trucks would be "declared obsolete," the regulations only affect new trucks and buses built in 2014 through 2018. No retrofits are required.

PLF's lawsuit is filed as a petition for review with the U.S. Court of Appeals for the District of Columbia Circuit.