The US-based vehicle manufacturing trade group AIAM is to intervene on the side of the US Environmental Protection Agency (EPA) in the lawsuit brought by the State of California against EPA concerning California's greenhouse gas emissions regulations.

"This is not a lawsuit to resist greenhouse gas emissions regulation.  Rather, our intervention is focused on only one issue - who should set those standards," said AIAM president and CEO Michael Stanton.

"We believe that for important policy and legal reasons, it is the federal government that should set those standards."

In January, five non-profit groups filed a lawsuit challenging the 19 December decision by the EPA to deny California its request to implement its landmark law limiting global warming pollution from new vehicles.

The state of California also filed its own legal challenge to EPA's decision in the same court.

"AIAM has long supported efforts to reduce greenhouse gas emissions and improve fuel economy," said Stanton.

However, he added that at the same time, it was "critically important" that when it came to fuel economy and motor vehicle greenhouse gas emissions, automobile manufacturers be subject to a single national fleet standard set at the federal level. 

"This is an issue on which there is unanimity within the industry," Stanton said.

AIAM said that it believes that the EPA's decision to deny California's waiver application, which sought to impose state-level greenhouse gas emissions regulations, is critical in maintaining fleet fuel economy requirements at the federal level. This would avoid, it says, unnecessarily burdensome compliance on a state-by-state basis for no additional environmental benefit.

"AIAM believes firmly that the automobile industry must do its part to address this important national and international issue," Stanton said. "However, we must do so in a sensible and efficient manner that preserves national uniformity in this important regulatory area."

AIAM - The Association of International Automobile Manufacturers - is a trade association representing 14 international motor vehicle manufacturers who account for 40% of all passenger cars and light trucks sold annually in the US.