WASHINGTON, Nov 9 (Reuters) - The U.S. Environmental Protection Agency on Thursday proposed to undo pollution rules on remanufactured heavy duty vehicles known as "gliders," which environmentalists say generate as much as 40 times the pollution of modern engines.
The vehicles have a used engine in a new frame and rules introduced under former President Barack Obama, a Democrat, said new trucks on the road must use more efficient, less polluting engines.
The EPA has previously said that if gliders were allowed through 2025, they would make up 5 percent of the freight trucks on the road but would account for one third of all nitrogen oxides and particulate matter emissions from the heavy truck fleet.
The EPA under President Donald Trump, a Republican, said it was proposing gliders should not be regulated as "new motor vehicles" or "new motor vehicle engines" under the Clean Air Act. EPA Administrator Scott Pruitt said in a statement that the regulation "threatened to put an entire industry of specialized truck manufacturers out of business."
Sierra Club's Andrew Linhardt said the move to rollback the rules is "a blatant attempt by the Trump administration to rig the system for the glider industry at the expense of American families and jobs."
Glider companies told the EPA in July that remanufactured glider trucks are 25 percent cheaper than new vehicles and left unchanged the regulation couple prompt hundreds of layoffs. They urged Pruitt to reverse the regulations imposed under President Barack Obama.
Volvo Group North America, Cummins Inc and Navistar International Corp in September opposed Pruitt's move and said the Obama rule should remain in place. Glider kits "should not be used for circumventing purchase of currently certified powertrains." The move could inflict "uncertainty and damage to our industry," they added.
Environmentalists said sales of gliders have risen tenfold from the 1,000 sold annually in 2007. EPA estimates that about 10,000 gliders are manufactured annually, comprising less than five percent of heavy duty trucks.
American Trucking Associations' environmental counsel Glen Kedzie said the EPA's "position supporting the continued growth of the glider kit industry that produces the highest emitting equipment on our nation's highways is perplexing."
In August 2016, the Obama administration issued final rules to cut greenhouse gas emissions from medium and heavy duty trucks through 2027, a sector that accounts for 20 percent of carbon pollution from vehicles.
The commercial vehicle rules would cut 1.1 billion metric tons of greenhouse gas emissions, the Obama administration estimated. Fuel costs would be cut by about $170 billion, surpassing the $25 billion projected costs for new technology, it said. (Reporting by David Shepardson; editing by Grant McCool)