Just as Scott Pruitt’s tenure as administrator came to an end on Friday, the Environmental Protection Agency confirmed that, through the end of 2019, the agency will not enforce an annual cap of 300 glider kits per manufacturer that was imposed back in January.
The move came after intense lobbying by a small set of manufacturers that sell glider trucks, which use old engines built before new technologies reduced the number of emissions.
It was just as strongly opposed by an unusual alliance of public health groups, environmental groups, and major industry players like United Parcel Service, the largest truck fleet owner, and Volvo Group, one of the largest truck manufacturers.
The glider truck concept began so the engines of newer trucks that had been involved in accidents could be moved to new truck bodies. But as the emissions control requirements went into effect in recent years, companies like Fitzgerald Glider Kits of Crossville, Tenn., began to attract thousands of buyers from around the United States, getting trucks they argued were cheaper to run.
Fitzgerald made about 3,000 of these trucks in 2017, a production rate that it will now be allowed to return to. An estimated 10,000 glider trucks were sold nationally in 2015 — about 4 percent of new heavy-duty truck sales — and production could soon return to that level.
“The Agency is exercising its enforcement discretion in 2018 and 2019,” Molly Block, an agency spokeswoman, said in a statement. It is notifying glider manufacturers that even though the limit legally remains in place, the companies can effectively ignore it.
The rollback was immediately condemned by environmental groups, which have appealed to the White House to block the E.P.A. from creating the loophole.
“Pruitt and Wheeler are creating a loophole for super polluting freight trucks that will fill our children’s lungs with toxic diesel pollution, ignoring public comments from moms and leading businesses across the country,” said Vickie Patton, general counsel at the Environmental Defense Fund.
Mr. Pruitt announced his intention to eliminate the 300-unit limit last year, claiming that the E.P.A. did not have the legal authority to force companies to significantly reduce production of glider trucks. The move was slowed down by the White House when it asked the E.P.A. to do a more comprehensive study of the environmental and economic impacts of the rollback.
Executives at Fitzgerald have not commented on the move. But in an opinion piece written in April, Tommy Fitzgerald Sr., its chief executive, praised Mr. Pruitt and blamed industry competitors, like Volvo, that sell new trucks for the now-delayed regulatory effort.
“The new truck industry conspired with the Obama EPA to try to put us out of business,” Mr. Fitzgerald wrote, adding, “Our goose was cooked until President Trump and Pruitt came to town.”