Medium- and heavy-duty trucks aren't used for racing very often.
But that hasn't stopped an aftermarket-industry group from using recently-passed emissions standards for large trucks to lobby for legislation covering cars that are modified and raced.
The Specialty Equipment Marketing Association (SEMA) is probably best known for the massive trade show it puts on in Las Vegas every year.
SEMA also has a lobbying arm, though, which created an uproar earlier this year after draft EPA language allegedly prohibiting modifications to emissions equipment on race cars came to light.
That language was quickly removed after a SEMA-stoked public outcry, but the organization is still pursuing the matter, according to Hemmings Daily.
The controversial language was interpreted as saying that all stock emissions equipment would have to be retained in cars, even if they were used in competition.
SEMA interpreted the draft EPA language as essentially prohibiting street cars from being modified for racing.
In turn, car modifiers and racing enthusiasts saw a potential threat to their businesses and hobbies.
The existing regulations the EPA referred to already prohibit tampering with or removing emissions equipment, and don't explicitly say that car modifiers are exempt from the fines levied for violations.
SEMA and its supporters have pointed to committee notes from the drafting of the 1970 Clean Air Act that appear to support an exemption for racing vehicles.
The EPA subsequently claimed the language of the earlier rules was simply meant to clarify existing regulations about tampering with or removing emissions equipment—and then the agency removed it from the draft regulations altogether.
A statement in the final regulations also noted that the EPA "supports motorsports and its contributions to the American economy and communities all across the country."
The agency said that its focus "is not (nor has it ever been) on vehicles built or used exclusively for racing," but rather companies that sell illegal "defeat devices" meant to bypass emissions equipment that can be used on road vehicles.
Some of those companies, of course, are part of the aftermarket industry that SEMA represents.
SEMA officials have not commented on the finalized version of the regulations that previously included the controversial car-modification language.
But they have continued to push elected officials to support the Recognizing the Protection of Motorsports Act of 2016, twin bills currently pending in the House and Senate.
Also known as the RPM Act, the legislation seeks to "exclude vehicles used solely for competition from certain provisions of the Clean Air Act," according to the text of the House bill.
Both bills were introduced in March and remain in committee.