Sometimes reality-television fame comes with some unforeseen side effects.
A certain subset of car enthusiasts enjoy modifying large diesel trucks, something that has gained wider public attention on the Discovery Channel show Diesel Brothers.
The show focuses on a Utah shop that specializes in these modified trucks.
But now a group of environmentally-minded Utah doctors plans to sue the show's stars, alleging that they made illegal modifications to vehicles' pollution-control systems.
Utah Physicians for a Healthy Environment (UPHE) informed the four men behind Diesel Brothers of its intention to file a lawsuit earlier this week, according to The Salt Lake Tribune.
UPHE claims to have found online videos in which the stars of Diesel Brothers demonstrate how to bypass a truck's emissions-control system, and advertise "repair kits" meant for that purpose.
Similar kits are available online, and are typically bought by owners looking to increase the performance of their diesel vehicles.
UPHE also claims to have been aware of other Utah shops performing similar work as far back as 2007, but is now specifically targeting the shop behind Diesel Brothers.
That business started out as DieselSellerz.com—a website that serves as a marketplace where users buy and sell modified diesel trucks, including ones built by the company's owners.
Most of the trucks displayed on the website and featured on the show are heavy-duty pickups from the Big Three Detroit automakers.
These types of modified trucks are often used for "rolling coal"—in which a truck is modified to discharge large plumes of black smoke.
UPHE has received many complaints about truck drivers rolling coal in its area of operation, Brian Moench—the group's president—told The Salt Lake Tribune.
Rolling coal theoretically constitutes a violation of the Clean Air Act, because it typically involves deliberately removing or modifying emissions-control equipment in such a way as to increase the amount of pollutants produced.
However, the heavy-duty trucks that most often get these modifications—and are most often featured on Diesel Brothers—aren't subject to the same regulations as passenger cars.
UPHE hopes to force the shop to cease its allegedly-illegal modifications, and would like to see the shop issue some sort of recall of its work as well.
This story originally appeared on GreenCarReports.