On March 3, 2026, the U.S. District Court for the District of Connecticut granted the government's motion for default judgment against Street Diesel Performance ( SDP ). The complaint alleged that SDP violated the defeat device prohibition of Title II of the CAA at Section 203(a)(3)(B), 42 U.S.C. Section 7522(a)(3)(B). This provision prohibits any person from manufacturing, selling, offering to sell, or installing parts or components whose principal effect is to bypass, defeat, or render inoperative a motor vehicle emission control device or element of design, where the person knows or should know that the part is being offered for sale or installed for such use. EPA alleged that SDP sold no fewer than 456 aftermarket defeat devices. SDP is a small Connecticut business that offers for sale via its website automotive parts and accessories, including but not limited to aftermarket automotive exhaust parts designed to remove or disable emission control systems on medium- to heavy-duty diesel pick-up trucks. The court imposed the government's requested $500,000 civil penalty and permanent injunction prohibiting SDP from selling or offering to sell defeat devices.
On January 25, 2024, Region 1 referred a Clean Air Act matter to the Department of Justice for enforcement. Through its website, SDP LLC d/b/a Street Diesel Performance (SDP) offers for sale various diesel-related vehicle parts from its facility in Chaplin, Connecticut. The referral alleges that SDP's sales