Between January 1, 2017 and March 16, 2018, PSP Diesel, LLC (PSP) violated Sections 203(a)(3)(A) and 203(a)(3)(B) of the Clean Air Act by removing and/or rendering inoperative the exhaust gas recirculation, diesel oxidation catalyst, diesel particulate filter, selective catalytic converter, and/or on-board diagnostics systems and selling, offering to sell, and/or installing parts and components where a principal effect of the part or component was to bypass, defeat, or render inoperative these emission controls and emission-related elements of design on heavy-duty diesel-engine trucks. EPA uncovered these violations through an inspection conducted on September 22, 2016 and a Request for Information issued under Section 208 of the Clean Air Act on March 8, 2018, to which PSP responded on July 10, 2018. EPA issued a Finding of Violation to PSP on September 28, 2018. PSP confirmed that it is no longer removing, disabling, or bypassing any emission control system or element of design on any vehicle. PSP certified that as of May 31, 2019, it has not had, and will not have, any defeat device(s) in its inventory and/or possession. PSP has agreed to pay a penalty of $30,736 to settle this action. These violations resulted in approximately 53 tons of excess annual nitrogen oxide emissions and 1.3 tons of excess annual particulate matter emissions.