Two Los Angeles-area men pleaded guilty this week to violating the Clean Air Act by conducting scores of fraudulent smog check inspections.

Jermaine Elroy “Aria” Williams and Darnell Tyrone Usher each entered their pleas to a federal conspiracy count and are scheduled to be sentenced in federal court on June 5. The charge carries a possible penalty of up to five years in prison, prosecutors said.

Both men were charged a year ago in a 44-count indictment that focused on Smogz R Us, a shop that operated on West 54th Street in South Los Angeles.

Williams and Usher—along with seven others—were charged with conspiracy and various counts of making false statements in connection with more than 1,300 bogus smog checks conducted at the location.

According to the indictment, the defendants engaged in a form of fraudulent smog testing in which vehicle identification information was entered into smog testing equipment to make it appear that a particular vehicle was being tested—while a substitute “clean” vehicle was tested in order to obtain a passing grade.

Once the bogus tests were completed, the defendants submitted phony Certificates of Compliance to California’s Vehicle Information Database, falsely certifying that vehicles passed the emissions checks when they were never tested, prosecutors said.

Williams, 33, of Woodland Hills and 27-year-old Usher, of South Los Angeles had previously been banned by a Los Angeles Superior Court judge from working in the smog or emissions industry, according to federal prosecutors.

Part of the federal Clean Air Act prohibits a person from knowingly making false statements and certifications in relation to the smog check program.