The EPA and the Justice Department announced today that Kia Motors and Hyundai Motor would be fined a collective $100 million for allegedly violating the Clean Air Act. This fine is in addition to being tasked with spending $50 million on efforts to prevent further violations and giving up 4.75 million greenhouse gas admission credits, worth over $200 million. These credits are gained by building cars with lower emissions than required, according to an EPA news release.

The cars involved in this settlement were the Hyundai Accent, Elantra, Veloster and Santa Fe, and the Kia Rio and Soul. The news release notes that between model years 2012 and 2013 the companies sold 1.2 million units that did not meet the specifications the company certified to the EPA, understating both fuel economy and greenhouse gas admissions.

Around $93 million of the civil penalty will go to the US government, with the remainder being paid to the California Air Resources Board.

In an e-mail, Hyundai representative Chris Hosford said that the company believes this was “an honest mistake” and that the EPA rules suffered from a “lack of clarity.”

According to CNBC, Hyundai will pay $56.8 million of the fine, with Kia paying the rest.

Hyundai will be forfeiting 2.7 million credits, while Kia is giving up 2.1 million.