Volkswagen (VW) on Tuesday added 800,000 additional vehicles to its list of models affected by emissions irregularities.

VW previously admitted that up to 11 million diesel vehicles were equipped with software that allowed them to pass emissions tests by temporarily lowering pollution levels, only to turn this software off during normal operation. VW has now admitted that 800,000 more vehicles have emissions issues that need to be addressed, CNet reports.

VW's emissions scandal began in September, causing the company's stock price to plunge. On Wednesday, VW said that fixing the newest round of vehicles could cost the company an additional $2.2 billion. The announcement sent the company's stock price down by another 8.4 percent.

The company's reputation has also suffered due to the scandal. VW was forced to issue a massive recall of about 8.5 million vehicles, and the company will likely face lawsuits.

"From the very start I have pushed hard for the relentless and comprehensive clarification of events," Volkswagen CEO Matthias Müller said in a statement. "This is a painful process, but it is our only alternative. For us, the only thing that counts is the truth."

VW went public with the additional 800,000 vehicles after the Environmental Protection Agency (EPA) made new allegations against the German car company on Monday. The EPA found "defeat devices" designed to trick emissions tests on some of VW's large sport utility vehicles powered by diesel. The EPA tested these vehicles and found that they pollute up to nine times more than what is allowed.

Volkswagen appears very concerned about all of the issues revealed by the emissions scandal. The company says they are committed to making things right and earning back the trust of customers.

Besides the VW brand, vehicles made by Porsche, Audi and Skoda are also part of the massive recall.