Visitors stand around cars during the Volkswagen group night ahead of the Frankfurt Motor Show (IAA) in Frankfurt, Germany, September 14, 2015. Reuters/Kai Pfaffenbach

The U.S. government has asked Volkswagen to withdraw nearly half a million cars and fined the company up US$18 billion (AU$25.03 billion) after the Environmental Protection Agency found out that the company has been using illegal software in its diesel-powered cars to deceive emissions testing.

The EPA has accused the company of using software that detects emissions testing when the cars’ full emissions control systems is turned on while the controls remain turned off when the cars are being normally driven. This allows emission of large quantities of pollution rapidly. EPA estimated that the cars belch 40 times greater pollution than mentioned in Clean Air Act. The pollutants are capable of causing serious health problems, including asthma attacks, other respiratory diseases and premature death.

Failing to comply with federal clean air rules, the company has been directed to pay up $37,500 (AU$52148.63) for each car, reported Reuters. However, Volkswagen is not alone in this allegation; Audi diesel cars have been also involved. As many as 48,000 four cylinder Volkswagen and Audi diesel vehicles produced between 2009 and 2015 could be recalled.

EPA’s enforcement officer Cynthia Giles said that this was beyond expectations, citing the act as a threat to human health. The company has been sent a letter of warning and has admitted to the use of illegal software. One of the spokespersons from Volkswagen has said that the company was doing what it could do best in the investigation and did not make further comments.

“When the pollution controls are functioning on these vehicles, there’s a trade-off between performance and emissions,” said Drew Kodjak, executive director of the International Council on Clean Transportation, a research group. Currently, EPA hasn’t acted on the recall which could take up to a year to get processed, depending on the complexity of the issue.

Meanwhile, California has issued a separate notice of breach of safety standards to the company. California government is working with EPA and the Justice Department on the investigation. According to EPA officials, the owners of the cars are soon to get recall notices and will also be provided with the information of getting the cars repaired without any cost.

Affected diesel models include the 2009-15 Volkswagen Jetta , Beetle, Audi A3 and Golf cars sold between 2008 and 2015 in the U.S., and Passat cars sold from 2014 to 2015.

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