WASHINGTON • The Obama administration has directed Volkswagen to recall nearly half a million cars, saying the automaker illegally installed software in its diesel-powered cars to evade standards for reducing smog.
The Environmental Protection Agency (EPA) accused the German automaker last Friday of using software to detect when the car is undergoing its periodic state emission testing. Only during such tests are the cars' full emission control systems turned on.
During normal driving situations, the controls are turned off, allowing the cars to spew as much as 40 times the pollution allowed under the Clean Air Act, the EPA said.
"We expected better from Volkswagen," said Ms Cynthia Giles, the EPA's assistant administrator for the Office of Enforcement and Compliance. She called the automaker's actions "a threat to public health".
Agency officials issued the car company a notice of violation and said it had admitted to the use of a defeat device. The recall involves four-cylinder Volkswagen and Audi vehicles from model years 2009 to this year.
A spokesman for Volkswagen confirmed that the company had received the notice and said the automaker was cooperating with the investigation. She declined to comment further on the case.
The software was designed to conceal the cars' emission of the pollutant nitrogen oxide, which contributes to the creation of ozone and smog. The pollutants are linked to a range of health problems, including asthma attacks, other respiratory diseases and premature death.
Experts in automotive technology said that disengaging the pollution controls on a diesel-fuelled car can yield better performance, including increased torque and acceleration. "When the pollution controls are functioning on these vehicles, there's a trade-off between performance and emissions," said Mr Drew Kodjak, executive director of the International Council on Clean Transportation, a research group. "This is cutting corners."
It was Mr Kodjak's group, in conducting research on diesel vehicles, that first noticed the discrepancy between Volkswagen's emissions in testing laboratories and on the road. They brought the issue to the attention of the EPA, which conducted further tests on the cars, and ultimately discovered the use of the defeat device software.
California has issued a separate notice of violation to the company. California, the EPA and the Justice Department are working together on an investigation of the allegations. Over the next year, EPA officials said that owners of the affected vehicles should expect to receive recall notices from the company, including information about how to get their cars repaired at no cost to them.
The recall covers roughly 482,000 diesel passenger cars sold in the United States since 2009.
Last Friday's notice of violation was the Obama administration's "opening salvo" in the Volkswagen case, said Mr Thomas Reynolds, an EPA spokesman. The Justice Department's investigation could ultimately result in fines or penalties for the company.
Under the terms of the Clean Air Act, the Justice Department could impose fines of as much as US$37,500 (S$52,200) for each recalled vehicle, for a possible total penalty of as much as US$18 billion.
NEW YORK TIMES