Three years after the Environmental Protection Agency began investigating alleged diesel emission cheating in Mercedes-Benz cars, vehicle owners and environmentalists say the Trump administration appears to be allowing the inquiry to stall.

Daimler AG, the German parent company for Mercedes, is among several automakers that have come under scrutiny since 2015 after Volkswagen admitted to equipping some of its diesel-powered cars with illegal software designed to hide excess emissions.

In 2016, federal and state regulators launched an investigation into whether Mercedes had used a similar cheat, enabling cars to pass emissions tests that they would have otherwise failed. German regulators also launched an inquiry.

In the intervening years, German regulators have found evidence of cheating by Daimler and hit the company with fines and forced recalls. However, in the United States there have been no repercussions as the investigation crosses the three-year mark.


“Three years seems unusual,” said John German, a former official at the EPA and a senior fellow at the International Council on Clean Transportation, the environmental advocacy group that commissioned the study that uncovered Volkswagen’s cheating. From start to finish, the government’s investigation into VW took about a year and a half, German said.

In April, consumer advocacy and environmental groups sent a letter to Congress asking that the investigation be expedited.

“It is past time for greater urgency and action from regulators and Congress on the allegations against Mercedes,” the advocates wrote. “Owners and lessees of Mercedes diesel vehicles have been left without answers or recourse while the illegally polluting vehicles remain on U.S. roads.”

The Trump administration has prosecuted one automaker for emissions cheating. In 2017, the Department of Justice sued Fiat Chrysler after an investigation found the Italian carmaker had used software to switch off emissions controls under certain driving conditions. The company agreed to pay $800 million to settle allegations that it had cheated on emissions tests involving 104,000 Jeep SUVs and Ram pickup trucks, including about 13,000 in California.


At the same time, the Trump administration has drafted plans to roll back rules restricting vehicle pollution. The EPA is expected to announce final plans this summer to freeze fuel-efficiency standards at about 37 miles per gallon, unraveling regulations put in place under the Obama administration that require automakers to meet a standard of 54.5 mpg.

The EPA projects that the administration’s plan would increase daily gas consumption in the U.S. by about 500,000 barrels a day, worsening greenhouse gas emissions and contributing to the rise in global temperatures.

American regulators’ inquiry into Daimler began in 2016 when the Department of Justice asked the company to conduct an internal investigation into its diesel exhaust emissions. Since then, the automaker has stopped selling diesel-powered passenger cars in the U.S.

“To me, that suggests that they had a problem and they’re trying to limit their exposure to that problem,” said German.


EPA officials declined to comment on the investigation, citing its ongoing investigation. The Department of Justice did not respond to a request for comment.

A spokesman for Daimler said the company continues to cooperate with American regulators, but would not discuss the investigation.

Though Daimler has denied wrongdoing, the company has recalled 3 million diesel-fueled vehicles in Europe. In June, German regulators ordered the company to recall 60,000 more and said they were widening their inquiry.

The German luxury brand is currently being sued in the U.S. by people who purchased Mercedes diesel cars. In a class-action lawsuit, lawyers representing Mercedes diesel owners said the cars were marketed as “the world’s cleanest and most advanced diesel.” But engineers hired by the plaintiffs found that they “emit far more pollution on the road than in the emission certification testing environment.”


According to the lawsuit, the cars produced average nitrogen oxide emissions, a smog-forming pollutant, that were 19 times higher than the U.S. standard. The complaint alleges that there are more than 200,000 diesel-powered Mercedes vehicles in the U.S.

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