Thanks largely to the work of advocacy organizations to keep auto companies true to their word on environmental regulations, the world’s largest car manufacturer is in dire straits.

Since it was caught reporting fraudulent emissions data from its diesel vehicles, Volkswagen has lost more than a third of its market value, its CEO has departed, and it has pledged to recall up to 11 million vehicles to remove “cheat” software and replace it with hardware that will ensure the cars meet pollution emissions standards around the globe.

And now, organizations tied to the diesel industry are concerned that Volkswagen’s failures may soon affect their business.

Don’t Call It a Comeback (Yet)

Much has been written in recent years about diesel vehicles’ resurgence in the United States, due in part to increased fuel efficiency and a reduction in emissions that had long plagued the vehicles, particularly in American markets. General Motors, for example, recently delivered on its plans to expand its diesel offerings by adding diesel engines to several pickup models.

“The potential impact puts years of effort and millions of dollars of investments to waste,” AutoPacific’s Vice President of Industry Analysis Ed Kim told NBC News.

While declining to comment specifically about the Volkswagen scandal, the Diesel Technology Forum is looking to ensure that the current conversation doesn’t turn to condemning diesel fuel entirely.

“The circumstances involving a single manufacturer do not define an entire technology, or an industry,” the forum said in a statement.

“Nothing has changed the fact that the diesel engine is the most energy-efficient internal combustion engine,” it added.

Meanwhile, environmental regulators are amping up scrutiny of such claims. The new diesel-powered GM pickups will be the first passenger vehicles to be subjected to more extensive testing by the Environmental Protection Agency and the California Air Resources Board. And that testing will soon extend to every diesel vehicle in the country, even those that have already received a passing grade.

“Today we are putting vehicle manufacturers on notice,” Christopher Grundler, director of the Office of Transportation and Air Quality at the EPA, told reporters Friday.

(Voyagerix/ThinkStock)