A West Virginia University research unit that helped expose Volkswagen AG's smog-test scandal was involved in another emissions test two decades ago that had similar results with polluting trucks.
The WVU Center for Alternative Fuels, Engines and Emissions was hired by the International Council on Clean Transportation to measure emissions on three cars.
According to the U.S. Environmental Protection Agency, the university found significantly higher emissions from two Volkswagens. WVU's findings prompted further testing by the EPA and the California Air Resources Board.
Volkswagen has acknowledged putting stealth software in millions of its vehicles worldwide.
In October 1998, after a WVU research team was hired for portable testing of heavy-duty diesel engines, the Justice Department announced that more than 1.1 million trucks were polluting much more than allowed. The manufacturers agreed to a $1 billion settlement.