At a house hearing on Thursday, U.S. Lawmakers attacked federal environmental regulators for not being able to catch Volkswagen’s emissions control fraud.

According to Reuters, Texas Republican representative Michael Burgess slammed the U.S. Environmental Protection Agency (EPA) and pointed out that the West Virginia University study, which had discovered the defect, had a much lower budget than the organisation.

"I'm not going to blame our budget for the fact that we missed this cheating," responded Christopher Grundler, the director of the Office of Transportation and Air Quality (OTAQ) for the E.P.A. He added that Volkswagen was due to provide options to uninstall the cheat device by early next week.

The news comes just after Volkswagen’s American unit’s head Michael Horn revealed that a second software had been installed in its diesel-powered cars. "This was a couple of software engineers who put this in for whatever reason," Horn said under oath.

Since Volkswagen was discovered using illegal software to evade emissions tests, its shares have plummeted to low levels and more than a third of the company's market value has been swept away.

The German carmaker has used two separate cheat devices in the United States and Europe because the regions have a different set of emissions standards, confirmed Horn. "Some people have made the wrong decisions in order to get away with something," he added.

Amid escalating tensions as a result of the internal investigation, Volkswagen is set to suspend 10 senior managers. German prosecutors also raided Volkswagen's headquarters and other offices earlier on Thursday in a bid to find out whether it has cheated Europe’s emissions testing.

The internal inquiry revealed that some engineers installed the software because they realised that the engines would fail to comply with emission standards. However, company investigators have not found any evidence against the engineers.

Contact the writer at feedback@ibtimes.com.au, or let us know what you think below.

RELATED STORIES