The New York Times reported last week that US researchers in 2014 locked 10 monkeys into airtight chambers and made them breathe in diesel exhaust from a VW Beetle while the animals were watching TV cartoons. Separately, it emerged that a research group funded by VW, Mercedes-Benz parent Daimler and BMW had ordered a study in Germany measuring the effects of inhaling nitrogen dioxide on 25 human volunteers.
The scandal follows VW's admission in 2015 that it had manipulated 11 million diesel cars worldwide, equipping them with cheating software to make them seem less polluting than they were. Mueller on Monday labelled the animal testing "wrong ... unethical and repulsive", reported Spiegel Online.
And Steg had vowed in the top-selling Bild daily that "what happened should never have happened, I regret it very much". He admitted that he had been informed in advance of the US monkey experiment but insisted he prevented a plan to carry these tests out on humans.