Monkeys were used in test labs to measure tolerance to diesel emissions, says the New York Times.
It reported a Mexican laboratory had been using the animals to support research by a European body looking at health in the transport sector on behalf of some German car makers, but the companies have distanced themselves from the lab tests using monkeys and said they would not condone such tests as those carried out in 2014.
They have also reportedly wanted an explanation as to why the tests involved the animals but the European body commissioning the tests went out of business so the management of the car companies involved are likely to look to their own executives for explanations.
Questions are also being raised about why the potentially controversial lab tests were carried out in Mexico but applied on behalf of European car makers concerned over Continental emissions programmes rather than under the closely monitored regimes in place in European laboratories closer to the car makers’ bases and where they are likely to have been picked up sooner by animal rights activists.
Volkswagen has apologised for the tests being conducted on its behalf and said they were inappropriate. Daimler and BMW have not publically responded.