Multinational automotive manufacturer Volkswagen on Tuesday suspended its chief lobbyist Thomas Steg following reports that the company had sponsored experiments that exposed humans and monkeys to diesel exhaust.

In a report on January 25, The New York Times said that car makers Volkswagen, BMW and Daimler had funded the European Research Group on Environment and Health in the Transport Sector to commission the tests. During the tests that were carried out in May 2015, 10 Java monkeys were locked in small air-tight chambers for four hours at a time, and left to watch cartoons as they breathed in diesel fumes. German newspapers also reported that another study funded by these carmakers had exposed 25 human volunteers to nitrogen dioxide.

“At its meeting today, the board of management accepted the proposal made by Thomas Steg, head of group external relations and sustainability, that he be suspended,” Volkswagen said on Tuesday. Jens Hanefeld, who is responsible for International and European Policy, will take over.

“Thomas Steg is a general representative of the Volkswagen Group and will remain suspended from his duties until these matters have been fully investigated,” the statement added.

Chief Executive Officer Matthias Müller said, “We are currently in the process of investigating the work of the EUGT, which was dissolved in 2017, and drawing all the necessary consequences.” On Monday, Müller had said, “Over the weekend we had to learn once more that there is still a long way ahead of us to regain lost trust,” according to Reuters. “The methods used by EUGT in the United States were wrong, they were unethical and repulsive.”

These reports come nearly two years after the carmaker admitted that it cheated diesel emission tests in the United States. The German automaker had fitted as many as six lakh cars in the US with a software to fool emissions tests. Investigators said the cars emitted more than 40 times the legal limit of nitrogen oxide.