I'm pretty convinced Vingegaard didn't say what is being reported. It seems like a completely unprovoked own- goal and he's always very careful with what he says. Poor reporting probably.
But, unfortunately, there is little clarity on whether this method has been used/abused or not by Visma/UAE/ISP. I think there is a good chance. Pictures that occur of Visma riders doing the, now regulated, inhalation method is already out there.
Of course, the now illegal practice have only been provided to riders for "research purposes" but the researchers (Rønnestad and colleagues) do work/worked with Visma on training, heat and altitude optimization. If any team used/abuse it, it's surely Visma-LAB. I thought it was interesting to hear Patrick Broe defend Visma and other teams so forcefully on the LR podcast a while back. He really thought Escape collective had done an unfair hit-piece. Not sure they did.
Picture shows former Visma rider Staune-Mittet using the inhalation practice at a lab in Norway(?). It was published by Norwegian media in relation to the researchers doing a study on the, now banned, practice of administering regular doses of carbon monoxide. However, under the picture it say's that what we see here is just the legal measurement method. Thanks to
@Netserk for pointing this out