[JayJay]

Not meaning to start a political discussion, but many years ago city and county animal control shelters used CO from motor vehicle engines for euthanasia. On one of my oddball engineering consulting jobs early in my career I got called out to a shelter that found that their euthanasia chamber wasn't working. It had a WWII surplus jeep engine mounted on a frame, and piped the exhaust from it to the chamber. Turns out that a couple of weeks before the engine wouldn't start, and the shelter called out their motor pool mechanics to fix it. They rebuilt the engine and tuned that engine up so sweet that it wasn't emitting enough CO to put the animals down. I suggested that they adjust the mixture to way rich, and behold, it worked just like before.