I'm pretty sure the issue with carbon monoxide poisoning is that you don't actually feel it clearly enough and that it doesn't manifest as "can hardly breathe".

"Gases such as ammonia and chlorine are ir- ritating to the skin, eyes, and throat and have a very definite smell. CO, however, has no odor or other warning properties." [1]

1- https://www.msha.gov/sites/default/files/Alerts%20and%20Haza...

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eviks 6 days ago | parent [-]

I'm pretty sure your own link is consistent

> Medium exposure... will produce ... and breathing difficulties.

	▲	rkomorn 6 days ago \| parent [-]
		I think the difference comes down to prolonged exposure to lower levels (eg medium exposure) vs short-term exposure to high levels. The canary is for the latter scenario. If the EPA says it can kill "in minutes" [1], then I'd be inclined to believe them over "you'll feel it if you're exposed to it for hours". 1- https://www.epa.gov/indoor-air-quality-iaq/protect-your-fami...