Yeah, I mean if the stove is in good condition it only releases anything when it’s first turned on before it fully ignites and possibly a miniscule amount when it turns off, but yeah, it’s not a bad idea to vent during that time or if you have a stove that’s in bad condition or is dirty and not directing the gas properly so it fully burns. Same for water heaters, though, and older furnaces, though modern ones deal with it.

But either way it’s a tiny bit and on its own is not likely to cause problems. The problem is that we get exposed to so many other carcinogens that it all adds up, so any exposure that you can limit is a good thing. And of course, risk increases with age.