Re: It's probably gas...
Methane isn't considered to be toxic although there might be times when one would wish it were. Methane-Oxygen mixtures from 5-14% are explosive though.
The rather infamous SpaceX toilet is, it would seem, still busted. Astronauts will be issued high tech "underwear" which is -- I suspect -- Newspeak for "diapers". No, I am not making that up. https://fuentitech.com/spacex-toilet-issues-make-astronauts-dependent-on-underwear-silicon-valley/328181/
Biting the hand that feeds IT
