Why would you think that methane is toxic? I know the average american knows nothing about even 6th grade chemistry but these kind of comment pop up on every thread about rockets.
Ah, yes, as we all know, Americans are unique in the entire world for their lack of knowledge of chemistry.
It seems that the toxicity of methane should be discussed not alone, but rather with respect to the partial pressure of oxygen in the atmosphere in question.
https://www.ncbi.nlm.nih.gov/books/NBK208285/#:~:text=Thus%2....
https://en.wikipedia.org/wiki/Atmosphere_of_Earth:
“As of 2023, by mole fraction (i.e., by number of molecules), dry air contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases.”
Did they take out nitrogen, added 7 parts nitrogen to 10 parts of air, use something else than mole fraction, …?