This mod adds 2 things: oxygen tank that can be equipped in back curios slot and vent, that fills hermetic area with oxygen. Both of them uses liquid oxygen from mekanism.
To make dimension unbreathable add it to config.
Feel free to use in your modpacks.
If you are looking for a config for Starlance use this:
unbreathableDimensions = ["cosmos:alpha_system", "cosmos:b_1400_centauri", "cosmos:earth_moon", "cosmos:europa_lands", "cosmos:gaia_bh_1", "cosmos:glacio_lands", "cosmos:jupiterlands", "cosmos:j_1407blands", "cosmos:j_1900", "cosmos:marslands", "cosmos:mercury_wasteland", "cosmos:neptune_lands", "cosmos:plutowastelands", "cosmos:saturn_lands", "cosmos:solar_system", "cosmos:uranus_lands", "cosmos:venuslands"]
