>>2139752If the water coming out of the mine is deep/rich blue or other unusual colors, if there are dead bats on the ground, if you feel "loose" or giddy, if simple tasks are more difficult, if there are any funny smells, if you can physically see a haze at boot level. There are probably way more; I'm not familiar with trapped gas pockets all that much and I'm just an environmental nerd that only explores as very sporadic hobby.
