It might have just been CO2 accumulation they were worried about. CO2 is heavier than N2 so it pools at the bottom of places like that and you wouldn’t know until it was too late.
Fun Fact - Your body cannot sense when air doesn’t contain enough oxygen to keep you alive. However it can sense when there is too much CO2 and causes you to panic.
It might have just been CO2 accumulation they were worried about. CO2 is heavier than N2 so it pools at the bottom of places like that and you wouldn’t know until it was too late.
actually i think the body has receptors for CO2? not for CO though. like CO2-rich air outright smells sour.
Fun Fact - Your body cannot sense when air doesn’t contain enough oxygen to keep you alive. However it can sense when there is too much CO2 and causes you to panic.