Preppers/survival

I do my own building, construction and renovation ... did some commercial work but never enough to want to do it for a living ... I know enough to do my own but not enough to call myself a pro.

From what I've learned about underground building is that it is very dangerous and a health hazard. You have to constantly monitor and create safety measures for gases and oxygen levels. Even with the best setups ... actually with super sealed setups ... it can be very dangerous without active monitoring. Carbon dioxide, monoxide, and many gases will naturally want to drift to lower levels and displace oxygen which wants to move up ... if you happen to be unlucky to have a generator or car running next to your exit/entry hole ... your underground space quickly loses oxygen and without monitoring equipment or alarms, you just get dizzy, fall asleep and die .... very gentle death because you will never know what happened.

There was a news story a year or two ago ... in Australia I think? .. of a farmer that crawled into an underground reservoir that was empty to repair it ... his generator or vehicle was running nearby and he lost consciousness inside and died ... it's actually a common enough occurrence for farmers and industrial workers and construction workers

Anyone who is even thinking of building anything underground has to know and understand this dangerous fact