Here is an article about 4 men that died next to a waste rock pile in BC, Canada, from lack of oxygen. Another problem is almost all health and safety sensors u

Here is an article about 4 men that died next to a waste rock pile in BC, Canada, from lack of oxygen. Another problem is almost all health and safety sensors use oxygen as a baseline for testing, so in a lack of oxygen they do not work accurately. So even experts can get caught in such an extreme situation. https://www.cbc.ca/news/canada/british-columbia/lack-of-oxygen-killed-4-at-b-c-mine-report-1.582325 https://www.cbc.ca/news/canada/british-columbia/lack-of-oxyg...