Hypoxia appears to be the correct term for oxygen starvation which can be caused by a Natural Gas or Carbon Monoxide leak. Sometimes fatal.

In my wife's case when she was exposed to natural gas and carbon monoxide on Sunday from a gas leak combined with incomplete combustion, her symptom was a headache. However, she was not familiar with the smell of natural gas like I was from dealing with building houses and such growing up. I also recognized the smell of carbon monoxide which in lower doses smells a little like Car exhaust which can be fatal too in some situations

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Hypoxia occurs when oxygen is insufficient at the tissue level to maintain adequate homeostasis, stemming from various causes such as hypoventilation, ventilation-perfusion mismatch, or right-to-left shunting. Hypoxia can manifest acutely or chronically, with varying presentations from dyspnea to tachypnea.Mar 4, 2024

Hypoxia - StatPearls - NCBI Bookshelf

National Institutes of Health (NIH) (.gov)

https://www.ncbi.nlm.nih.gov › books › NBK482316