According to the Utah Geological Survey, “Lung cancer fatalities caused by radon gas are Utah’s most deadly geologic hazard.”
“Between 1973 and 2015, there were approximately 5630 fatalities in Utah attributable to lung cancer caused by radon gas” Other possibilities:
- Volcanic eruptions
- Earthquakes
- Floods
https://geology.utah.gov/hazards/problem-soils/radon/