Around 1959 my uncle Eddie built a really nice bomb shelter in his basement. People were doing that in those days. He had a party to celebrate the completion and show off the reinforced walls and supplies of food and water. He was definitely prepped.
He was a heavy smoker. One day he collapsed at home and was dead of lung cancer a few months later. His wife, also a heavy smoker, died of lung cancer a few years later. So did his brother, my dad.
It's really hard to know what the real dangers are.
Mitch_I