From this article on the Iron Mountain storage facility.
'In the sixties and early seventies, Mesick said, people sometimes slept
in the mine: it contained fallout shelters, built and maintained by Iron
Mountain for executives from Exxon, Shell, and other big companies.
especially elaborate shelter, he said, had sixty-five hotel rooms, each
with a private bath, and a large cafeteria with a commercial kitchen;
in the mid-century-modern bedrooms, curtains obscured the concrete.
According to Mesick, in the event of nuclear war, some executives, along
with their families, would have been evacuated by helicopter from New
York City. “They’d hired local folks to tend to them, to cook for them,
to clean for them,” Mesick told me. “Their idea was to wait out the
storm while the debris and radioactivity were going on overhead—then
they were going to come out and sell oil to everyone who was left.”
Every now and then, Mesick recalled, the executives would run a “live
exercise”—essentially, they’d come and hang out for the weekend.'
It's good to know that the really important people would have been safe.