you are correct Susan but there are clarifiers. The different kinds of radiaton are:
Alpha: 1-3" rng/stopped by paper
Beta: 10-30' rng/stopped by tight woven clothing
Gamma: several 100 yds rng/14 half-life shield thicknesses (by my calculations)
Neutron: 30 miles?/28 half-life thicknesses (by my calculations)
Most of the "bad" radioactive elements will be dead (isotopes) by the time they fall back to earth. Radioactive levels decay "on a bell curve"
It is not the TEOTW as the no-nuke kooks make it out to be.