Part of the problem was that because authorities waited days to begin the evacuation of Prypyat, the entire town and everyone and everything in it were highly contaminated, and they exported that contamination all over the Country on cars, people, furniture, you name it. The roads leading in and out were heavily contaminated as were the tires on any vehicle that drove on them.
Just a nightmare scenario, and the cleanup still goes on today.
My sister once monitored film badges / dosimeters for a military site. A day or two after Chernobyl, the background radiation counts had skyrocketed here, half a word away.