I watched a documentary recently which interviewed one of the official photographers who covered the cleanup. He went out on the roof with one of the teams shovelling debris back into the reactor building (they wore lead-lined protective clothing and were only allowed out for a few seconds - it was pretty much a case of one shovel load over the edge, then run for it). When he came to develop his film he noticed that it had marks at the bottom of the frame, caused by the radioactive wreckage he'd been walking amidst.
Originally Posted by Aron
Given that these lenses don't appear to fog film I wouldn't worry unduly. The natural background radiation in some areas will be higher.