What kind of illness in town worries Dan and who seems to have it?

Dan is anxious about three cases of radiation poisoning. He cannot determine the source since fallout would expose many more than three. These patients have burned hands and expected symptoms of nausea, headache, diarrhea and hair loss. Randy suggests Porky Logan was in south Florida on The Day and got radiation there. Dan says he was okay when he returned and gets no more exposure than any one else since then but still gets worse. Bill Cullen and Pete Hernandez have similar symptoms.