Considering that the deaths from fentanyl, alone, in the US are over 60,000 per year, while the total number of documented deaths due to radioactive incidents is well under 1000, the podcast is on safe grounds making that statement.
I think this is something that really needs more publicity. When I was younger street drugs were stupid, but generally speaking not lethally so. Now anytime you take an illicit substance you're risking a fentanyl OD.