Generally kept lower than that. Exceeding the human exposure threshold for a worker amounts to an international nuclear incident. Literally. Must be reported

Generally kept lower than that. Exceeding the human exposure threshold for a worker amounts to an international nuclear incident. Literally. Must be reported and the IAEA will do a full investigation and eventually assign it an International Nuclear Event Scale number. (7 = Chernobyl. 2 = Worker dropped a small vial of tritium gas and breathed it in.)