In a facility that treats toxic wastes, a 750-litre container of waste from an infectious disease ward at a cancer research institute lit up a radioactive detection frame. The radioactive element may have been technetium-99 (with 6-hour periodicity). These wastes may have originated from a patient receiving treatment at the institute in nuclear medicine. Once 60 hours had elapsed, tank contents could be incinerated provided measurements confirmed a decreasing trend. With the approval of a certified radioprotection institute, the container was stored inside a confined building. Two slightly exposed individuals were tested: their exams returned a negative result.