"The culprits behind the criminal act are yet to be identified. Police have taken over investigation. It is a police case now and is no longer in our domain," chairman of the Atomic Energy Commission, S Banerjee told PTI.
"Somebody had mixed radioactive tritium in water cooler. It was a criminal act. It has nothing to do with the plant," he said.
On November 24, over 90 staff members of the nuclear power plant, comprising four units, were exposed to radioactive health hazards after the level of tritium, a radioactive isotope of hydrogen, was found to be 'unusually high' in their urine samples tested as a matter of routine.
Preliminary investigation revealed that tritium was mixed in the water cooler. Department of Atomic Energy, however, later clarified that none of the employees were adversely affected and the radioactive isotope was 'naturally cleansed from their bodies through urination.'