NEW DELHI: The Atomic Energy Commission (AEC) on Sunday confirmed that radioactive tritium was deliberately put in a water cooler at the high-security Kaiga Nuclear Power Plant, in Karnataka, exposing about 50 workers to increased level of radiation.Minister for science and technology Prithviraj Chavan confirmed that the Kaiga incident was an act of sabotage and added that the Centre will order a probe into what looks like an insider job.“The Kaiga incident is an act by a disgruntled employee. He mixed a small unit of tritium (radioactive isotope of hydrogen, D20), in a water cooler. All those who drank water from the particular cooler showed a high level of radiation effects,” he told reporters.Though prima-facie it appeared to be the work of an employee who was trying to grab media attention, the government will initiate a high-level inquiry into the episode and probe the influence of “other elements” on employees. The minister also said he had spoken to Atomic Energy Commission chief Anil Kakodkar, who has also maintained that the contamination was an insider job.“Somebody deliberately put the tritiated water vials into a drinking water cooler. Therefore, we are investigating who is behind the malevolent act,” Mr Kakodkar said.He said investigations were being carried out to ascertain who contaminated the water cooler with tritiated heavy water and probe from the radiation protection angle was also being done.The Nuclear Power Corporation of India Ltd (NPCIL) has already ordered a probe into how a drinking water cooler in a highly restricted zone was contaminated with tritium.“Preliminary enquiry does not reveal any violation of operating procedures or radioactivity releases or security breach. It is possibly an act of mischief,” NPCIL chairman and managing director S K Jain said in a statement. He expressed concern over the radioactive contamination of the water cooler located outside the reactor building.Kaiga Nuclear Plant station director J P Gupta was quoted by a news agency as saying that around 50 employees were subjected to treatment on November 25 to quickly reduce tritium dosage in their bodies, after they drank water from the cooler.However, he said tritium was not poisonous and its presence in the body would come down on its own. He said that the incident has been reported to the intelligence department. “A committee has been formed.” Nuclear scientists are in the committee.