The Japan Atomic Energy Agency said that five workers at a research facility in east Japan had been exposed to high levels of radioactivity after a storage bag they were handling burst open. The agency said radioactivity measured in the lungs of the workers ranged from 2,000 to 14,000 becquerels in four of the workers and up to 22,000 becquerels in the fifth worker's lungs.
No radioactive material escaped from the “controlled” room where the incident took place, the JAEA said in a statement.
One JAEA spokesperson did not define the material source of the incident, declining to say whether or not plutonium was involved. Another, who declined to be named, said plutonium was the source involved in the incident, according to a Reuters report.