OARAI, Ibaraki -- A worker at a research and development (R&D) center here has been found to have a high level of radioactive material -- up to 22,000 becquerels -- in his lungs following exposure to radiation, the center said on June 7.
The discovery came after five workers at the Oarai Research & Development Center, which belongs to the Japan Atomic Energy Agency, were exposed to radioactive materials on June 6.
Radioactive materials are difficult to expunge from the human body, and it is thought that the level of internal exposure in this case will be 1.2 sieverts in one year, and 12 sieverts over 50 years.
The five workers have been taken to the National Institutes of Radiological Sciences in Chiba Prefecture, where they are undergoing examinations.
At a Nuclear Regulation Authority (NRA) meeting on June 7, a committee member said the workers' situation is "not mild."
According to organizations such as the NRA, one of the five workers was found to have up to 22,000 becquerels of plutonium-239 and 220 becquerels of americium-241 in his lungs. Two other workers were discovered to have 12 becquerels and 130 becquerels of americium-241 in their lungs, respectively. All five workers were administered medicine designed to reduce the radiation dose of the internal exposure.
The five workers were all wearing protective clothing and face masks at the time of the radiation exposure, the R&D center said. It is currently being investigated whether or not there were any problems at the time the incident happened.
Plutonium and americium are both harmful to human bodies as they emit alpha rays.