Two TEPCO workers at the crippled Fukushima No. 1 nuclear power plant were exposed to levels of radiation exceeding standards established by the government.
Two TEPCO workers at the crippled Fukushima No. 1 nuclear power plant were exposed to levels of radiation exceeding standards established by the government.
In the worst case, one of the workers may have been exposed to 650 millisieverts, more than double the upper limit of 250 millisieverts established by the government for workers dealing with the nuclear accident.
Tokyo Electric Power Co. officials on June 3 announced the results of a study conducted by the National Institute of Radiological Sciences.
One of the employees is in his 30s while the other is in his 40s. Since the Great East Japan Earthquake struck March 11, the two have been working at either the central control room in a reactor or the building away from the reactors where work is overseen during emergencies.
The study estimated that the man in his 30s has been exposed to internal radiation at levels between 210 and 580 millisieverts while the man in his 40s has been exposed to levels between 200 and 570 millisieverts.
The man in his 30s was found to have been exposed externally to 73.71 millisieverts while the man in his 40s was exposed externally to 88.70 millisieverts.
Combining the internal and external exposure levels would mean that both men had been exposed to more the 250 millisieverts.
Health Ministry officials will conduct an investigation at TEPCO offices and issue recommendations to improve worker safety.
The two men took stable iodine agents March 13 to prevent radioactive iodine from accumulating in the thyroid gland. However, after taking two pills that day, neither took the pills again.
Because an extended period of working under exposure to high levels of radiation was never envisioned, it was not until March 19 that the Nuclear Safety Commission of Japan asked workers to continually take the iodine agents.
According to ministry officials, by then there were 130 TEPCO workers engaged in work similar to that of the two men found to have been exposed to radiation.
A study by TEPCO found 52 workers with radiation exposure internally of levels exceeding 20 millisieverts. Of those individuals, three were exposed to radiation levels exceeding 100 millisieverts.