Two workers from Japan's stricken Fukushima nuclear plant have been contaminated by high levels of radioactive iodine, the operator said Monday, prompting fears over their long-term health.
The workers, reportedly men in their 30s and 40s, may have already been exposed to radiation levels higher than the recently boosted official annual limit, Japanese media suggested.
Tokyo Electric Power Company (TEPCO) said it had been measuring the internal exposure to radiation of all employees involved in emergency work at the Fukushima Daiichi plant crippled by the March 11 earthquake and tsunami.
Internal exposure occurs when people take radioactive substances into their bodies through tainted air or food and drink.
The company notified the governmental atomic energy agency of the possible problem and the agency confirmed that "the thyroid glands of two male employees showed high levels of radiation (iodine-131)", TEPCO said in a statement.
The Jiji Press news agency said the two workers had stopped working at the plant and were not sick at the moment. They will undergo further check-ups.
The inspection by the government agency found 9,760 and 7,690 becquerels of iodine-131 in the thyroid glands of the workers, 10 times higher than other workers at Fukushima, reports said.
The two men were working at a variety of locations at Fukushima Daiichi, including the central control room, in March and April, including on March 11 and during the following days.
The tests sparked fears that their radiation exposure had been several hundred millisieverts, Jiji said.
A few days after the disaster, the government boosted the annual limit of radiation exposure for emergency workers to 250 millisieverts from 100 as the nation battled the world's worst nuclear crisis since Chernobyl in 1986.
No workers have been confirmed to have been exposed radiation higher than the annual limit since the disaster.
Radioactive iodine is known to accumulate in the thyroid gland.