WASHINGTON - U.S. government sensors are detecting traces of radiation believed to be from Japan's stricken nuclear plant, but they remain far below levels considered dangerous to people, the Environmental Protection Agency said on Monday.
The EPA said 12 air monitoring locations across the country have identified trace amounts of radioactive isotopes believed to have come from Japan's crippled Fukushima nuclear plant hit by an earthquake and tsunami on March 11.
Some of the readings were slightly higher than similar ones picked up last week, but were still tiny compared with radiation coming from natural sources, the EPA said.
"These types of findings are to be expected in the coming days and are still far below levels of public health concern," the EPA said in a release.
Radiation at the Fukushima plant poses a threat to workers, but Japanese officials and international experts have said radiation levels away from the plant are not dangerous to people, who in any case face higher doses from sources like X-rays and flying.
The EPA has more than 100 fixed monitors that measure air radiation levels in 48 states. It deployed additional air monitors to Hawaii, Alaska, Guam, and the Northern Mariana Islands after the disaster in Japan.
Last week the EPA said "minuscule" amounts of radiation consistent with a release from the damaged Fukushima plant were detected in Sacramento, California. But those were lower than levels that people get from various sources including natural radiation from certain rocks.
Low levels of radioactive iodine-131 believed to be from the Fukushima plant have also been detected by nuclear power stations in North Carolina and Florida.
Monitors at Progress Energy's nuclear plants in South Carolina and Florida picked up low levels of radioactive iodine-131. So did Duke Energy's monitors at its two nuclear facilities in South Carolina and in North Carolina.
(Reporting by Timothy Gardner; Additional reporting by Harriet McLeod; Editing by Deborah Charles)