CHARLESTON, South Carolina Low levels of radioactive iodine believed to be from Japan's Fukushima nuclear power plant have been detected in the atmosphere in South Carolina, North Carolina and Florida, officials said on Monday.
There is no current threat to public safety, said spokesman Drew Elliot of Progress Energy, the Raleigh, North Carolina, electric utility serving Florida and the Carolinas.
Monitors at Progress Energy's nuclear plants in Hartsville, South Carolina, and Crystal River, Florida, picked up low levels of radioactive iodine-131. So did Duke Energy's monitors at its two nuclear facilities in South Carolina and the plant in Huntersville, North Carolina.
"If there were radiation coming from one our own sites, we would be seeing other types of radiation than iodine-131," Elliot said. "Other nuclear stations throughout the East Coast all started picking this up within the last week. It all points to something coming from overseas.
"The Nuclear Regulatory Commission and the Environmental Protection Agency both say it poses no threat to public safety," he said.
The news follows reports that trace amounts of radioactive iodine have also turned up in rainwater samples in Massachusetts, California, Pennsylvania and Washington state.
On Monday, Pennsylvania Governor Tom Corbett said that tests on public drinking water in six facilities around the state found no elevated levels of radioactivity.
Concentrations of Iodine-131 reported in Pennsylvania's rainwater samples ranged from 40 to 100 picocuries per liter (pCi/L).
Those readings are about 25 times below the level that would be of concern, officials said, adding that rainwater is diluted by water in reservoirs and rivers and is also treated before reaching consumers.
The levels are also below those that could harm livestock or pets, which could consume rainwater directly.
The higher incidence of radioactive iodine is believed to have originated from atmospheric releases from Japan's damaged Fukushima plant, officials said.
But the Pennsylvania samples included those made in the vicinity of nuclear power plants at Three Mile Island and Limerick, where levels were 90 to 100 cPi/L.
Massachusetts officials reported a reading of 79 pCi/L in a sample taken in Boston on March 22.
Monday marks the 32nd anniversary of the start of the Three Mile Island accident, when one of the plant's two reactors suffered a partial meltdown.
(Reporting by Harriet McLeod and Ros Krasny; Editing by Colleen Jenkins and Jerry Norton)