Air samples taken during and after the Hanford nuclear reservation fire last month showed plutonium concentrations in public areas outside the reservation 1,000 times higher than normal levels, but below all Washington state and federal safety standards.
Five of 41 routine monitoring samples contained above normal concentrations, however, experts from EPA and the state said there was no reason for alarm.
The five increased readings were measured in the Pasco, Richland and West Richland communities, which are within 10 miles of the reservation.
"They are on the order of a thousand-fold lower than what would drive public protective action," said Jerry Leitch, EPA''s regional radiation program manager. "I don''t think anybody needs to change anything they do, day to day, based on these results."
People on average absorb about 350 millirem of radiation a year from a variety of sources, said EPA.
Hundreds of air, soil and vegetation samples were taken during and after last month''s 191,000 -acre wildfire burned nearly half the reservation, the most contaminated nuclear site in the country.
In the coming weeks, federal and state officials will release results from radiation tests on vegetation and a handful of firefighters most likely to have been exposed to radioactive elements.
Plutonium, the material processed at Hanford for use in the bomb dropped on Nagasaki during World War II, exists in the atmosphere already, as fallout from Cold War experiments.
EPA said the plutonium concentrations recently discovered are no higher than those detected nationwide after nuclear testing during the 1960s and 1970s. And those were not considered above safety standards.
by Virginia Sutcliffe