A trace amount of radioactive iodine, well below levels of public health concerns, has been detected in milk from the state of Washington as the U.S. monitors radiation levels amid the nuclear crisis in Japan, U.S. regulators said.
"These types of findings are to be expected in the coming days and are far below levels of public health concern, including for infants and children," the Food and Drug Administration and the Environmental Protection Agency said in a joint statement.
Testing found 0.8 pCi/L of iodine-131, a radioactive form of iodine, in the milk sample.
Although there are naturally occurring levels of radiation in milk, such an isotope is not normally found in milk, but the agencies stressed it was 5,000 times lower than the FDA's standard, known as the "defined intervention level."
"These findings are a minuscule amount compared to what people experience every day," FDA scientist Patricia Hansen said in a statement.
The EPA said it has increased radiation monitoring in U.S. milk, precipitation and drinking water in response to radiation leaks at Japan's Fukushima Daiichi nuclear plant, which was damaged by the huge tsunami that was followed by the massive 9.0 quake on March 11.
The agencies said Iodine-131 has a very short half-life of approximately eight days, and the level detected in milk and milk products was therefore expected to drop relatively quickly.
Contaminated milk is a worry after a nuclear accident because toxic levels of radioactive iodine can get into rainwater and feed that is ingested by cows and taken up in their milk. Contaminated milk was one of the biggest causes of thyroid cancers after the nuclear accident in Chernobyl because people near the plant kept drinking milk from local cows.
Iodine-131 is a threat to human health because it goes immediately to the thyroid gland, where it can cause cancer. Experts say thyroid cancer is generally considered non-fatal because treatments are so effective.