Concerns that radiation from Japan's paralyzed nuclear reactors will reach the West Coast have driven scores of people to seek out a health supplement that counteracts exposure to high levels of radioactive iodine.

Health officials in Oregon, California and Washington say taking potassium iodide isn't needed or recommended. Even so, a number of Douglas County residents are among those seeking the type of salt.

Potassium iodide blocks the absorption of radioactive iodine, which causes thyroid cancer. Children and fetuses face the greatest danger because they absorb radioactive iodine more readily than older people.

A downtown Roseburg vitamin store carries supplies of potassium iodide, while a second vitamin store, which sold out its stock earlier this week, expects a new shipment today.

Several pharmacies throughout central Douglas County either carried small amounts of potassium iodide and sold out or didn't carry it to begin with. Bi-Mart on Garden Valley Boulevard in Roseburg has a prescription version.

“We've tried calling our suppliers, but they don't have any of the over-the-counter version available,” said Christine Nelson, a Bi-Mart pharmacy technician.

Renee Knutson, owner of The Vitamin Market on Garden Valley Boulevard, said she wished she hadn't run out of potassium iodide earlier in the week. She usually sells one or two bottles a month, but demand spiked following the earthquake in Japan and the resulting damage to a series of nuclear reactors.

“I could have sold 15 of them (Wednesday),” Knutson said.

She expected to get in a shipment of 18 bottles of the liquid form today.

People exposed to high levels of radioactive iodine may need to take potassium iodide to lessen the long-term risk of thyroid disease, according to the Public Health Division of the Oregon Health Authority.

The United Nations predicts the radioactive plume could reach the Aleutian Islands today and Southern California late Friday, based on Pacific wind patterns.

On Sunday, the U.S. Nuclear Regulatory Commission said it did not believe radiation “at harmful levels” would reach the United States from Japan, given the thousands of miles between the two countries.

NRC chairman Gregory Jaczko said the plume posed no danger to the United States.

“You just aren't going to have any radiological material that, by the time it traveled those large distances, could present any risk to the American public,” Jaczko said in a White House briefing.

Oregon health officials concur.

“There is no indication at this time that there is any health risk,” the health authority said in a written release.

Oregon public health officials and those from the Environmental Protection Agency will continue to monitor radiation levels, as they've done for the past 25 years. If the situation in Japan worsens and there is a potential risk to Oregonians, public health officials said they will inform the public.

Mystic Earth on Southeast Jackson Street in downtown Roseburg had a good supply of potassium iodide Wednesday, co-owner Ron Sutten said. He said he sold 15 bottles of the liquid form, a mixture of potassium iodide and iodine, on Tuesday.

Sutten said he recommends potassium iodide as a health supplement. It has been touted to ensure healthy thyroid function, for hormone balance, for arthritis prevention and as an expectorant for coughs.

Since last week's earthquake in Japan and the resulting problems with that country's nuclear reactors, which have released small amounts of radiation, interest in potassium iodide has increased, said David Stevens, owner of Gordon's Pharmacy in Canyonville.

“We've been getting calls every day since Monday, about four or five a day,” said Stevens, whose pharmacy does not have any of the supplement.

People taking potassium iodide should read label warnings, he said.

Those with an allergy to iodine should not take the supplement. In addition, those with chronic kidney disease should be cautious taking potassium iodide because it could lead to a dangerous rise in blood potassium levels, according to the Oregon Health Authority.

In addition, pregnant women should use it with caution, as it can affect fetal thyroid growth.

• The Associated Press contributed to this report. You can reach reporter John Sowell at 541-957-4209 or jsowell@nrtoday.com.