Sales of Geiger counters and potassium iodide supplements that can block some radiation have surged nationwide since Friday, fueled by concerns among some Americans that radiation released from Japanese nuclear plants could spread to the United States.But as retailers scramble to restock, experts say the chances that North America will be harmed by radiation from Japanese nuclear reactors damaged in last week's earthquake and tsunami are negligible at best."I think it's exceedingly improbable — I'd say impossible — that this accident would deliver any detectable amount of radiation at ground level in the United States," said Elmer Lewis, a nuclear expert and professor emeritus of mechanical engineering at Northwestern University. "It would be barely detectable and have absolutely no health consequences."The U.S. Nuclear Regulatory Commission said Sunday that the country is "not expected to experience any harmful levels of radioactivity."Despite those statements, potassium iodide supplements — which can protect the thyroid gland if taken before or shortly after a person is exposed to radiation but do not protect other body parts or prevent damage from other radioactive substances — are either sold out or selling quickly at several Chicago-area stores."I've had probably upwards of 100 calls in the last few days concerning this product," said Brennan Cox, an assistant manager at The Vitamin Shoppe in Lincoln Park. He said the store's handful of 2-ounce bottles were gone by Saturday.True Nature Foods in Chicago's Edgewater neighborhood also was sold out of potassium iodide Tuesday. That store and Kramers Health Foods in the Loop, which still had some potassium iodide in stock, have been unable to place new orders, employees at both stores said.Deerfield-based Walgreen Co. reported that its stores on the West Coast have been receiving inquiries about potassium iodide, but the company does not stock the product, spokesman Jim Cohn said.Meanwhile, companies that sell Geiger counters have been overwhelmed with orders."The phone has been ringing off the hook," said Raphael Karunditu, president of California-based Gamma-Scout. "We have hundreds upon hundreds of orders, and our partner in Germany is talking about thousands of orders at his site." ||||| Japan's nuclear crisis is spiking demand in the U.S. and a few other places for a cheap drug that can protect against one type of radiation damage _ even though the risk is only in Japan. 
 
 This Tuesday, March 15, 2011 photo shows bottles of potassium iodide on the shelf of the Texas Star Pharmacy on Tuesday, March 15, 2011 in Plano, Texas. The pharmacy has been receiving an unusually high... (Associated Press) 
 
 This Tuesday, March 15, 2011 photo shows a bottle of potassium iodide at the Texas Star Pharmacy on Tuesday, March 15, 2011 in Plano, Texas. The pharmacy has been receiving an unusually high number of... (Associated Press) 
 
 Pharmacist Donna Barsky measures potassium iodide for a prescription at the Texas Star Pharmacy on Monday, March 15, 2011 in Plano, Texas. The pharmacy has been receiving an unusually high number of... (Associated Press) 
 
 Pharmacist Donna Barsky measures potassium iodide for a prescription at the Texas Star Pharmacy on Tuesday, March 15, 2011 in Plano, Texas. The pharmacy has been receiving an unusually high number of... (Associated Press) 
 
 Health agencies in California and western Canada warned Tuesday that there's no reason for people an ocean away to suddenly stock up on potassium iodide. Some key suppliers say they're back-ordered and are getting panicked calls from potential customers. 
 
 "Tell them, `Stop, don't do it,'" said Kathryn Higley, director of radiation health physics at Oregon State University. 
 
 "There's a lot of mythology about the use of potassium iodide," added Dr. Irwin Redlener, a pediatrician and disaster preparedness specialist at Columbia University. "It's not a radiation antidote in general." 
 
 The pill can help prevent radioactive iodine from causing thyroid cancer, for which children are most at risk in a nuclear disaster. 
 
 Japan's Nuclear Safety Agency has stored potassium iodide to distribute in case of high radiation exposure, and the U.S. Navy is giving it to military crews exposed to radiation as they help with relief efforts in Japan. But government and independent experts say that Americans have little to fear from any radiation released by the damaged Japanese nuclear plant. 
 
 "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," said Nuclear Regulatory Commission Chairman Greg Jazcko. 
 
 Other governments echoed that warning. 
 
 "We do not expect any health risk following the nuclear reactor releases in Japan, nor is the consumption of potassium iodide tablets a necessary precaution," British Columbia's health ministry told the public Tuesday. 
 
 In Russia, where memory of the very different Chernobyl disaster 25 years ago is strong, media reports said pharmacies in Vladivostok, a major port just west of Japan, had run out of the pills. 
 
 "The mass media tells us that the wind is blowing the other way, that radiation poses no threat. But people are a mess," Valentina Chupina, a nanny in Vladivostok, said in a comment posted on the website of the newspaper Delovoi Peterburg. She said people don't believe the government will warn them if something goes wrong so potassium iodide is being bought up in the pharmacies. 
 
 In the U.S., whether people fear fallout from Japan or a nuclear accident here, potassium iodide seems to have become something of a hot commodity. 
 
 "I feel strongly there is a high likelihood we will have radiation coming from Japan," said Tammy Lahutsky as she waited at the Texas Star Pharmacy in Plano, Texas on Tuesday. There's not, but she bought six bottles for herself and a friend, anyway. 
 
 "I can't tell you how many women are calling up in tears," said Alan Morris, president of Anbex Inc., a leading supplier. His order line ringing in the background, Morris said the company had sold out of more than 10,000 14-pill packages and doesn't expect more supply until April. 
 
 Internet seller NukePills.com donated 50,000 potassium iodide tablets to a physician-run disaster-relief team in Japan, pills not suitable for U.S. retail sale because of packaging issues and expiration dates. Regardless, "these pills really needed to go where people were in the most dire need," said company president Troy Jones. Meanwhile, he said he's taken over 6,000 orders since Friday and is selling a liquid version until more pills become available. 
 
 What does this drug do? 
 
 Potassium iodide, a salt also known as KI, has just one use: It shields the thyroid from radioactive iodine. It blocks no other type of radiation, and protects no other body part. 
 
 The drug, either pill or liquid form, is sold over-the-counter and is considered safe, although some people may experience allergic reactions. 
 
 Potassium iodide is most important for children and pregnant women, because a growing thyroid is much more active and more likely to absorb radioactive iodine, said Columbia's Redlener. It should be given within a few hours of radiation exposure _ but isn't considered that useful for people over age 40. 
 
 At the same time, the crisis renews a question that the U.S. government has debated for years: Should people keep small supplies of potassium iodide on hand in case of a local radiation emergency? 
 
 The federal government already stockpiles the drug, and offers enough for states also to keep on hand to treat every resident within 10 miles of a nuclear reactor. About 22 states have requested or received some of those doses, and localities periodically offer free supplies for nearby residents to store themselves. 
 
 But radiation health specialists debate whether a 10-mile radius is big enough _ and whether people should store their own. Some are pushing the Obama administration to reconsider. Obama health officials wouldn't comment Tuesday. 
 
 "My feeling is I would have every household within of a plant have it in their medicine cabinet," said Redlener, adding that the Japan crisis illustrates the difficulty of getting pills from a central warehouse to panicked people during an emergency. 
 
 Even on the East Coast, some health departments reported increased interest from power-plant neighbors Tuesday: A Pennsylvania hotline that normally gets five to 10 calls a week about storing the pills has fielded 85 such inquiries in the past two days.
– An ocean away from the unfolding nuclear crisis in Japan, worried Americans are stocking up on Geiger counters and supplements that can block one effect of radiation exposure. Pharmacies around the country are rapidly running out of potassium iodide, which can protect the thyroid gland from radiation damage, the AP reports. Suppliers say they are receiving calls from panicked customers, but experts say Americans shouldn't worry about being exposed to radiation from Japan, and shouldn't bother buying potassium iodide unless they live near a nuclear plant. "I think it's exceedingly improbable—I'd say impossible—that this accident would deliver any detectable amount of radiation at ground level in the United States," a nuclear expert tells the Los Angeles Times. "It would be barely detectable and have absolutely no health consequences."