Japan has distributed potassium iodine tablets to residents who may have been exposed to radiation from the nuclear power plants damaged by the recent earthquake, but in recent years, U.S. authorities have questioned whether the benefits of such pills have been exaggerated or misunderstood.
Potassium iodine, or what’s known as KI, “is not an ‘anti-radiation’ drug,” then-White House official John Marburger wrote in a 2008 memo [PDF]. “Public misunderstanding of KI and its limits may lead to a dangerous sense of false confidence that KI provides inoculation against all forms of radiation.”
Potassium iodide helps protect against thyroid cancer—a major risk following radiation exposure—by reducing the amount of radioactive iodine absorbed by the thyroid gland, according to the U.S. Nuclear Regulatory Commission. It doesn’t protect other organs, and it doesn’t protect against other radioactive materials.
The Bush Administration scrapped a plan [PDF] to distribute these pills more widely to residents near the nation’s more than 100 nuclear reactors, finding that evacuating residents and keeping contaminated food from them could be more effective: “The focus on evacuation should not be diverted or confused by attempts to distribute KI from stockpiled locations,” the memo said.
The decision outraged Rep. Ed Markey, the Massachusetts Democrat who had successfully pushed legislation calling for distribution of the pills to be expanded from a 10-mile radius to a 20-mile radius for residents living in the vicinity of nuclear power plants.
The nuclear commission’s current position is that iodine pills don’t make sense for those beyond a 10-mile radius. Instead, wrote the commission, the “major risk of radioiodine exposure is from ingestion of contaminated foodstuffs, particularly milk products”—and the most effective way to deal with that is to simply avoid milk or other contaminated dairy.
Dr. David J. Brenner, director of the Columbia University’s Center for Radiological Research, also downplayed the pills’ effectiveness to the New York Times:
Dr. Brenner said the iodine pills were protective, but were “a bit of a myth” because their use is based on the belief that the risk is from inhaling radioactive iodine. Actually, he said, 98 percent of people’s exposure comes from milk and other dairy products.
“The way radioactive iodine gets into human beings is an indirect route,” he said. “It falls to the ground, cows eat it and make milk with radioactive iodine, and you get it from drinking the milk. You get very little from inhaling it. The way to prevent it is just to stop people from drinking the milk.”
States and local governments may request tablets from the Nuclear Regulatory Commission to distribute to residents within the 10-mile range of a nuclear power plant, but they’re not required to.
One NRC official told USA Today in 2007 that one of the concerns about the iodine tablets was that distributing them would stir fears among residents about whether U.S. plants were safe:
[NRC senior advisor for preparedness Patricia] Milligan also says the NRC is concerned about undermining the reputation of the nuclear industry.
"It's always a concern that if you expand the distribution (of the pills), you don't have confidence in the plants," she says. "We have studies that show the safety of our plants."
Questions about whether U.S. nuclear facilities are adequately prepared for a major natural disaster continue to be of concern as Japan races to cool its damaged nuclear reactors and avert a full meltdown.
The NRC, meanwhile, has continued to state that U.S. plants are safe.