Health

Future cancers from Fukushima plant may be hidden

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Even if the Fukushima nuclear plant disaster, the worst accident in 25 years, leads to many people developing cancer, we may never find out.

Looking back on those early days of radiation horror, that may sound implausible.

But the ordinary rate of cancer is so high, and our understanding of the effects of radiation exposure so limited, that any increase in cases from the Fukushima nuclear plant disaster may be undetectable.

Several experts inside and outside Japan told The Associated Press that cancers caused by the radiation may be too few to show up in large population studies, like the long-term survey just getting under way in Fukushima.

That could mean thousands of cancers under the radar in a study of millions of people, or it could be virtually none. Some of the dozen experts the AP interviewed said they believe radiation doses most Japanese people have gotten fall in a "low-dose" range, where the effect on cancer remains unclear.

The cancer risk may be absent, or just too small to detect, said Dr. Fred Mettler, a radiologist who led an international study of health effects from the 1986 Chernobyl disaster.

That's partly because cancer is one of the top killers of people in industrialized nations. Odds are high that if you live long enough, you will die of cancer. The average lifetime cancer risk is about 40 percent.

In any case, the 2 million residents of Fukushima Prefecture, targeted in the new, 30-year survey, probably got too little radiation to have a noticeable effect on cancer rates, said Seiji Yasumura of the state-run Fukushima Medical University.

Yasumura is helping run the project.

"I think he's right," as long as authorities limit children's future exposure to the radiation, said Richard Wakeford, a visiting epidemiology professor at the Dalton Nuclear Institute at the University of Manchester in England. Wakeford, who's also editor of the Journal of Radiological Protection, said he's assuming that the encouraging data he's seen on the risk for thyroid cancer is correct.

The idea that Fukushima-related cancers may go undetected gives no comfort to Edwin Lyman, a physicist and senior scientist with the Union of Concerned Scientists, a group that advocates for nuclear safety. He said that even if cancers don't turn up in population studies, that "doesn't mean the cancers aren't there, and it doesn't mean it doesn't matter."

 "I think that a prediction of thousands of cancer deaths as a result of the radiation from Fukushima is not out of line," Lyman said. But he stressed that authorities can do a lot to limit the toll by reducing future exposure to the radiation. That could mean expensive decontamination projects, large areas of condemned land and people never returning home, he said. "There's some difficult choices ahead."

Japan's Cabinet this month endorsed a plan to cut contamination levels in half within the next two years.

The plant was damaged March 11 by a tsunami triggered by a magnitude-9 earthquake. Japanese authorities estimate it leaked about one-sixth as much radiation as the Chernobyl accident. It spewed radioactive materials like iodine-131, cesium-137 and 29 others contaminating the water, soil, forests and crops for miles around.

So far, no radiation-linked death or sickness has been reported in either citizens or workers who are shutting down the plant.

But while the Fukushima disaster has faded from world headlines, many Japanese remain concerned about their long-term health. And many don't trust reassurances from government scientists like Yasumura, of the Fukushima survey.

Many consumers worry about the safety of food from Fukushima and surrounding prefectures, although produce and fish found to be above government-set limits for contamination have been barred from the market.

Fukushima has distributed radiation monitors to 280,000 children at its elementary and junior high schools. Many children are allowed to play outside only two or three hours a day. Schools have removed topsoil on the playgrounds to reduce the dose, and the Education Ministry provided radiation handbooks for teachers.

Thousands of children have been moved out of Fukushima since the March disasters, mainly due to radiation fears.

Many parents and concerned citizens in and around Fukushima, some even as far as Tokyo, carry Geiger counters for daily measurement of radiation levels in their neighborhoods, especially near schools and kindergartens. The devices are probably one of the most popular electronics gadgets across Japan these days. People can rent them at DVD shops or drug stores in Fukushima.