Fallout Study Offers No Answers

It happened so long ago. Plumes of radioactive iodine, unleashed by nuclear weapons tests during the 1950s, made their way into the bodies of countless Americans.

And that’s the way these Americans have remained: uncounted.

Until now. The government is figuring out exactly how many people were exposed. And the release of this report may, eventually, pin the blame for some of the nation’s 1,200 deaths a year from thyroid cancer on the testing.

“It’s quite clear that there are people living throughout this country who were exposed to radioiodine from fallout at levels that may be of public health concern,” said Tim Connor, associate director of the Energy Research Foundation, a nuclear watchdog group. “There could be anywhere from tens to thousands of people walking around with thyroid diseases caused by ingesting milk that was contaminated with this fallout.”

Many scientists--both in and outside the government--would dispute that. They argue that there is not yet enough evidence that exposure to the fallout caused cancer.

But there is no dispute that an accounting was overdue.

“It’s not open, and it’s not in keeping with the commitment that officials have made for years about the degree to which information such as this needs to be shared,” said Sen. Tom Daschle (D-S.D.).

The National Cancer Institute study, 14 years in the making, focuses on the release and spread of radioactive iodine-131 from a series of U.S. nuclear tests at the Nevada Test Site from 1951 to 1958.

The study looks at the level of exposure in each of the nation’s more than 3,000 counties and breaks down the dose exposure by age and sex, among other categories.

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Two smaller investigations that used preliminary information from the study found an increase in thyroid cancers possibly due to the nuclear tests:

* Iodine-131 in fallout may have increased the number of thyroid cases expected to occur in North Dakotans by 5% to 10%, according to a 1994 report by Stephen McDonough, chief of the preventive health section of North Dakota’s Department of Health.

* Girls born in 1952 who consumed fresh milk contaminated from test fallout at Oak Ridge, Tenn.--a center of the atomic-bomb-producing Manhattan Project--had an increased risk of developing thyroid cancer during their lifetimes, according to a draft report for the federally funded Oak Ridge Health Agreement Steering Panel.

It also said there may have been exposures in Oak Ridge that were much lower than those in areas of the northeastern United States.

But Bruce Wachholz, who heads the cancer institute’s Radiation Effects Branch, prefers to point to a study conducted in Utah between 1982 and 1991. That study of 2,473 people found that between zero and six cases of thyroid cancer might be linked to exposure to iodine-131.

The results were inconclusive, but they support his opinion that there is little scientific evidence linking iodine-131 and thyroid cancer, he said.

“You can make the assumption that any increase in radiation exposure is an increase in risk. Whether you make the next step, saying, ‘Well, gee, does that mean they’ll get thyroid cancer?’--that’s another whole leap of logic.”

Regardless, he said, the cancer institute’s study--which he has led since its inception--”says nothing about health consequences.”

Then why do the study?

“We were required by law to do the study,” he said.

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For those who believe the fallout was pernicious, a key concern is the effect of iodine-131 on the thyroids of young children, especially those under 10 who consumed fresh cow’s and goat’s milk.

Once iodine-131 is ingested, it is readily absorbed in a child’s blood and taken up by the thyroid gland. There, radiation emitted from iodine-131 may damage cells, causing benign lumps or cancers.

Dr. Robert Gagel, an endocrinologist at the University of Texas’ M.D. Anderson Cancer Center in Houston, said radiation can throw a wrench into the development of the thyroid gland in young children. “Children are particularly susceptible to this because their cells are dividing at a more rapid rate,” he said.

But Gagel cautioned that it might be difficult to tie fallout from the 1950s to thyroid cancers in the 1990s. “One has to be very cautious about trying to extrapolate from what took place [four decades] ago to what could be going on in an area now,” Gagel said.