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On August 1, the National Cancer Institute (NCI) revealed that as a result of U.S. nuclear tests conducted at the Nevada Test Site (NTS), American children were actually exposed to 15 to 70 times as much radiation as had been previously reported to Congress. As a result, many thousands of today's adults are at risk of developing thyroid cancer.
The information comes from fragments of a congressionally mandated study, 14 years in the making. The NCI report details estimated radiation doses to the thyroid gland due to releases of radioactive iodine 131. Most of the releases occurred from 1951 to 1958.
Although areas near the Nevada test site were most often contaminated, the newly released data show that virtually the entire continental U.S. was affected, and "hot spots" also occurred in unpredictable places far from the site. These hot spots occurred because rainstorms sometimes caused locally heavy deposits of fallout. As a result, some children in large portions of the Midwest, parts of New England, and areas east and northeast of the test site (Idaho, Montana, and the Dakotas), received doses of iodine 131 as high as 112 rad.
These dose estimates refer not to whole-body exposure, but to the concentration of iodine-131 in the thyroid gland, which occurred primarily through the "milk pathway." As cows and goats grazed in fallout-contaminated pastures, iodine 131 contaminated their milk. Children received higher thyroid doses because they drank much more milk than adults, and because their thyroids were smaller and still growing. In making its county-by-county estimates, NCI used both milk production and consumption patterns as well as weather data.
What the Government Knew
Given the location of the U.S. test site, none of the NCI's findings should come as a surprise to the nuclear weapons establishment, which knew from the beginning that a Western test site would spread contamination across most of the country. In 1948, for instance, the committee assigned to choose a location was told by U.S. Air Force Meteorologist Col. B. G. Holzman that an East Coast site would be advisable "because the United States is predominantly under the influence of westerly winds." (1)
Instead, the committee chose a Western site because the weapons labs were nearby, which it felt would be helpful in "accelerating the pace of the weapons development program."(2)
Estimates of thyroid doses, first reported in testimony to Congress in 1959 and still cited in 1997, range from 0.2 to 0.4 rad.(3) (According to the NCI, 0.4 rad is roughly the radiation dose delivered by one mammogram.) But American children on average actually received an estimated cumulative dose to the thyroid of 6 to 14 rad, and in the 24 most heavily contaminated counties, between 27 and 112 rad.
The exposure of millions of children is especially troubling because much of it could have been avoided. The Atomic Energy Commission (AEC) learned of the risks of fallout and the prevalence of hot spots with the first atomic test, and the AEC was aware of the danger of consuming contaminated milk during most of the years of testing at NTS.
Authorities had an early tangible warning that fallout from nuclear tests would travel far from the site of a detonation and that care would be needed to contain it. Fallout was discovered 200 miles from the test site where "Trinity," the first nuclear bomb, was detonated in New Mexico in July 1945. As a result, Stafford Warren, the Manhattan Project's chief of radiological safety, recommended to Gen. Leslie Groves, head of the project, that future tests should be conducted at least 150 miles away from civilian populations.(4)
The Trinity test also resulted in at least one hot spot in Indiana, over 1,000 miles away. One month after the test, the customers of the Eastman Kodak Company complained of buying fogged X-ray film. After an investigation, a physicist at Eastman Kodak determined that packing material that had been made from corn husks at a plant in Indiana had become radioactively contaminated. He deduced that the origin of the contamination was from an atomic explosion. The physicist's knowledge of the secret project was not altogether surprising: the Kodak Company ran the Tennessee Eastman uranium processing plant at the Oak Ridge National Laboratory.(5)
Kodak also reported problems from fallout after the first test in Nevada in January 1951, but this time they occurred as far away as company headquarters in Rochester, New York. After a snowstorm, Geiger counters at the Kodak plant showed readings 25 times above normal. When Kodak complained and threatened to sue, the Atomic Energy Commission agreed to give the company "advance information on future tests," including "expected distribution of radioactive material in order to anticipate local contamination."(6)
In fact, the entire photographic film industry was warned about fallout. Throughout the atmospheric testing program, AEC officials gave the photographic industry maps and forecasts of potential contamination, as well as expected fallout distributions which enabled them to purchase uncontaminated materials and take other protective measures. The National Association of Photographic Manufacturers was also given some data on the nature of the test shots, "for their own information."(7)
But the AEC did not see fit to provide milk producers or consumers with similar information, even when the significance of the milk pathway became clear.
One of the better known hot spots occurred in Albany, New York after the "Simon" test in April, 1953. After a heavy rainstorm, students in a college radiochemistry class noticed that their Geiger counters were showing readings as high as 1,000 times above normal.(8) Measurements taken of roofs, puddles, buildings, and foliage around town showed similar elevated readings. In a 1954 report, the AEC described this incident as "an interesting example of a small area of very intense fallout."(9)
But the AEC report evaluating the Albany incident also indicated that fallout as far as 600 miles from the test site, in areas such as western Kansas, could deposit 1,000 to 100,000 times the radioactivity recorded in Albany.(10) The report also recommended that, since hot spots were more likely to occur during months with the greatest precipitation, "total fallout in the United States could be reduced somewhat by scheduling test series in the late fall," when storms were least likely to occur.(11)
This recommendation was largely ignored.
Deceit and denial
Although public concern about fallout grew in the early 1950s, the AEC consistently denied that the public was in danger. But the AEC's collection of milk samples was haphazard at best. For example, in 1953, the Public Health Service was asked to obtain milk samples in St. George, Utah, near the test site. But the service took a sample from a carton of milk purchased in a store, not from a local farm or dairy -- at a time when the majority of residents of southwest Utah obtained milk from their own cows and many others purchased milk from neighboring farms.(12)
According to Morgan S. Seal, a fallout monitor with the Public Health Service, the testing procedure was not very useful either. "In the case of milk, we even treated it with perchloric acid to get rid of all the organic residue....we knew for a fact then that those oxidating techniques completely eliminated any iodine in the material that you were treating."(13)
Studies on animals exposed to iodine-131 had been going on since the 1940s, although they primarily involved direct measurement of the thyroid to detect iodine uptake, rather than whether the radioactive iodine would contaminate the animal's milk.
In 1953, however, researchers at the Hanford Nuclear Reservation studied milk samples from sheep which had been fed iodine-131 pellets and concluded that similar iodine levels in bovine milk "suggest that I-131 would be found in such dairy products as skim milk, cottage cheese, and whey."(14)
In 1954 the Journal of Dairy Research was more direct in discussing the risk to humans of iodine in milk, indicating that "cows grazing in the neighborhood [near a nuclear power plant accident] may ingest sufficient of the isotope to constitute a danger to the consumers of their milk."(15) Also in 1954, AEC- funded research determined that the elevated levels of iodine found in animal thyroids in Tennessee were linked to fallout from nuclear tests.(16)
Additional evidence of the danger of the milk pathway was presented by delegates to the U.N. Conference on Peaceful Uses of Atomic Energy in 1955. One research paper argued that radioactive iodine deposited in grazing areas became so highly concentrated in milk that the then-permissible levels of iodine 131 in air was ten thousand times too high. "This limit should be reduced by four orders of magnitude to assure radiation safety for grazing animals. Approximately the same reduction is required for the safety of humans eating large quantities of fresh garden produce and drinking milk from cows grazing on iodine 131-contaminated pasture."(17) A Oxford University delegation to the conference stressed that "human beings whose diet consists largely of milk, notably infants . . .because of their youth may be considered super-susceptible to the effects of radiation."(18)
Although the Atomic Energy Commission ignored those recommendations, elsewhere attitudes were changing. In 1957, when a fire at Britain's Windscale reprocessing plant caused the release of between 16,200 and 27,000 curies of radioiodine, officials ordered all milk produced within a 200-square-mile area around the plant to be dumped as a precautionary measure.(19) By comparison, cumulative releases of iodine-131 from atmospheric tests during the 1950s were around 150 million curies, but at no time did the government order that milk be dumped.
In 1959, in response to public concerns about fallout, President Eisenhower created the Federal Radiation Council (FRC) and charged it with setting federal radiation standards. When it was discovered that iodine levels in milk in Utah were exceeding FRC standards, and that fallout standards were being exceeded in hot spots around the country, state officials in Utah and Minnesota decided to divert contaminated milk from the market. But in 1962, the radiation council (whose members included the chairman of the AEC and the Secretary of Defense) made the remarkable determination that the radiation guidelines should not be applied to fallout without further detailed studies because "any possible health risk which may be associated with exposures even many times above the guide levels would not result in a detectable increase in the incidence of disease." The council also concluded that preventive measures, presumably such as diverting milk, may actually "have a net adverse rather than favorable effect on the public well-being." (20) In testimony before Congress in 1969, council chairman Paul C. Tompkins defended the failure to divert milk from the market by claiming that doing so would have caused malnutrition.(21)
In 1962 the AEC's Fallout Studies Branch produced a report indicating that after the "Harry" test in 1953, children living in St. George, Utah might have received doses to the thyroid of radioiodine as high as 120 to 440 rad. The AEC tried to suppress the report, but it was eventually released. However, a committee review appended to the report warned that its "specific conclusions must be regarded with considerable reservation." (22)
The evidence of high thyroid doses from contaminated milk continued to grow. In 1966, another AEC study showed that children both directly downwind and far away from the test site had received high thyroid doses of iodine 131 from drinking contaminated milk. The highest thyroid doses were to children directly downwind: infants in St. George, Utah were estimated to have received 120 rad. But across the country, the researchers found significant doses to children from iodine fallout: 46 rad in Salt Lake City, Utah; 56 rad in Roswell, New Mexico; 51 rad in Grand Junction, Colorado; 19 rad in Amarillo, Texas; and 15 rad in Albany, New York.(23)
Fallout from fallout
The National Cancer Institute study, only small portions of which were released in August, did not directly assess the risk of cancer as it relates to fallout. But researchers did predict that some 10,000 to 75,000 excess thyroid cancers can be expected from the reported doses, and that only 30% of those cancers have been diagnosed to date.(24) In 1977 the NCI reported that the incidence of thyroid cancer was on the rise: in a 1969-71 survey there were 3.9 cases of thyroid cancer per 100,000 people, up from 2.4 cases per 100,000 in 1947 -- an increase of 62%. For Caucasians between the ages of 20 and 35, the rate doubled.(25)
However, concluding that cases of thyroid cancer are a result of exposure to iodine-131 is not straightforward; during the years of atmospheric testing, it was also common for physicians to treat an assortment of disorders with X-rays and other radiation sources. For example, from the 1940s to the 1960s, nasal applicators containing sealed radium-226 sources were used to treat nasal and inner ear problems and to reduce swelling of lymphoid tissue.
The National Cancer Institute estimates that around 160 million people - virtually everyone living in the U.S. at that time- received some iodine dose from fallout. But those most at risk, according to a peer-reviewed 1995 study, are people who were exposed while under 15 years of age who received a radiation dose of 10 rad or more. The risk is greatest for those exposed before the age of five.(26)
More specific numbers have not been released, but simple demographics coupled with the published numbers indicate that millions of people who were then under 15 may have been exposed to 10 rad or more. (About five to 10 percent of thyroid cancers are fatal; survivors require lifelong treatment with a synthetic thyroid hormone essential for metabolism and other physiological functions.)
What should be done now?
The National Cancer Institute, which has been working on its study for nearly 14 years, argues that more research is needed. But the need to address uncertainties should not be an excuse for further delay -- the government has a responsibility to the 160 million people who were unknowingly exposed. The complete report and the follow-up studies conducted by the National Academy of Sciences' Institute of Medicine should be released promptly so that those at risk can be notified and given appropriate medical screening.
In its study of populations exposed to iodine-131 releases at Hanford, the Agency for Toxic Substances and Disease Registry recommended screening of all those who received doses of 10 rad or more. Average doses to children in the 24 most affected counties in the NCI study were far greater (27 to 112 rad).(27)
The thyroid survey in the Marshall Islands also offers a precedent: although contamination levels varied widely and no dose reconstruction was carried out, every Marshallese born before 1965 was eventually offered a free clinical examination. (28)
These precedents, at Hanford and in the Marshall Islands, offer a foundation upon which a public policy response to thyroid doses from iodine fallout could be based.
The NCI claims it did not release dose data four years ago when preliminary results were known because the report was not yet complete. However, public health officials should have been informed, given the high dose estimates for many counties across the country. If estimated doses were revised downward in the final version, then no harm would have been done. Since thyroid cancer is highly treatable, screening could have been instituted earlier, possibly saving lives.
The failure to provide adequate warning of the dangers of fallout should not be compounded by a failure to release full information to the millions affected by iodine-131 fallout from atmospheric nuclear testing.
Pat Ortmeyer is Outreach Coordinator for the Institute for Energy and Environmental Research (IEER), and Managing Editor of IEER's newsletter, Science for Democratic Action. Arjun Makhijani is president of IEER.
For more information on the consequences of nuclear testing, see Radioactive Heaven and Earth," IEER's 1991 report published in conjunction with the International Physicians for the Prevention of Nuclear War.
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Updated April 15, 2009