Forgotten Fallout: What is the legacy of the radioactive rains?

North Dakotans, South Dakotans and Minnesotans probably never thought of themselves as living downwind from the Nevada Test Site—the firing range for nuclear bombs.

But they were.

A Forum study of government reports and other documents found that areas of the tri-state region received significant amounts of low-level radioactive fallout during the 1950s and early 1960s.

Because of the long latency period for many cancers, some argue that the long-term human price of open-air nuclear testing is just becoming evident

Today, years after the dust settled, the controversy lingers:


  • Fargo was cited as an example of a “hot spot,” an area of unusual fallout, in 1959 congressional hearings. Radioactive debris in the soil increased more than ten-fold from June to July 1957 after rains from fallout clouds.

  • A 1966 study estimated that infants fed milk produced in the Fargo area after the July 1957 fallout episode received a significant dosage of radioactive iodine. The Fargo levels for one summer were comparable to those accumulated over four years by infants in a Utah fallout town. Studies have linked radioactive iodine to thyroid cancer.

  • During the late 1950s and early 1960s, milk from Mandan and southcentral North Dakota had the highest concentrations of radioactive strontium—a cause of leukemia and bone cancer—in the country.

  • A formerly classified government report comparing 1957 soil samples found radioactivity in dirt from Belle Fourche, S.D., higher than Nevada and Utah samples. The document described Belle Fourche as an area of known heavy fallout form a single detonation.

  • A 1987 study found a higher-than-expected leukemia death rate in South Dakota, and attributed the abnormal rate to fallout from 32 radioactive clouds known to have crossed the state.

  • A national study, published in 1987, correlated increased leukemia rates with radioactive fallout. The study rated Minnesota the fifth-ranking fallout state, as measured by strontium content in soil, bone and food.

  • Documents indicated foliage from a farm near Alexandria, Minn., emitted radioactivity 75 to 100 times the natural levels—more than a year after fallout fell in the area. The U.S. government denied the farmer’s claim that fallout killed 92 sheep in 1957, calling the levels unharmful.

  • A researcher’s 1987 report said an official suppressed the numbers because they “might be misinterpreted, and thus damaging” to the government’s atomic weapons program.

  • A University of North Dakota scientist would like to study long-term effects of fallout in North Dakota. The researcher’s hope is to resolve long-unanswered questions.

Government officials and some scientists maintain that the enduring fallout risks are not significantly greater than natural radiation from sunlight and the earth.
But others disagree—and note that people often were unwittingly breathing, eating and drinking radioactive fallout particles.

Mishaps at Three Mile Island and especially Chernobyl are reminders that fallout did not stop with the cessation of open-air nuclear tests, and that it does not recognize boundaries.

Fallout was, and is, a worldwide phenomenon.

Radioactive debris from above-ground tests in Nevada and abroad was distributed throughout the world by the jet stream.

Distribution of the radioactive sediment was relatively uniform, but hot spots occurred when fallout clouds coincided with heavy rains.

To protect residents in populated cities around the Nevada Test Site, scientists timed detonations so northeasterly winds carried the fallout clouds away. The idea was for the radioactive plumes to travel several hundred miles over arid, sparsely populated country, shedding most of the hottest fallout near the test site.

But if the clouds persisted on their northeasterly trek, they often crossed the Dakotas and Minnesota—sometimes encountering their first rains.

North Dakota and Minnesota were described as hot spot areas during 1959 hearings by Congress’ Joint Committee on Atomic Energy.


Wheat from Crookston, Minn., had the highest strontium level in the country at the time, while milk from Mandan claimed that distinction.

Walter Selove, a Pennsylvania physicist and chairman of the Radiation Hazards Committee of the Federation of American Scientists, urged Congress to alert residents in hot spot areas.

“People exposed to the higher ‘hot spot’ fallout levels should be given as clear as possible a statement as to just what the extent of the hazard is,” Selove was concerned.

And, as Selove and others pointed out, because the states are part of the nation’s breadbasket, the hot spots were being exported in food products to consumers throughout the country.

State health officials assured North Dakotans there was no cause for worry from the distinction of being the state with the highest radioactive strontium in milk; all levels were in the range presumed safe.

Others were not so certain.

And since that time, many safety levels for radiation have been sharply reduced, as a scientific consensus grew that no one can say with certainty what is a “safe” level of radiation.

The government established monitoring stations across the country—and maintains them today—to collect fallout information, which was published.


But critics and scholars argue that the government tightly controlled sensitive information about the effects of fallout, suppressing much of it to protect the nuclear weapons testing program and fledging atomic energy industry.

The consequence of that secrecy, say the critics, is that a cloud of uncertainty still lingers. And the full seriousness of fallout incidents undisclosed at the time cannot be known.

Gene Christianson of the North Dakota Health Department said state officials depended on the expertise of federal officials, but would liked to have been better informed.

“I guess one is faced with really relying on good government to protect the public from those sorts of things,” he said.

Experts debate whether long-term health problems can be attributed to radiation from decades-old fallout.

Some scientists blame the radiation for increased cancers, notably leukemia. Others contend there are no measurable health effects to the general population.

“I cannot rule out that there can be some individuals who have been harmed by the Nevada fallout,” said David Wheeler, a health physicist for the Department of Energy in Las Vegas. “But you can’t identify how many there would be or who they would be.”


Patrick Springer first joined The Forum in 1985. He covers a wide range of subjects including health care, energy and population trends. Email address:
Phone: 701-367-5294
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