Consequences of the nuclear tests of the United States

The United States conducted 1,032 nuclear tests between 1945 and 1992: at the Nevada Test Site, at sites in the Pacific Ocean, in Amchitka Island of the Alaska Peninsula, Colorado, Mississippi, and New Mexico.

The Nevada Test Site

Between 1951 and 1958, around 100 nuclear weapons tests were conducted in the atmosphere at the Nevada Test Site (NTS). Located about 100 km northwest of Las Vegas, the NTS was larger than many small countries, offering some 3,500 square km of undisturbed land.

The average yield for the atmospheric tests was 8.6 kilotons (kt). The fallout from the tests contained radionuclides and gases which were transported thousands of miles away from the NTS by winds. As a result, people living in the United States during these years were exposed to varying levels of radiation.

Sedan also created the largest man-made crater in the United States, displacing over 12 million tons of earth.

Little information was released during this time about human exposure to the fallout. For example, in the November/December 1997 issue of the Bulletin of the Atomic Scientists, Pat Ortmeyer and Arjun Makhijani stated that the U.S. government failed to share the results of research conducted in 1950 indicating that milk would be contaminated by fallout.

Radioactive fallout from Sedan explosion

A number of underground tests were also carried out from September 1957, with all testing going underground after 1962. “Storax Sedan” was part of the Operation Plowshare program to investigate the use of nuclear weapons for peaceful purposes such as mining. It caused more radioactive fallout contamination than any other nuclear explosion conducted in the United States. Detonated on 6 July 1962, Sedan released roughly 880,000 curies of Iodine 131 into the atmosphere. Detected radioactivity was especially high in parts of Iowa, Nebraska, South Dakota and Illinois, exposing millions of people to radioactive fallout. It also created the largest man-made crater in the United States, displacing over 12 million tons of earth.

A significant amount of radiation was also vented by around 30 other underground tests. The radionuclides contained in this fallout were carried thousands of miles from the NTS.

Increase in number of leukaemia cases

The lethal potential of the nuclear tests was not immediately apparent to downwind residents. An increasing number of leukaemia cases started occurring in people living downwind of the NTS, according to the 1982 publication Killing Our Own: The Disaster of America’s Experience with Atomic Radiation by Harvey Wasserman and Norman Solomon.

In an article entitled Cancer Among Military Personnel Exposed to Nuclear Weapons, the American Cancer Society explains: “In the late 1970s, a higher than usual number of cases of leukemia (4 expected, 10 found) was seen among the 3,000 troops present at the "Smokey" nuclear test in Nevada in August 1957. The question arose as to whether these cases were caused by radiation from the nuclear tests….A recent study compared about 1,000 veterans who received the highest doses of radiation to other veterans who were minimally exposed. The risk of dying from some blood-related cancers (certain leukemias and lymphomas) was more than 3 times higher in those exposed to radiation, and the risk of dying overall was also slightly higher (about 22%). However, the risk was not increased for other types of cancers known to be caused by radiation, and the overall risk of dying from any form of cancer was not higher.”

Philip Fradkin also describes in Fallout: An American Nuclear Tragedy, how two nuclear tests (Dirty Harry and Shot Nancy in 1953) resulted in the deaths of 1,420 lambing ewes and 2,970 lambs in Nevada, Utah, and Arizona from severe radiation injuries.

On 10 May 1984, U.S. District Court Judge Bruce S. Jenkins ruled that radioactive fallout from above-ground nuclear tests in the 1950s had caused ten people to die of cancer and that the government was guilty of negligence in the way it had conducted the tests. It was the first time that the explosions at the NTS had been legally held to have caused cancers. The judge ruled that the government had also been negligent in failing to warn residents of Nevada, southern Utah and northern Arizona, who lived in the path of the tests' wind-borne fallout plumes, about the danger of radioactive contamination. The government was also said to have failed to measure distant radiation from the atomic blasts adequately and to inform the residents of ways to minimize the contamination.

Hazards of exposure to Iodine-131 [I-131]

An important study which estimated thyroid doses of I-131 received by Americans from Nevada atmospheric nuclear bomb tests was released by the National Cancer Institute (NCI) in October 1997. The study found that any person living in the United States since 1951 had been exposed to some radioactive fallout, and all of a person’s organs and tissues had received some exposure. It concluded that the most serious health consequence was internal exposure to the radioactive form of iodine, called radioiodine or I-131 (see Chart 1), which is present in fallout from nuclear weapons. When ingested or inhaled by breast-feeding mothers, I-131 can also be transferred to nursing infants via the mother's breast milk.

When assessing milk contamination, the NCI found that fallout from the tests could eventually cause between 11,000 and 212,000 thyroid cancers. Those who had been children during the testing period were particularly vulnerable, with girls being at twice the risk of boys. Children who had drunk a lot of fresh milk received the highest doses.

A 2002 analysis of government studies by the American policy organization, Institute for Energy and Environmental Research, estimated that over 15,000 thyroid cases caused by nuclear weapon testing would be fatal.

The website of the International Physicians for the Prevention of Nuclear War cites a preliminary study of people downwind from the Hanford Nuclear Reservation, the largest nuclear weapons production facility in the United States. The study “indicates that over 20,000 children may have been exposed to the I-131, partially through contaminated milk and food. Of 270,000 people living in the area, 13,500 may have received more than 33 rads over a 3-year period well in excess of the 5-rad per year limit. Babies may have received a 2,900-rad exposure to their thyroids.”

Legislation passed to compensate victims

The Radiation Exposure Compensation

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