Between 1951 and 1992 928 nuclear tests took place at the Nevada Test Site [NTS]. One hundred of these were above ground. The last atmospheric test detonation at the Nevada Test Site was “Little Feller” of Operation Sunbeam, on 17 July 1962.
The NTS is only 65 miles [105 km] from Las Vegas and the mushroom clouds from the above ground detonations were clearly visible from the city. However, above ground tests were only conducted when the wind was from the west and fallout would not affect LV or California. Cities to the east of the NTS were not so protected. The city of St. George, Utah was the worse affected by fallout from the NTS.
From the mid-1950s through 1980 the city and southern Utah reported marked increases in cancers, such as leukaemia, lymphoma, thyroid cancer, breast cancer, melanoma, bone cancer, brain tumours, and gastrointestinal tract cancers. The 1953 detonation of the 32 kiloton “Dirty Harry” bomb generated a tremendous amount of fallout. Winds carried fallout 135 miles (217 km) to St. George, where residents reported “an oddly metallic sort of taste in the air.” ”
Claudia Peterson has a vivid memory from her 1950s childhood in southern Utah. She remembers watching a glowing orange ball move off the western horizon while she rocked back and forth in her swing set the summer she was four, and walking past piles of dead lambs during lambing season. Some had two heads, and others had no legs. Peterson remembers men in tidy, black suits visiting her classroom at East Elementary School in Cedar City with Geiger counters—and feeling a sense of pride that she lit up the counter when they waved it in front of her face. They told her it was from dental x-rays, but she knew she had never had one. She recalls sixth grade when one of her schoolmates died of leukemia, and eighth grade when bone cancer took first her friend’s leg and then his life.” National Geographic
In a 1997 report it was determined that ninety atmospheric tests at the NTS had deposited high levels of radioactive iodine-131 across a large portion of the contiguous United States, especially in the years 1952, 1953, 1955, and 1957—doses large enough to produce tens of thousands of cases of thyroid cancer. By 2014 28,880 claims for compensation had been approved for a total compensation of $1.9 billion.
Iodine-131 Fallout From the Nevada Test Site ”
Rain, wind, and the food supply spread Iodine 131 from these tests across the United States, with the largest deposits immediately downwind of the test site and the lowest on the West Coast, upwind of the site. Exposure to released iodine occurred mainly during the first two months following a test. After that I 131 disintegrated to harmless levels. Because I 131 accumulates in the thyroid gland, the National Cancer Institute estimates that the fallout may have caused up to 212,000 cases of thyroid cancer in people who were exposed. The average cumulative thyroid dose to approximately 160 million people who lived in the country during testing was about two rads, about five times the radiation dose emitted by a mammogram. A rad is the measurement unit for the amount of radiation the body absorbs. The federal government recommends medical monitoring for people who have been exposed to ten rads or more.
Americans were exposed to varying levels depending on their residence, age, and food consumption. People who lived in Western states to the north and east of the site, such as Colorado, Idaho, Montana, South Dakota, and Utah, had the highest per capita thyroid doses, ranging from 9 to 16 rads. And children between three months to five years old in these high fallout areas probably received three to seven times the average dose for the population in their county because they had smaller thyroids and tended to drink more milk than adults. Milk was a major exposure vehicle because I 131 fell on pasture grasses and then was consumed by cows. But an estimated 20,000 people who drank goats’ milk during testing were at an even greater risk because it concentrates Iodine 131 more than cows’ milk. Thyroid doses to these individuals could be 10 to 20 times greater than to residents of the same county, who were the same age and gender, and drank an equal amount of cows’ milk. Other pathways included inhaling contaminated air or ingesting tainted leafy vegetables, cottage cheese, and eggs.” National Geographic