Areas of the United States crossed by two or more clouds from atmospheric nuclear tests in Nevada between 1951 and 1962. Map created by researcher Richard Miller based on AEC records on radiation dispersal from weapons testing. Widely distributed by downwinder activists to demonstrate how the fallout from US tests blanketed most of the country during this era.
from the research files
The spring of 1953 was a busy time in the Southwest. Southern Utah ranchers were herding their sheep back across southern Nevada for lambing. Baby-boomer families were raising children in the small communities scattered across the region. Upwind, the Atomic Energy Commission was busy conducting its Upshot-Knothole atmospheric test series, which included eleven large-scale nuclear weapons. (For purposes of comparison, Hiroshima, Japan was bombed with a 15kt device- approximately 15,000 tons of dynamite. Several of the Upshot-Knothole tests topped 60kt). Enlisted men from every branch of the armed services participated in the tests in order to condition themselves for atomic warfare. Pigs were dressed up in military uniforms and caged in the blast zone, and AEC monitors gathered samples of radiation in wild animals, water, and agricultural products. Citizen concerns were dismissed by government representatives and assurances were repeatedly made that the tests posed no danger to human health in downwind communities.
The Upshot-Knothole series in spring of 1953 released multiple dangerous radioisotopes, many of which were not fully monitored at the time. Perhaps the most comprehensive data exists for Iodine-131, which swiftly entered the food chain via cows milk. The spring 1953 tests account for approximately 25% of the total I-131 exposure to American civilians over 50+ years of weapons testing. That exposure is conservatively estimated to have caused 28,000 cases of thyroid cancer.
Spring of 1953 figures prominently in the stories of downwind residents, many of whom witnessed the mushroom clouds on the horizons from their playgrounds and remember the catastrophic livestock die-offs and miscarriages that followed in subsequent months.
Thanks to Theresa Trebon, who helped comb through hundreds of feet of microfilm to survey newspapers from the downwind region.