Shot Simon in April of 1953 was the largest open-air tower detonation to date at the Nevada Test Site (NTS)–although less by design as its yield exceeded expectations by 20 percent. It was a brusque 43-kilotons or roughly three times the explosive yield of the device that destroyed Hiroshima, Japan.
As the mushroom cloud raced to 44,000 feet lower-level debris moved eastward and radiological monitors were hastily dispatched to scattered locales. A hotspot was detected near Glendale, Nevada and roadblocks were set-up to scan vehicles. While rad-safe teams were struggling to keep up with close-in debris fallout continued to move across the country in divergent directions at higher altitudes.
The figure below illustrates shot Simon’s turbulent march across the continent-which resembles the twisted, gnarled tines of a damaged fork: at 10,000 feet debris arched northeast towards Salt Lake City and then straight through the Midwest; at 18,000 feet it wandered over northern Arizona and New Mexico before making a sharp swing northward and passing over Pennsylvania; at 30,000 feet fallout dipped south passing over Louisiana and Florida; debris at 40,000 feet adopted a southernly route before abruptly swinging northeast as it passed over Mississippi and reaching speeds over 100 knots (115 miles per hour).
This upper-level stream traversed the country before lower-level segments and in a more concentrated mass. And as it barreled over upstate New York it ran into a thunderstorm bringing hail, high-winds, flooding-and radioactivity.
On the morning of April 27, Dr. Herbert M. Clark a professor in the chemistry department at Rensselaer Polytechnic Institute (RPI) in Troy, New York accompanied his students to a lab filled with Geiger counters clicking at an abnormal pace–the one closest to an outside wall chattering the fastest. They soon realized outside on the pavement, in puddles, and underneath rain gutters, gamma radiation was far beyond natural background levels.
A detonation thirty-six hours earlier at the NTS, Clark surmised, had to be the source. He phoned the Atomic Energy Commission’s (AEC) Health and Safety Laboratory in New York City but was met with disbelief. Nonetheless, his students detected radioactivity on asphalt roof shingles, vegetation, in household tap water, and local reservoirs far in excess of natural background levels.
Radioactivity was detected not just in Troy but Albany and much of upstate New York, southern Vermont, and parts of Massachusetts. Samples of tap water in Albany illustrated radiation activity 2,630 higher than normal. The intensity of gamma radiation was surprisingly high but not deemed by the AEC and the New York State Department of Health to be hazardous, and no actions were taken to inform the public or engage in clean-up efforts.
AEC officials were slow to react to the Troy-Albany rainout, discounted the necessity of cleanup efforts, and were reluctant to admit the potential dose imposed upon area residents. An aerial radiological survey was conducted five days after Clark’s first phone call. As fallout moved eastward over Nevada in the wake of shot Simon roadblocks were setup and vehicles registering 7 millirads (.007 rads) or higher were subjected to mandatory decontamination, and yet much higher readings were detected at Troy-Albany and no remediation efforts were attempted.
Clark’s research illustrated how difficult it would likely be. He and his students discovered radioactive rain is absorbed by porous surfaces and requires repeated scrubbing to achieve successively lower readings.
The AEC conducted follow-up studies, but they were classified. Clark also continued to study the issue under contract with the AEC. He published in Science in 1954 depicting the effort to assess the extent of radioactivity in the wake of Simon. A co-authored article in an obscure academic outlet, Journal of the American Water Works Association, was particularly telling as it documented radioactivity in reservoirs serving Troy residents continued to spike upwards due to rainout of subsequent shots in the Upshot-Knothole series, beyond simply Simon.
AEC officials insisted publicly that the likely dose to residents was 100 millirads (0.1 rads), but during a classified meeting of the AEC commissioners on May 13, 1953–the figure was 2,000 millirads (2 rads). In turn, AEC officials publicly downplayed the intensity of gamma radiation while privately expressing consternation at surprisingly high levels of ionizing radiation so far from the detonation point.
In 1982 a study by the Defense Nuclear Agency estimated the maximum dose of the Troy-Albany rainout to be 2 rem (see Wald 1982). The average resident would normally receive 14 rems of radiation in a lifetime. In a hypothetical scenario in which all 500,000 residents of the Albany area were exposed to 2 rems it would produce an expected 100 additional fatal cases of cancer. Richard L. Miller observes the counties hardest hit include Albany (NY), Columbia (NY), Fulton (NY), Rensselaer (NY), Saratoga (NY), Schenectady (NY), Warren (NY), Washington (NY), Addison (VT), and Bennington (VT)
In June of 1954 Robert J. List of the U.S. Weather Bureau authored a report examining radioactive debris traversing the country during the Upshot-Knothole series of 1953-which consisted of eleven detonations, including Simon. In a classified report, List turned to a troubling question: what if rainout occurred not 2,200 miles from Nevada, as with Simon, but much closer? What if it occurred, say, in Kansas?
He noted this would present a very significant public health hazard.
List raised the question of whether there were there instances of rainout prior to the Troy-Albany episode that went undetected? Laying the meteorological and fallout data atop each other, several such situations were found: New York and New England on November 1, 1951, November 3, 1951, and April 7, 1953; Nebraska on May 26, 1952; and Wyoming on May 8, 1952. The latter case appears to be the one most likely to have produced intense local fallout.
Given the data were not collected at ground-level, it is impossible to assess the degree to which these additional instances of rainout of radioactive debris may have impacted public health. And it is likely this list is a partial one, at that.
For more information:
Herbert M. Clark, “The Occurrence of an Unusually High-Level Radioactive Rainout in the Area of Try, N.Y.,” Science 119, no. 3097 (1954): 619-622; Bill Heller, A Good Day Has No Rain (Albany, NY: Whitston Publishing, 2003).
Heller, A Good Day; Ernest J. Sternglass, Secret Fallout: Low-Level Radiation from Hiroshima to Three-Mile Island (NY: McGraw-Hill, 1981).
AEC, “AEC Meeting Minutes No. 862,” 13 May 1953.
E.J. Kilcawley, H.M. Clark, H.L. Ehrlich, W.J. Kelleher, H.E. Schultz, and N.L. Krascella, “Measurement of Radioactive Fallout in Reservoirs,” Journal of the American Water Works Association 46, no. 11 (1954): 1101-1111.
Matthew W. Wald, “Radiation from 1953 Nuclear Test Fell on Albany,” New York Times, May 2, 1982, Section 1, 48.
Richard L. Miller, in The U.S. Atlas of Nuclear Fallout Volume 1: Total Fallout, 1951-1962, (The Woodlands, TX: Legis Books, 2000),
Robert J. List, “The Transport of Atomic Debris from Operation Upshot-Knothole,” U.S. Weather Bureau, 25 June 1954.