Green Run

Green Run. It was a secret Atomic Energy Commission experiment conducted at the Hanford Site in December 1949, involving the intentional release of a large quantity of radioactive fission products from a nuclear reactor's chemical processing plant. The primary purpose was to test monitoring equipment and study the environmental dispersion of iodine-131, a key isotope of concern from atmospheric nuclear testing. The release contaminated a significant area of southeastern Washington and raised later concerns about public health and government transparency.

Background and purpose

The experiment was conceived during the early Cold War, as the United States sought to improve its ability to detect and analyze Soviet nuclear activities. Following the first Soviet atomic bomb test, Joe-1, in August 1949, there was heightened urgency to understand the signatures of plutonium production. Scientists from the Hanford Site, operated by the General Electric Company, and the AEC's Health and Safety Laboratory designed Green Run to simulate the gaseous emissions from a Soviet nuclear reprocessing facility. The goal was to calibrate sampling aircraft and ground-based sensors that would be used downwind of suspected Soviet sites, providing intelligence for agencies like the United States Air Force. This work was directly connected to the nascent Nuclear Arms Race and the monitoring efforts of the Long Range Detection Program.

The experiment

On the night of December 2–3, 1949, operators at Hanford's U Plant, a uranium fuel reprocessing facility, bypassed the standard delay tanks that allowed short-lived radioisotopes to decay. They intentionally vented an estimated 8,000 curies of iodine-131, along with substantial amounts of xenon-133, over a 12-hour period into the atmosphere. Meteorological conditions were monitored, and the radioactive plume was tracked as it traveled eastward across the Columbia River basin. Sampling teams from the AEC and General Electric Company collected data using air filters, vegetation samples, and Geiger counters. The release was conducted without informing the public or local officials in communities like Richland, Pasco, and Spokane, and it occurred despite known health risks associated with iodine-131 absorption by the thyroid gland.

Aftermath and legacy

The experiment was initially deemed a technical success for the monitoring program, but its environmental and public health consequences became a major controversy decades later. In the 1980s, investigations by the United States Department of Energy and hearings led by John Glenn's Senate committee brought Green Run to public light, revealing that radiation levels were hundreds of times higher than reported from normal operations. Studies, including the Hanford Environmental Dose Reconstruction Project, linked the release to potential increased risks of thyroid disease among downwind populations. The secrecy of Green Run fueled legal actions such as the Hanford Downwinders litigation and became a pivotal case in debates over Cold War environmental damage and government accountability, paralleling issues at other sites like the Nevada Test Site and Rocky Flats Plant.

See also

* Project Gabriel * Project Sunshine * Atomic veterans * Windscale fire * Kyshtym disaster

References

Category:Hanford Site Category:Cold War military history of the United States Category:1949 in the United States Category:Nuclear history of the United States Category:Radioactive contamination