Green Run

The "Green Run" was a secret U.S. Government release of radioactive fission products on December 2–3, 1949, at the Hanford Site plutonium production facility, located in Eastern Washington. Radioisotopes released at that time were supposed to be detected by U.S. Air Force reconnaissance. Freedom of Information Act (FOIA) requests to the U.S. Government have revealed some of the details of the experiment. Sources cite 5,500 to 12,000 curies (200 to 440 TBq) of iodine-131 released, and an even greater amount of xenon-133. The radiation was distributed over populated areas, and caused the cessation of intentional radioactive releases at Hanford until 1962 when more experiments commenced.