On December 1970, a 10 kiloton nuclear device code-named “Baneberry,” was detonated underground at a depth of 912 feet at the Nevada Test Site. Three minutes later an explosion vented along a 315-foot fissure and spewed a large black radioactive cloud into the air. Wind currents carried the cloud downrange and over a worker’s campsite known as Area 12, which housed 900 people. Approximately 300 men were contaminated by the cloud, among them Harley Roberts and William Nunamaker. They later developed leukemia and filed suit against the federal government in February 1972, claiming that their leukemia was caused by excessive exposure to the radioactive cloud, which in turn resulted from government negligence.

Both Nunamaker and Roberts died in 1974, and their suits were pursued by their widows. The consolidated suits, William Nunamaker vs. the United States and Harley Roberts vs. the United States, came to trial January 1979, in Federal District Court, Las Vegas, U.S. District Judge Roger Foley presiding. Foley issued his ruling in two parts; in part one, issued June 1982, Foley found the government negligent in its evacuation and decontamination procedures. But in the second part, he found that the radiation exposure from the cloud was not sufficient to have caused leukemia. Therefore the plaintiffs proved negligence but not causation. The claimants filed motions in May 1984, requesting either a new trial or reopening the old one, in order to introduce additional evidence. Foley denied the motion and the case was closed.