The Szilár petition, drafted by scientist Leó Szilárd, was signed by 155 scientists working on the Manhattan Project in Oak Ridge, Tennessee, and the Metallurgical Lab in Chicago, Illinois. It was circulated in July 1945 and asked President Harry S. Truman to consider an observed demonstration of the power of the atomic bomb first, before using it against people. However, the petition never made it through the chain of command to President Truman. It also was not declassified and made public until 1961.