United States Department of Energy and the Argonne National Laboratory yielded to public pressure and earmarked $24.7 million and $3.4 million respectively to rehabilitate the site. As part of the cleanup, of radioactive waste was removed and sent to the Hanford Site for disposal. By 2002, the Illinois Department of Public Health had determined that the remaining materials posed no danger to public health. Significance and commemoration The successful test of CP-1 not only proved that a nuclear reactor was feasible, it demonstrated that the k factor was larger than originally thought. This removed the objections to the use of air or water as a coolant rather than expensive helium. It also meant that there was greater latitude in the choice of materials for coolant pipes and control mechanisms. Wigner now pressed ahead with his design for a water-cooled production reactor. There remained concerns about the ability of a graphite-moderated reactor being able to produce plutonium on industrial scale, and for this reason the Manhattan Project continued the development of heavy water production facilities. An air-cooled reactor, the X-10 Graphite Reactor, was built at the Clinton Engineer Works in Oak Ridge as part of a plutonium semiworks, followed by larger water-cooled production reactors at the Hanford Site in Washington state. Enough plutonium was produced for an atomic bomb by July 1945, and for two more in August. A commemorative plaque was unveiled at Stagg Field on 2 December 1952, the occasion of the tenth anniversary of CP-1 going critical. It read as follows: The plaque was saved when the West Stands were demolished in August 1957. The site of CP-1 was designated as a National Historic Landmark on 18 February 1965. When the National Register of Historic Places was created in 1966, it was immediately added to that as well. The site was also named a Chicago Landmark on 27 October 1971. Today the site of the old Stagg Field is occupied by the university's Regenstein Library, which was opened in 1970, and the Joe and Rika Mansueto Library, which was opened in 2011. A Henry Moore sculpture, Nuclear Energy, stands in a small quadrangle outside the Regenstein Library on the former site of the west viewing stands' rackets court. It was dedicated on 2 December 1967, to commemorate the 25th anniversary of CP-1 going critical. The commemorative plaques from 1952, 1965 and 1967 are nearby. A graphite block from