O & P Wings on January 30, 1950.  The P Wing section is only three stories.  From The First Quarter Century 1925-1950, page 74.

Wing O under construction-April 8, 1949-showing the Radioactive "Hot" Laboratory for the Atomic Energy Commission Project. From The First Quarter Century 1925-1950, page 73.	January 1951 view of O and P Wing	December 1961 view showing the P Wing infill.	O and P Wings after the P Wing infill was completed, from A brief history of the University of Rochester Atomic Energy Project from 1943-1968, by Henry Alexander Blair

The Manhattan Project was transferred from the War Department to the new Atomic Energy Commission on January 1,  1947.  Funds were appropriated in 1947 for the Commission to build and equip a medical and biological training and research center, which became the O Wing and included a tunnel under Elmwood Avenue that connecting to the new building to the east end of the Medical Center Annex.   The O Wing was 45 feet side and 150 feet long.  The U.S. Public Health Service provided additional funding to build a 100-foot long, three-story high, structure known as P Wing that would connect the O Wing to the existing building. The combined wings were completed in February 1950. 

Three floors were added to in P Wing in 1958, giving the entire wing a uniform height of six stories plus a basement.  A small addition was built on top of O Wing in 1965 to connect to the seventh floor of the new OO Wing. 

References
1948 Third Semiannual Report of the Atomic Energy Commission, February 2, 1948
Page 17:  Authorization of funds for building and equipping a medical and biological training and research center at the University of Rochester, Rochester, N.Y.
These new facilities will permit the extension of the medical and biological research program conducted for the Government at this institution and particularly the work now being done under contract with the Commission, centering around the Medical and biochemical aspects of radioactive substances and processes.

1948 "Work Set by UR This Fall on 2 U.S. Medical Projects," Democrat and Chronicle, September 3, 1948, Page 22.
Atomic Energy Commission [O wing, 6 stories, 5700] and Cancer Study Wing [P wing, 3 stories, 5500]

1949 City Council Meeting, Democrat and Chronicle, April 29, 1949, Page 39.
Authorization to Grant License or Permission to the University of Rochester to Construct and Maintain Tunnel under Elmwood Avenue.

1950 The First Quarter Century 1925-1950  
Page 11:  The new wing for cancer research, therapy and teaching connects the Atomic Energy Project north wing with wings K and L of the main building, and will be devoted to clinical and experimental work in this important field. It was built with funds provided by the U. S. Public Health Service.
Page 72:  In 1948 the Commission approved establishment of a training program at Rochester for students of various phases of the health and biological aspects of atomic energy development. This involved construction of a new wing on the north side of the Medical School, 45 ft. wide, 150 ft. long and seven stories high including the basement. Completed in February, 1950, this building is designed to accommodate 50 to 100 students.
Page 75:  Although considerable collaboration in research with other departments of the College and the Medical School has taken place since the war, it is anticipated that this will increase. For example, an arrangement was made, with the approval of the Commission, for the Divisions of Radiation Therapy and Cancer Research to occupy space in the new AEC building. It is hoped that this arrangement will facilitate co-operation of mutual benefit to the groups concerned, both in the teaching of students and in the applications of new techniques with radioactive materials to research and therapy.

1951 Ninth Semiannual Report of the Atomic Energy Commission, January 1951
Pages 13-14:  Particle Accelerator Program.  Similar machines are nearing completion at the University of Chicago and the Carnegie Institute of Technology, and a slightly smaller one was completed at the University of Rochester in late 1948.  These four accelerators have been jointly financed by the AEC and the ONR.
Page 16:  New Buildings and Equipment.  University of Rochester. AEC Training Building, estimated total cost 1.3 million dollars; completed and in use.

1952 Graduate training programs at the University of Rochester Atomic Energy Project, by J. Newell Stannard

1954 Graduate training programs at the University of Rochester atomic energy project, by H.A. Blair and J.N. Stannard.

1957 Graduate training programs at the University of Rochester Atomic Energy Project, by Henry A. Blair

1968 A brief history of the University of Rochester Atomic Energy Project from 1943-1968, by Henry Alexander Blair
Page 10:  As mentioned above, the building occupied by the Department on the north side of Elmwood Avenue is called the Medical School Annex, or just the Annex. It now consists of three wings, A, B, and C. Wing A, 9700 sq. ft., was constructed in 1942 by the University to house high voltage X-ray equipment for testing castings for the Armed Forces as previously mentioned. Wing B, originally 15,000 sq. ft., and Wing C, originally 19,000 sq. ft., were built by the Manhattan District in 1943 and 1944. Education space, O Wing, 53,000 sq. ft., was built by the Commission as an addition to the Medical School in 1950. A tunnel under Elmwood Avenue connects this building to the Annex. Additions to B Wing of the Annex have been: the Alpha Laboratory , 6,000 sq. ft., in 1952; a third floor, 5,200 sq. ft., in 1961; and a low level counting facility, 600 sq~ ft., in 1964. In 1951 900 sq. ft. were added to C Wing for flash burn studies. A radioactive storage vault, 200 sq. ft., was constructed off the tunnel joining the Annex and the Medical School in 1961. All of these additions were built by the Atomic Energy Commission. During 1965 and 1966 additions to O Wing of the Medical School totaling 50,000 sq. ft. were constructed. These consisted of an underground radiation facility off the tunnel and an eight-story building, OO Wing, adjoining O Wing and containing laboratories and lecture rooms

1975 To each his farthest star:  The University of Rochester Medical Center -1925-1975, edited by Edward C. Atwater and John Romano.

© 2021 Morris A. Pierce