Robert Oppenheimer's Q Clearance was taken away from him in 1954. He had been given a Q Clearance in 1947. Nothing new had surface against him since that time. More details on this memo are on p.425 of the hearing. Oppenheimer's attorney's were Lloyd K. Garrison and Samuel Silverman. Atomic Energy Commission attorneys were Roger Robb and C. Arthur Rolander. Gordon Gray was the Chairman of the Personnel Security Board. The hearing was held in strict secrecy and Oppenheimer's attorney's office was bugged. Note how Oppenheimer's attorney Garrison is trying to get to the bottom of the relationship between the AEC and the FBI and wants to view the minutes of the meeting that granted Oppenheimer his Q Clearance in 1947, the memo is sent to William Uanna.  A good book on the hearing is THE RUIN OF J. ROBERT OPPENHEIMER by Priscilla J. McMillan. Oppenheimer's removal from the AEC had a demoralizing effect on the U.S. scientific community.
Personnel Security Board Gordon Gray Chairman
U.S. Atomic Energy Commission 1954