subdued by guards with tear gas, shotguns, and rifles. 1100 Rebels were confined to a baseball diamond without food or water, with Warden Gladden saying they would stay there until "I am sure they are repentant". They stayed on the diamond for two days and one night, until twenty ringleaders identified by prison authorities were surrendered, and prisoners agreed to be individually searched. In what may have been the first sex reassignment surgery officially conducted in a prison, a DMAB prisoner changed her sex to female, through surgery and hormones, in a period prior to release in 1965. Discontent continued in the 1960s. The public became aware that only 200 of the 1200 inmates at OSP actually had sentences calling for maximum security incarceration; yet all inmates were treated according to maximum security standards. Prisoners continued to complain about medical care, dental care, and visitation rights. Unrest culminated in March 1968, in an uprising which began with a surprise takeover of the prison's control center. 700 prisoners took control of the facility, started a fire in the flour shop, and held 40 guards and prison employees hostage. The hostages were freed after prison officials announced the resignation of Warden Gladden (then 73 years old), as well as immunity for the rioters. Prisoners were criticized for damaging facilities that supported them. Ron Schmidt, press secretary of Governor Tom McCall, said: "It's pure devastation. The men destroyed everything that was of any benefit to them." Two inmates were stabbed during the riot: Delmar DuBray, 30, was stabbed in the right kidney; Melvin Newell, 36, was stabbed in the abdomen and groin. In November 1968, a work stoppage by 81 prisoners in the laundry room was controlled by guards with clubs, and the prisoners placed in isolation Also in 1968, OSP inmates founded UHURU, an organization dedicated to Afro-American culture, history, and community service. Although the prison establishment was skeptical at first, UHURU gained official support and had a membership of several hundred in 1982. OSP prisoners were politically active in the following decades, holding forums on politics and communicating with the Oregon NAACP. OSP began to recruit African American staff in 1981 in response to pressure from activist black prisoners. In September 1988, 28 female inmates at the Oregon Correctional Center staged a sit-down protest that prison Superintendent Robert H. Scheidler described as the first of its kind in the facility's history.