The Oregon State Penitentiary in Salem is on lockdown today and all inmate visiting hours have been canceled due to a Sunday afternoon fight involving approximately 75 inmates in the prison's recreation building. Prison Officials responded to a fight involving several inmates inside the building, and while breaking up that altercation, 75 other inmates went outside to the recreation yard and started another fight. Officers fire one warning shot and used chemical spray to get things back under control. Only minor injuries were reported.