Workplace aggression can escalate from verbal to physical, adding risk of physical injury to negative psychological impact. Understanding escalation is necessary to develop effective violence intervention/prevention programs, but its occurrence is not well documented. An online survey determined if and how aggression escalates in occupational therapy (OT) workplaces. Because local culture can influence workplace events we compared surveys from northeastern states with the lowest rates of homicide to southeastern states with the highest. Ninety four OTs working in southeastern or northeastern states reported details of the most recent verbal and/or physical aggressive event initiated by clients (NIOSH Type 2) or staff (NIOSH Type 3) they witnessed or experienced in the workplace within the last year. Aggressor status, motivation, actions; therapist reactions, injuries and psychological sequelae were queried in logical order. Behavior inter-correlation followed by cluster analysis determined if levels of escalation could be detected. Analyses grouped events into five escalation levels in which progressively more hostile or damaging behaviors were added at each successive level. Higher levels involved known risk factors: Younger, reactively angry clients with prior aggression histories escalated attacks to involve restraint, calls for help and physical injury. Southeastern aggressor/target interactions appeared more combative, seemingly regardless of personal risk. Remarkably, northeastern OTs reported significantly more positive and fewer negative feelings across levels of escalation. OT workplace aggression occurs frequently, can escalate to injurious levels and requires prevention/intervention. How therapists maintain positive attitudes in the face of violence deserves further study.