A values-centered and team-based behavioral safety process was implemented in a petroleum oil refinery. Employee teams defined the refinery's safety values and related practices, which were used to guide the process design and implementation. The process included (a) a safety assessment; (b) the clarification of safety-related values and related practices; (c) process design and executive overview; (d) safety-observation training; (e) feedback, recognition, and celebration; and (f) process maintenance. Data that span 20 years are presented to show the long-term impact on recordable incidents, lost-time cases, and direct costs of injuries. The implementation was associated with an 81% decrease in recordable incidents, a 79% decrease in lost-time cases, and a 97% savings in annual workers' compensation costs over an eight-year period. An interview with the vice president of the refinery is presented to highlight the process's influence on the refinery's safety culture. (Contains 1 table, 6 figures, and 1 note.)