Therapeutic communities (TC's) are emerging as one of the primary approaches for treating substance abuse for criminal offenders. However, the achievement of positive TC outcomes is predicated on their successful implementation. This study applied a multimethod approach to assessing the effect of a smoking ban and changing treatment providers on the implementation of the prison-based therapeutic community substance abuse treatment program (TCSATP). It incorporates the views of inmates and prison staff members through focus groups with staff members and telephone interviews with inmates 12 months after release from the TCSATP prison. The smoking ban led to a loss of inmates' focus on treatment goals and strained inmate-custody staff relationships, whereas the change in treatment providers resulted in an immediate turnover of one-third of the counselors and a disruption of relationships between custody and treatment staff. The article claims that these findings illustrate the difficulties prisons face as they try to maintain well-developed TC programs over time. It is inevitable that situational events will occur that can negatively affect the program. Finally, this study illustrates that the negative effect of situational events on prison-based TC programs can be time limited and appropriately dealt with at the administrative level. Tables, references