A behavioral health unit (BHU) is a program that includes a separate housing location within a correctional facility designed to address the corrections-based therapeutic treatment of inmates currently diagnosed with a serious mental illness who, due to their behavior, would otherwise be serving a confinement sanction in a SHU or separate keeplock housing unit. These inmates have displayed a marked inability to conform their behavior to societal and/or institutional standards of conduct. They present with a complex interplay of antisocial behaviors and psychological factors that have resulted in their not having benefited from habilitation efforts in the community or rehabilitation efforts during a series of institutional placements. The unit is designed to meet the therapeutic needs of these inmates, while maintaining adequate safety and security on the unit. Although a BHU is not operated as a disciplinary housing unit, in light of the security concerns associated with the behaviors that resulted in their confinement and other sanctions, inmates on the unit are subject to limitations on the quantity and type of property they are permitted to have in their cells and are afforded access to programs that are more restrictive than those afforded general population inmates, in order to maintain security and order on the unit. After a brief orientation period and absent exceptional circumstances, in addition to exercise, inmates housed in a BHU are offered four hours of structured out-of-cell therapeutic programming and/or mental health treatment on a daily basis, excluding weekends and holidays; provided, however, the department may maintain housing for 38 BHU inmates who are offered two hours rather than four hours of structured out-of-cell therapeutic programming and/or mental health treatment. The therapeutic behavioral unit (TBU) is the functional equivalent of the BHU for female inmates.