28 CFR §541.41

1. (a)The Warden shall submit a recommendation for referral of an inmate for placement in a control unit to the Regional Director in the region where the inmate is located.
2. (b)The Warden shall consider the following factors in a recommendation for control unit placement.
   1. (1)Any incident during confinement in which the inmate has caused injury to other persons.
   2. (2)Any incident in which the inmate has expressed threats to the life or well-being of other persons.
   3. (3)Any incident involving possession by the inmate of deadly weapons or dangerous drugs.
   4. (4)Any incident in which the inmate is involved in a disruption of the orderly operation of a prison, jail or other correctional institution.
   5. (5)An escape from a correctional institution.
   6. (6)An escape attempt. Depending on the circumstances, an escape attempt, considered alone or together with an inmate's prior history, may warrant consideration for a control unit placement.
   7. (7)The nature of the offense for which committed. An inmate may not be considered solely on the nature of the crime which resulted in that inmate's incarceration; however, the nature of the crime may be considered in combination with other factor(s) as described in paragraph (b) of this section.
3. (c)The Warden may not refer an inmate for placement in a control unit:
   1. (1)If the inmate shows evidence of significant mental disorder or major physical disabilities as documented in a mental health evaluation or a physical examination;
   2. (2)On the basis that the inmate is a protection case, e.g., a homosexual, an informant, etc., unless the inmate meets other criteria as described in paragraph (b) of this section.