28 CFR 501.2 - National security cases.
(a) Upon direction of the Attorney General, the Director, Bureau of Prisons, may authorize the Warden to implement special administrative measures that are reasonably necessary to prevent disclosure of classified information upon written certification to the Attorney General by the head of a member agency of the United States intelligence community that the unauthorized disclosure of such information would pose a threat to the national security and that there is a danger that the inmate will disclose such information. These special administrative measures ordinarily may include housing the inmate in administrative detention and/or limiting certain privileges, including, but not limited to, correspondence, visiting, interviews with representatives of the news media, and use of the telephone, as is reasonably necessary to prevent the disclosure of classified information. The authority of the Director under this paragraph may not be delegated below the level of Acting Director.
(b) Designated staff shall provide to the affected inmate, as soon as practicable, written notification of the restrictions imposed and the basis for these restrictions. The notice's statement as to the basis may be limited in the interest of prison security or safety or national security. The inmate shall sign for and receive a copy of the notification.
(c) Initial placement of an inmate in administrative detention and/or any limitation of the inmate's privileges in accordance with paragraph (a) of this section may be imposed for a period of time as determined by the Director, Bureau of Prisons, up to one year. Special restrictions imposed in accordance with paragraph (a) of this section may be extended thereafter by the Director, Bureau of Prisons, in increments not to exceed one year, but only if the Attorney General receives from the head of a member agency of the United States intelligence community an additional written certification that, based on the information available to the agency, there is a danger that the inmate will disclose classified information and that the unauthorized disclosure of such information would pose a threat to the national security. The authority of the Director under this paragraph may not be delegated below the level of Acting Director.
(e) Other appropriate officials of the Department of Justice having custody of persons for whom special administrative measures are required may exercise the same authorities under this section as the Director of the Bureau of Prisons and the Warden.