28 C.F.R. § 0.144
The Director of the Federal Bureau of Investigation, Director of the Bureau of Prisons, Commissioner of Federal Prison Industries, Inc., Commissioner of the Immigration and Naturalization Service, Administrator of the Drug Enforcement Administration, Director of the Bureau of Alcohol, Tobacco, Firearms, and Explosives, Director of the Office of Justice Assistance, Research and Statistics, Director of the Executive Office for United States Attorneys and Director of the United States Marshals Service, as to their respective jurisdictions, and the Assistant Attorney General for Administration, as to all other organizational units of the Department, are authorized to exercise the authority vested in the Attorney General by 5 U.S.C. 6101(a) , to determine that the organizational unit concerned would be seriously handicapped in carrying out its functions or that costs would be substantially increased except upon modification of the basic workweek, and when such determination is made to fix the basic workweek of officers and employees of the unit concerned.
28 C.F.R. §0.144