27 C.F.R. § 19.704 – Security.

(a) General. The proprietor of an alcohol fuel plant must provide adequate security measures at the alcohol fuel plant in order to protect against the unauthorized removal of spirits.
(b) Storage. The proprietor must store spirits in a building or a storage tank, or within an enclosure, that will be kept locked when operations are not being conducted.
(c) Additional security. The appropriate TTB officer may require additional security measures for the premises if the alcohol fuel plant's security is found to be inadequate. The additional measures required may depend upon past security problems experienced at the alcohol fuel plant, the volume of alcohol produced, the risk to tax revenue, and any safety requirements. Additional security measures may include, but are not limited to:
1. (1) A fence around the alcohol fuel plant;
2. (2) Flood lights;
3. (3) A security or alarm system;
4. (4) A guard service; or
5. (5) Locked or barred windows.
  (26 U.S.C. 5178, 5202)