(a) You must prevent, and minimize the possibility for, livestock and unauthorized people from entering the active portion of your facility.

(b) Your facility must have:

(1) A 24-hour surveillance system (for example, television monitoring or surveillance by guards or facility personnel) that continuously monitors and controls entry onto the active portion of the facility; or

(2) An artificial or natural barrier (for example, a fence in good repair or a fence combined with a cliff) that completely surrounds the active portion of the facility; and

(3) A means to control entry, at all times, through the gates or other entrances to the active portion of the facility (for example, an attendant, television monitors, locked entrance, or controlled roadway access to the facility).

(c) You must post a sign at each entrance to the active portion of a facility, and at other prominent locations, in sufficient numbers to be seen from any approach to this active portion. The sign must bear the legend “Danger—Unauthorized Personnel Keep Out.” The legend must be in English and in any other language predominant in the area surrounding the facility (for example, facilities in counties bordering the Canadian province of Quebec must post signs in French, and facilities in counties bordering Mexico must post signs in Spanish), and must be legible from a distance of at least 25 feet. You may use existing signs with a legend other than “Danger—Unauthorized Personnel Keep Out” if the legend on the sign indicates that only authorized personnel are allowed to enter the active portion, and that entry onto the active portion can be dangerous.