Building History Click image for low-res file   CO-83-X-1 – View looking southwest at Building 121, the plant security building. Building 121 was one of the original structures at the Rocky Flats Plant. It shared a common wall with Building 122, the emergency medical building. (7/29/52) (Hi-res [300 dpi]) CO-83-X-2 – View looking southeast at Building 121. The building housed offices, the Rocky Flats Plant central alarm station, alarm consoles, the armory, the lock and key section, a computer room, a utility room, and locker rooms with showers. (1/98) (Hi-res [300 dpi])