Rocky Flats Plant, Guard Facility
HAER No. CO-83-G
(Rocky Flats Plant, Building 120)
Note: The documentation for Building 120 also represents other access guard
facilities, including Buildings 100, 113, 133, 900, and 920.
Rocky Flats Environmental Technology Site, Highway 93, Golden, Jefferson
County, Colorado. Building 120 is located on the south side of the West (access) Road,
approximately 2,323 feet east of the intersection of Colorado Highway 93 and the West Road.
This building is a primary contributor of the Rocky Flats Plant
historic district, and is associated with the U.S. strategy of nuclear military deterrence
during the Cold War, a strategy considered of major importance in preventing Soviet
nuclear attack. Building 120 is one of two guard facilities used by security personnel to
control access to the site.
Building 120 is a hexagonal structure with windows on four sides. The
exterior walls are concrete block, and the interior walls are gypsum board. The dimensions
are approximately 18 feet along the north wall, 15 feet along the northeast wall, 18 feet along the
southeast wall, 14 feet along the south wall, 18 feet along the southwest wall, and 15 feet along the
northwest wall. Three guard booths to the north of the structure are on raised islands.
Each guard booth is equipped with a traffic control barrier. Building 120 has a stand-by
generator with a 2,000-gallon underground storage tank for diesel fuel, which is located
south of the building.
Building 100, built in 1969, is four-sided and approximately 430 square feet. It is
located approximately 550 feet southeast of Building 131 and is situated in the middle of the
intersection of West Road, Cactus Avenue, and First Street. Building 113, built in 1988,
is four-sided and 65 square feet. It is located west of the intersection of Fourth Street
and Central Avenue. The structure was used to control access to the Department of
Energy/Rocky Flats Field Office and the managing and operating site contractors
headquarters. Building 133, built in 1986, is four-sided and 32 square feet. It is located
on the roadway at the entrance to Building 130, the 130 Warehouse, and the adjacent
parking areas. Building 900, built in 1964, is four-sided, approximately 320 square feet.
It is located approximately 300 feet southeast of Building 901 (guard tower) in the middle of
Central Avenue and East (access) Road. Building 920, built in 1986, is six-sided,
approximately 560 square feet. It is approximately 1,500 feet west of the intersection of
Indiana Street and the East Road on the north side of the roadway. Building 920 housed
personnel responsible for controlling access to the site from the east access point.
Since 1951, the West Road has been the primary entry point to the Rocky
Flats Plant site, and the only access until 1964. Building 120 was built to house the
protective force personnel responsible for controlling pedestrian and vehicle entrance to and egress
from the Rocky Flats Plant. Visitors and deliveries to the site had to enter through the
When the Rocky Flats Plant first opened, workers parked west of the site on Highway 93
and were bused to the administration area (Building 11, later changed to Building 111) to
check in, and then walked or were bused to their respective work buildings. Shortly after
the Rocky Flats Plant opened, two parking lots were built outside the fenced plant
operations area. One parking lot was located west of Building 11 (111). Employees parked
in this lot and entered the site through Building 11 (111). A second parking lot was
located just west of Building 81 with Guard Post 864 as the check-in point.
By 1958, employees working in Buildings 71 (771) and 91 (991) were allowed to drive
their personal cars onto the plant property through a gate near Building 81 (881)
(Riddle). In 1961, work shifts were increased from one shift, five days a week to
multiple shifts, seven days a week in order to keep up with production demands (Weaver).
By the spring of 1962, there were 2,100 employees at the site, an increase from 1,435
employees in September of 1961 (Weaver). In 1964, an east access route from Indiana Street
was built with a guardhouse, Building 900, to check employee badges as they entered the
plant. Employees entering from the west were still required to park outside the fence or
enter through the gate near Building 81 (881) until 1969, when Building 100 was built as a
western badge check point (Riddle).
In the 1970s and 1980s, plant security personnel were concerned less with espionage and
more with the threat of terrorism and infiltration of the plant by protestors. Better
protection of the outer boundaries of the area became necessary. In 1972 a buffer zone of
4,600 acres around the existing plant was purchased for additional protection. In 1985,
Building 120 was built to control site access from the western edge of the buffer zone.
United States Department of Energy. Site Safety Analysis Report,
Notebook 13-Security (1995), by EG&G Rocky Flats, Inc. Rocky Flats Repository.
Golden, Colorado, 1995.
United States Department of Energy. Final Cultural Resources Survey Report (1995), by Science Applications International Corporation. Rocky Flats Repository. Golden,
Riddle, Robert, employed at the plant by the site contractor since 1958.
Weaver, Jack, employed at the plant by the site contractor since 1961.
Personal communication, August 1997.
D. Jayne Aaron, Environmental Designer, engineering-environmental
Management, Inc. (e2M), 1997. Judith Berryman, Ph.D., Archaeologist, e2M,
Index to Photographs
Building 120 is located on the south side of the West (access) Road, approximately
2,323 feet east of the intersection of Colorado Highway 93 and the West Road, Golden Vicinity, Jefferson County, Colorado.
Photograph by Timothy McGrath and Katherine T. Abeyta, Source One, site photography
contractor, summer 1997.
CO-83-G-1 – View looking east at the west elevation of Building 120. Building 120 houses the protective force personnel responsible for controlling entrance to and egress from the Rocky Flats Plant west entrance.