The purpose of this publication is to provide a basic understanding of the on-site radiation exposures at Hanford and how they differed from exposures beyond the Hanford site. This information has been prepared to respond to questions from military veterans who were stationed at Hanford, as well as former Hanford construction workers and their families.
This publication describes the unique exposure situation of military personnel stationed at
Camp Hanford and of Hanford construction workers. Please note, however, that the on-site exposures discussed below do not include occupational exposures to workers inside Hanford facilities. Also included here is an overview of the ongoing work by the Hanford Environmental Dose Reconstruction (HEDR) Project relating to on-site exposures.
Uniqueness of On-Site Exposures
The exposures to people on the Hanford site were different from the exposures received
by people outside Hanford�s boundaries. People who lived and worked off-site received
most of their exposure through food that was contaminated by radioactivity released from
Hanford. (See HHIN�s The Release of Radioactive Materials from Hanford: 1944-1972 for information about the radionuclides released and how people off-site were exposed.) People who lived or worked on-site were exposed also through direct, external radiation
exposure and through inhaling radioactive materials.
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Hazardous Chemicals This publication does not address hazardous chemicals released from Hanford. Hazardous chemicals, such as nitrous oxide and carbon tetrachloride, were released into the air from various stages of producing and refining plutonium for use in nuclear weapons. However, HHIN�s Congressional mandate limits us to addressing the radioactive materials released from Hanford from 1944 to 1972. |
Second, because on-site personnel were closer to Hanford�s production plants that released radioactive material into the environment, they were exposed to larger particles that carried a higher amount of radioactivity. These larger, heavier particles fell to the ground more quickly than lighter particles. Lighter particles, by contrast, could have been carried by the wind for longer distances.
Third, people on-site were exposed to radionuclides that had shorter half-lives. The half-
life is the amount of time it takes for a radioactive substance to decay and lose one-half of
its radioactivity. Radioactive materials with very short half-lives would have lost all or
most of their radioactivity by the time they reached as far as the Hanford boundaries.
On-site exposures were unique not just because of the radioactive materials involved but because of the particular situations of different groups of on-site workers. These groups of workers were: military personnel, people stationed in guard towers, construction workers, workers who drilled wells, and the power company employees who worked at the Midway electrical power substation.
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Military Personnel
From the start of Hanford�s operations and continuing until the early 1960s, military personnel were involved with providing security for the site. Assisted during World War II by the Army�s G-2 intelligence group, Military Police (MPs) from the Army provided security at Hanford from 1944 until April 1947. In April 1947 the new Atomic Energy Commission (AEC) transferred responsibility to the security force of General Electric, which was then the contractor operating Hanford.
During the spring and fall of 1948, troops from Fort Lewis were sent to Hanford on �prolonged maneuvers.�1 In March 1950, the Army began to station troops there permanently to operate 16 anti-aircraft gun emplacements. In 1951 the Army officially designated it �Camp Hanford� (see map). Later on, the anti-aircraft guns were replaced by Nike missiles. Camp Hanford was deactivated in 1960. From 1952 until the military�s presence at Hanford ended in 1962, over 14,000 military personnel had served at Hanford.
What makes the exposure of Hanford�s soldiers different from the exposure of other workers is that soldiers� exposure was not limited to their work hours. For years, soldiers not only worked on-site but also ate and slept there. In her book, On the Home Front, Michele Gerber writes, �They slept out overnight on the atomic reservation, often in open- air tents or hastily built huts and barracks.� 2 Additionally, since Hanford�s soldiers patrolled the desert in open-air jeeps, they could have inhaled radioactive particles that were present in the dust.
There is little reference in historical Hanford documents to the on-site exposures of
military personnel. The references that do exist suggest that military personnel were
exposed to higher routine levels than any other Hanford workers. One such reference is
from Herbert Parker, Hanford�s chief radiation protection official. In 1951, he wrote, �It is
found that the encampment near the 200-E Area (position 40 on the map) is in the
�hottest� area.�3 Later in the same document, Parker described this encampment as the only one �in a suspect zone.� However, Parker pointed out that even at this encampment, the external
exposure rate was well below the (1951) permissible limit for personnel at Hanford.4
Personnel in Guard Towers
People who were stationed in the guard towers, especially in the location called the �200
Area� (see map), could have been exposed in unique ways. For example, the exhaust
plumes from the separations plants would sometimes be blown directly into one of the
guard towers. Any security personnel on duty at the time would have been exposed
externally as well as through inhalation. In the late 1940s, when there were problems with
hot (radioactive) particles, a Hanford engineer who designed emissions filters remembered
his concern about the security personnel: �I suggested that [Hanford officials] reveal to
everybody what the situation was, and have them wear respirators; my group wore
them.... But they didn�t tell anybody....�5 (See �Current Scientific Work Concerning On-
Site Exposures,� below, for more information on hot particles.)
Construction Workers
Construction workers would have been exposed to Hanford�s radioactive releases on any outdoor construction project after September 1944 in the 100 areas and after December 1944 in the 200 Areas (see map). Some of the major construction projects were the production reactors (100 Areas) and the following 200 Area facilities: the tank farms (containers for storage of high-level waste), the Plutonium Finishing Plant (PFP, completed in 1949, located in the 200 West Area), the Reduction Oxidation Plant (REDOX, completed in 1952, located in the 200 West Area) and the Plutonium-Uranium Extraction Plant (PUREX, completed in 1956, located in the 200 East Area).
Although other Hanford workers were given filter masks during certain times when
Hanford had particle problems (1947-1951 and 1952-1954), construction workers were
not given protective masks.
Well-Drilling Crew
Other Hanford workers drilled wells in order to take samples to test for contamination of
groundwater by wastewater from separations plants. Some workers recall being sprayed
wit the contaminated water. Several people have called HHIN saying they had fallen ill
after such exposures, including two who had lymphoma.
Power Substation Crew
While not part of the Hanford work force, employees of the Bonneville Power
Administration (BPA) worked at the Midway electrical power substation located near
Army Position 71 (see map) in the northwest corner of the Hanford site. A crew lived at
the substation year-round. Because of their location, their exposures would have been
similar to those of other on-site workers.
Current Scientific Work Concerning On-Site Exposures
The HEDR Project was established to estimate what radiation dose people living near Hanford some time between 1944 and 1992 might have received from releases of radioactive materials. (For more information about HEDR�s work, see HHIN�s The Release of Radioactive Materials from Hanford: 1944-1972.) One of the HEDR tasks remaining to be completed is estimating doses for on-site personnel. There are three main activities to be done for this HEDR task.
1. Identify and acquire original Hanford documents about: (a) the releases of radioactive particles, and (b) radionuclides with short half-lives, such as iodine-132 and certain radioactive gases.
Regarding radioactive particles, there were two periods during Hanford�s operations when there were major particle releases. From late 1944 to at least 1951, Hanford released particles containing plutonium, strontium and cerium. From 1952 to 1954, particles of ruthenium were released into the air. (For more information, see HHIN�s Potential Health Problems from Exposure to Selected Radionuclides: Plutonium, Strontium, Cerium and Ruthenium.)
Short-lived radionuclides release energy (�decay�) rapidly. For example, the half-life of iodine-132 is about two hours. Because of this rapid decay, the material would have lost all, or nearly all, of its radioactivity before exposing someone who drank contaminated milk.
2. Determine the radionuclides that would have likely posed the greatest danger to on- site personnel.
A �source term� of these radionuclides will be developed � that is, an estimate will be prepared of how much radioactive material was released from the Hanford operations into the air.
The remaining HEDR work may need to reconsider releases from such facilities as the PFP, also known as Z-Plant (located in the 200 West Area). HEDR spent little time evaluating this facility during its study of off-site exposures.6 Because PFP dealt with plutonium metal, it could have been a source of particles. Of particular interest is the 232-Z Building at PFP in which plutonium-contaminated wastes were incinerated from 1961 to 1972. There were also several plutonium fires within PFP. Some of these resulted in releases to the atmosphere.7
3. Perform �screening calculations� to help determine which radionuclides contributed
the most to dose. Screening calculations are rough dose estimates to help assess if the
doses are high enough to warrant additional work. By reviewing these rough estimates,
state and federal officials will have the information necessary to decide if the exposure
levels are high enough to justify more detailed (perhaps even individualized) dose
estimates. (For more information on dose and the potential health effects of radiation
exposure, see HHIN�s An Overview of Hanford and Radiation Health Effects.)
To learn where your Army unit was stationed you can write to:
Department of Army
Freedom of Information and Privacy Act Office
ATTN: T.A.P.C.-P.D.R.-P.F.
125 Jefferson Davis Highway, Suite 201
Arlington, VA 22202-4102
1. Michele Stenehjem Gerber, On the Home Front: The Cold War Legacy of the Hanford Nuclear Site (Lincoln, Neb.: University of Nebraska Press, 1992) p. 104.
The Dragon�s Tail: Radiation Safety in the Manhatten Project, 1942-46, Barton C. Hacker (University of California Press, Berkeley, Calif.1987) A description of how scientists and doctors first sought to cope with the known and unknown hazards of nuclear energy, based on original documents and extensive interviews.
Elements of Controversy: The Atomic Energy Commission and Radiation Safety in Nuclear Weapons Testing 1947-1974, Barton C. Hacker (University of California Press, Berkeley, Calif. 1994) An account of America�s nuclear weapons testing program and its effects, based on the Atomic Energy Commission�s documentary record and the scientific literature of radiation health effects.
On the Home Front: The Cold War Legacy of the Hanford Nuclear Site, Michele Stenehjem Gerber (University of Nebraska Press, Lincoln, Neb. 1992).
U.S. Department of Energy (USDOE) Open Net Database. Provides access to recently declassified information, including information declassified in response to Freedom of Information Act requests.
