Document 51: Excerpt from Legend and Legacy
Michele Gerber, Legend and Legacy: Fifty Years of Defense Production at the Hanford Site (Richland, Wash.: U.S. Department of Energy Office of Environmental Restoration and Waste Management, 1992).
Why Hanford's History Is Important
Today, the Hanford Site is engaged in the largest waste cleanup effort ever undertaken in human history. That in itself makes the endeavor historic and unique. The Hanford Site has been designated the "flagship" of Department of Energy (DOE) waste [treatment efforts]. And, just as the wartime Hanford Project remains unmatched in history, no counterpart exists for the current waste cleanup enterprise.
The Hanford production mission generated two-thirds of all the nuclear waste, by volume, in the DOE complex. Nuclear waste is part of [Hanford's] history and legacy. We have been challenged to clean up that waste in the next three decades. Remaining mindful of the history that has shaped today's Hanford Site will help us define tomorrow's Hanford Site. . . .
During the year this document was written and compiled [1991-92], the world witnessed some of the most historic events of our century. National leaders of the U.S.S.R. renounced the Communist Party. The central, monolithic control that had existed in that country since the Communist revolution of 1917 was abandoned in favor of a loose confederation of republics. Today, the new Soviet Union struggles to establish businesses and distribution systems that work as it forges wholly new political parties. Both the United States and the U.S.S.R. announced the largest cuts in nuclear weapons ever undertaken. . . .
In a very real sense, the Hanford Site helped cause and allow these magnificent events to take place. Hanford, as the largest workhorse weapons production site in U.S. history, met a fearful challenge during the years since its founding in 1943. It made the weapons that ended World War II and that helped win the Cold War. Unlike other wars that were fought on battlefields, the Cold War was fought and won at Hanford, Washington, and at the other U.S. defense production sites.
Today, we, along with other Americans, reap the rewards. The Soviet Union's economy could not withstand the costs of the long years of weapons production, and it has to be totally restructured. That nation is discovering the benefits of democracy and peace. It has paid a very high price. While we do not gloat, and while we do want to help them rebuild, let's take time to be grateful for the monumental production history of the Hanford Site. Without it, the course of history today might be far different.
Site Selection Criteria and Hanford's Wartime Construction
The Hanford Site was selected for the location of the first, full-scale plutonium production plants in the world as the result of a series of important 1942-43 decisions. Soon after the Japanese attack on Pearl Harbor plunged the U.S. into war in December 1941, . . .President Franklin D. Roosevelt . . . charged the [Army] Corps [of Engineers] with constructing industrial plants that could produce uranium and plutonium. To accomplish this task, a new division, the Manhattan Engineer District (MED) was formed within the Corps in June 1942. In September . . . Leslie R. Groves was named to head the MED. . . .
The practical, tough-minded Groves has stated that he was frankly "horrified" [about the difficulties of making the plutonium needed for an atomic bomb. Plutonium did not occur in nature; it could only be manufactured by bombarding uranium with radioactive particles in a nuclear reactor.] Major uncertainties faced the plutonium project. The means of separating [plutonium from uranium] was [not known]. The equipment needed was not even designed or manufactured anywhere in the world as yet. And there was the question of maintaining health and safety in the presence of large quantities of new, dangerous, and poorly understood radioactive substances. Additionally, scientists could not even guess the amount of fissionable material [plutonium and uranium] needed to make each atomic bomb. Nevertheless, it was Groves' philosophy that "nothing would be more fatal to success than to try to arrive at a perfect plan before taking any important step." He tackled the practical questions: what materials would be needed? . . . where would the plants be located?
On December 14, 1942, [Groves] developed site criteria: The plutonium production facilities should be built on a large and remote tract of land, with a "hazardous manufacturing area" of at least 12 by 16 miles, space for laboratory facilities at least eight miles from the nearest pile or separations plant, no towns of 1,000 or more people closer than 20 miles from the hazardous rectangle, and no main highway, railway or employee village closer than 10 miles from it.
. . . An abundant, clean water supply was needed, as was a large electric power supply and ground that could bear heavy loads.
Three days later, [three army engineers] left to scout the western United States for such a site. When they had seen and explored the dusty tract lying between the towns of Hanford and Richland, Washington, they reported to General Groves that the place was "far more favorable in virtually all respects than any other." Groves, after a January visit, concurred, and land acquisition proceedings began. In August 1945, the first public report on the Manhattan Project issued by the War Department would affirm that the Hanford Site was selected partly for its "isolation."
Unprecedented Engineering and Construction Feat
Once the land had been procured, construction proceeded at a nearly unbelievable pace. In just the 30 months between groundbreaking in March 1943, and the end of the war in August 1945, the MED built 554 buildings not dedicated to living requirements. Among the most prominent of these were B, D and F Reactors; 64 underground, high-level waste storage tanks; and many facilities dedicated to [plutonium production] in the 300 Area. The Hanford Project also constructed 386 miles of automobile roadway, 158 miles of railroad, 50 miles of electrical transmission lines, and hundreds of miles of fencing. Additionally, it built a new "government city" of Richland, capable of housing 17,500 people. . . .
At wartime Hanford, secrecy reigned. Designs were compartmentalized, with only a few top engineers knowing the overall structure that a building would assume. Visiting MED scientists were given code names to veil their purpose and intent. In addition, uranium was called "base metal" and plutonium was called "product." . . . State and local officials were not informed about the purposes of the huge structures being erected in the desert, and even Vice President Harry S Truman was not informed until after Roosevelt had died! . . .
Postwar Production Lull (September 1945 August 1947)
The initial unveiling of the Manhattan Project in national press releases of August 6 and 7, 1945, brought a rush of reporters to Richland. They found an enthusiastic and dedicated group of war workers. Hanford Engineer Works commander Colonel Franklin T. Matthias described a "consciousness in the minds of people directly working on the Hanford Project that they have contributed to the mechanism that will certainly end the war very soon." The Japanese surrender on August 14, just five days after the bomb containing Hanford's plutonium was dropped on Nagasaki, produced "rejoicing" in Richland. The "atomic city's" victory celebrations were covered in newspapers and on radio programs throughout the nation, and the little city basked in admiration and praise. Matthias expressed local feelings succinctly: "We of the Hanford Engineer Works are proud of our job. We are proud of our community." Overall Manhattan Engineer District (MED) chief General Leslie R. Groves came in October to laud Hanford employees and to present the Army-Navy "E" Award, the highest civilian production commendation, to all of them. The War Department authorized "A-Bomb" pins, bearing mushroom clouds, to be given to all MED workers. . . .
Peaceful Use for the Atom
Despite the great mood of exhilaration and victory, early postwar Richland was as puzzled as the rest of the nation over what to do with the new power of atomic energy. Certainly, Richlanders were interested in pursuing peaceful uses for the awesome energy. . . . That spring [of 1946], the village sponsored its own "Win-The-Peace" contest, with speeches, symposia, and other public forums. A winning essay was written by Carolyn Hageman, the wife of a DuPont production engineer. She asked: "Are our hearts as big as our brains? . . . Our problem is how to make nuclear physics contribute to human comfort, human knowledge and hence to human dignity."
Where To Go from Here
Aside from the challenge of the peaceful atom, early postwar Richland, along with the rest of the United States, wondered whether the atomic plants would close, or how they would be administered if they remained open. President Harry S Truman . . . sought to formulate legislation to place atomic facilities under civilian control. Delays and Congressional wrangling characterized these efforts throughout 1946. General Groves has recalled: "With the ending of the war there was no national [atomic] policy. The only guidance that I could obtain was that I should continue to operate the project as I thought best." Throughout late 1945 and most of 1946, the MED adopted essentially a caretaker position. In fact, it instituted cost savings measures that reduced the output of fissionable materials [plutonium and uranium] at Hanford. Throughout the MED, much of the scientific research staff became discouraged by the lack of challenges and left. At Hanford, the number of contractor personnel fell by half, from 10,000 to 5,000, from September 1945 to December 1946.
During the same period, many government officials and members of the public began to worry about the confused state of U.S. atomic policy and slowed defense production. In 1946, William L. Borden, a young law student who later worked as an Atomic Energy Commission (AEC) official, published a small but influential book on defense strategy in the atomic age. In There Will Be No Time, Borden argued that atomic war would allow no time for defense preparations once hostilities had begun. He asserted that a national program of stockpiling weapons, a new and troublesome concept for many Americans, should begin immediately. His readable and quotable little book became immensely popular and prompted many citizens to write their Congressional representatives in favor of new arms production. At the same time, the MED's Advisory Committee on Research and Development, consisting of prominent scientists such as bomb developer J. Robert Oppenheimer, also became concerned. It proposed large research and development budget increases for 1947. Groves endorsed these increases. . . .
The Civilian Atomic Energy Commission
The new civilian AEC, finally formulated in the McMahon Atomic Energy Act of 1946, took control of the U.S. atomic complex, including Hanford, on January 1, 1947. Meeting early in the year after a whirlwind tour of the production sites and laboratories, the AEC's General Advisory Committee assigned its highest priority to weapons research and production. By February, improvement and expansion of the plutonium production units at Hanford topped the list of AEC goals. Concurrence on the need for such actions came from many high-level sources. The Joint Chiefs of Staff of the armed service branches declared in March that the weapons supply was "not adequate," and a solemn President Truman, conferring with AEC chairman David Lilienthal on April 2, agreed. In March, Truman "declared" the Cold War in a speech calling for military and economic aid to Greece and Turkey, countries he said were struggling against Soviet [aggression]. . . .
With national consensus mounting for more weapons production, the AEC made the decision to expand Hanford. In a series of spring  directives, the General Electric Company . . . was directed to build two new production reactors . . . as quickly as possible. . . . Richland residents expressed relief and joy that their important work would go forward. Tri-City businesses, which had been slumping, revived.
Hanford's First Postwar Expansion (1947-1949)
The expansion of the Hanford plants and the city of Richland that occurred from 1947-49 was the largest peacetime construction project in American history up to that point. It cost more than the original building of the Hanford Engineering Works from 1943-45 ($350 million compared to $230 million). . . .
New Production Capabilities
During this expansion, H and DR reactors were constructed, with operations beginning in October of 1949 and 1950, respectively. Z Plant, or the Plutonium Finishing Plant, also was built. . . . The Plutonium Finishing Plant made possible the [manufacture of] hockey puck-shaped [pieces of] plutonium metal, known as "buttons." . . . Forty-two additional high-level waste storage tanks were also constructed during this expansion, and the Hanford Works became unionized. . . .
Other key developments during the 1947-49 expansion concerned the city of Richland. At that time, Richland was strictly a government city. It actually was a part of the Hanford Works, and was a city where you had to live if you worked in Hanford operations, and where you could not live if you were not a permanent Hanford operations employee. During the 1947-49 expansion, the AEC built new housing on the west side of Richland, and the city grew from about 17,500 people to about 23,000. . . . Overall, the Tri-Cities population expanded to about 65,000 people during the 1947-49 expansion. . . .
Atomic Age Utopia
Richland "village" as it was known in the 1947-49 expansion period, was a busy and energetic place. By 1948, over 2,000 babies had been born at Kadlec Hospital, and the village had the highest birth rate in the nation! . . . Residents quickly formed a large number of professional and social clubs, and Richland became the first city in the U.S. to adopt a "sister city" in Europe on an ongoing, charitable basis.
Visitors were enchanted by the optimism and vigor of Richland. In 1949, Time magazine termed it a "model residential city...an atomic age utopia." Nevertheless, there were problems in the booming village. Some difficulties were mundane ones that affected any area beset by rapid development, and some were uniquely related to the atomic activities at the Hanford Works. There were frequent power outages as electrical transmission lines underwent constant expansion, and there was an acute housing shortage. Billowing construction dust was ever present. However, according to AEC records, [the dust sometimes contained] radioactive particulates. . . . [L]ocal officials undertook a vigorous tree and grass planting effort to anchor down the powdery [dust]. . . .
Cold War Grows Colder
Meanwhile, as Richland and the Hanford plants grew, the Cold War worsened. The Soviet Union precipitated a communist coup in Czechoslovakia and initiated a blockade of the city of Berlin in 1948. The U.S. responded with the Marshall Plan to aid economically unstable areas of Europe, and with the Berlin airlift (an 11-month ordeal). . . . That same year, President Truman was reelected on a platform that strongly advocated the "containment" of communism. Normally Republican Benton County supported the Democrat leader overwhelmingly. In 1949, the two "blocks" of nations, communist and non-communist, each formed mutual assistance pacts-the North Atlantic Treaty Organization in the case of the U.S. and its allies, and the Warsaw Pact in the case of the Soviet Union and its satellites. However, by late summer of that year , American officials were growing much more comfortable with the nation's state of defense readiness. Secretary of State Dean Acheson declared in July that the "position of the West. . . [has] grown greatly in strength, and that the position of the Soviet Union...has changed from the offensive to the defensive." Just two months later, Acheson and others would be confounded by an astonishing new development that would vastly alter the defense equation and would plunge the Hanford Works into another huge expansion.
First and Second Korean War Expansions (1950-55)
In September 1949, the American nation was shocked by the Soviet Union's detonation of its first atomic bomb. The Hanford Works, just having completed a huge expansion-the largest peacetime construction project in American history up to that point-was plunged into another major growth surge.
This expansion, lasting from 1950-52, received added impetus from other national and international developments that worried defense . . . experts. Within eight months of the Soviet blast, Mao Tse-tung's Communist forces succeeded in [conquering] mainland China. Quickly, Mao signed a mutual assistance pact with Soviet dictator Josef Stalin. On June 25, 1950, Communist North Korean forces crossed south of the 38th parallel and ignited the Korean conflict. The United States, quickly assuming a lead in international affairs, supplied 90 percent of the troops fighting North Korea. During the same period, some of the most well-known [atomic] spy cases in American history surfaced. . . . In [February] 1950, . . . Wisconsin Senator Joseph McCarthy launched four years of accusations that communists infested the American government and media.
Widespread Atomic/Nuclear Expansion
These events initiated the greatest era of expansion in U.S. atomic/nuclear history. Congress increased defense[spending] . . . as early as three weeks after the U.S.S.R.'s atomic explosion. Between late 1949 and 1952, the Nevada Test Site was established and began trials with atomic weapons. . . . In January 1950, Truman approved development of the hydrogen (fusion) bomb.
A Salvaging Operation
In 1952, U Reactor was [turned into] the Metal Recovery Plant. Its mission was to . . . recover uranium from the waste stored in Hanford's tank farms. . . . At the time, the scarcity of high-grade uranium supplies made this mission crucial. Much of the U.S. supply of uranium was housed in Hanford's [waste] tanks! Unfortunately, this mission also generated unexpectedly large amounts of chemically complex waste. Ferrocyanide [a mixture of iron and cyanide] was added to the waste [to remove the uranium.] The problems that have resulted from the ferrocyanide additions now constitute some of the most difficult ones in the Hanford Site cleanup program.
A "New Look" and Single Strike
Just as the first Korean War expansion was reaching completion, the election of President Dwight D. Eisenhower initiated yet another huge augmentation at [Hanford]. The new President, alarmed that the defense budget had tripled in the past three years, believed that a spending slowdown could be achieved by concentrating resources on atomic weapons rather than conventional forces. He called this policy the "New Look" in armaments. . . . [Eisenhower's] beliefs, combined with the threat perceived by the explosion of the first Soviet hydrogen bomb in 1953, and with the need for plutonium for the . . . American intercontinental ballistic missile development program, brought more rapid growth to Hanford.
The second Korean War expansion at the site, sometimes known as the Eisenhower expansion, saw the construction of KE and KW Reactors, the Plutonium-Uranium (PUREX) Plant, and 21 more single-shell waste tanks. The [start up] of the K Reactors in 1955 brought the total number of reactors operating [at] Hanford to eight. . . .
Peak Years of Production at the Hanford Site (1956-63)
The years 1956-63 witnessed the most intense defense production period at the Hanford Site. Cold War tensions, intensified by the coming to power of Nikita Khrushchev in the Soviet Union, drove the production of special nuclear materials. In 1955, Khrushchev emerged as victorious in the two-year power struggle that followed the death of Soviet dictator Josef Stalin. A confrontational Cold Warrior, Khrushchev told Americans in a 1959 visit: "Your grandchildren will live under communism!" He launched Sputnik I, the world's first man-made vehicle to orbit the earth, on October 4, 1957. Within seven months, he had launched Sputniks II and III. These achievements combined with a dazzling string of other Soviet "firsts" in space, including the launch of over 120 orbiting satellites by 1966, created a sense of national urgency in the United States. Clearly, this country would need nuclear power to energize instruments for its peaceful space exploration vehicles, and weapons material for its . . . missile systems. . . .
The United States elected President John F. Kennedy in 1960. Kennedy campaigned on the pledge that he would close the "missile gap" with the U.S.S.R., and "get America moving again." Policies that he initiated tripled the U.S. nuclear destructive capability by 1964. . . . In the Cuban "missile crisis" of October 1962, he successfully challenged the Soviet attempt to place intercontinental ballistic missiles in the western hemisphere. Hanford's weapons production, as it had done with President Dwight Eisenhower before him, gave Kennedy's words the backbone and the teeth to face down the determined U.S.S.R. . . .
Counting the Cost of a Safe Western Hemisphere
As the years of peak production went forward at the Hanford Site, volumes of wastes produced by the eight single-pass reactors [and other] facilities increased sharply. A 1956 "feasibility study" . . . resulted in the voluntary decision by Hanford managers not to construct additional . . . reactors at the site. However, power and fuel exposure levels at the existing reactors were raised many times during the years of intense production to the point where each of the eight older reactors operated at power levels nearly ten times those of World War II. Such levels brought thermal [heat] increases and added chemicals and [radioactive particles] to the Columbia River. The river was cooled by huge controlled spills of cold water from the bottom levels of Lake Roosevelt, behind Grand Coulee Dam, each summer from 1958 to 1964. . . .
Hanford and Atomic Energy Commission leaders discussed rising levels of contamination in fish tissues in the river and in shellfish in coastal waters near the river's mouth. Chemists and operators at the site sought new practices that would reduce [the amount of radioactive waste produced by Hanford's reactors]. Much time, effort and money were applied, but many research questions remained. During the same period, volumes of low-level wastes discharged to the ground also increased. . . .
Concerned, site scientists began monitoring [radioactive particles] in groundwater in 1961. Additional test wells were drilled in many areas of the site. In the mid-1950s, suspected and sometimes confirmed leaks from . . . high-level waste storage tanks began. . . .
On January 7, 1964, President Lyndon Johnson surprised the Hanford Site with his announcement of a decreased national need for nuclear materials. "Hanford To Cut Back in 1965," proclaimed the local newspaper the following day. Thus, peak production at the eastern Washington desert complex began to slow down.
Hanford Site Wastes in the Columbia River
The safety of the Columbia River from atomic wastes was among the earliest concerns expressed by the Manhattan Engineer District (MED) officials who built Hanford. . . . The economic value of the fishing industry, particularly the salmon catch, was affirmed by MED chief General Leslie Groves. Colonel Franklin T. Matthias, site commander, also noted the great love Northwest people had for the big river. The Columbia, the largest waterway flowing into the Pacific Ocean from the North American coast, is approximately 1,200 miles long. The Hanford Reach . . . stretches from about 300 to 350 miles upstream from the river's mouth and is a principal hatchery for salmon, steelhead trout, and . . . white fish.
. . . During 1946, several basic trends in the responses of fish to reactor [wastes] became evident. Young fish, possibly due to higher metabolic rates, accumulated more radioactivity in their tissues than did adults. . . .
Importantly, Hanford's early aquatic biologists noted that the most basic levels of the river's food chain-aquatic plants, algae, insects, crustacea, and smaller fish-concentrated radioactivity in their tissues at levels substantially higher than that of the water itself. Larger game fish, after consuming the river's biota, also possessed radioactivity levels higher than that of the water. By 1947, this trend had intensified to the point where the tissues of some fish in the Hanford Reach demonstrated concentration levels up to 170,000 times that of water in the Columbia. "This concentration factor," noted a site biologist, "is higher by a factor of several hundred than factors previously reported." Concerned, the aquatic researchers began a number of important . . . studies. In 1948, another site biologist summarized that the "concentrating ability" of the smallest and most basic organisms in the food chain was "in essence, the foundation of the radio-biological problem in the river
By this time, the results of numerous samples had shown that reproductive rates and general population balances among aquatic organisms in the Hanford Reach remained normal. Also, the Columbia River's water at the intake points for the Pasco and Kennewick domestic water supplies demonstrated radioactivity levels below permissible limits, and the slow sand and filtration beds used by city treatment plants allowed even more time for radioactive decay to take place.
The Challenge Met
Quantities of reactor [waste] released to the Columbia River, along with total [radioactivity], rose throughout most of the next 15 years [1948-63]. The construction of more reactors operating at increasing power levels caused these rises. During the same period, Hanford scientists contributed much effort, time and money to reducing the amount of [radioactive particles] entering the river. . . .
Over the years, policies were developed at Hanford that diverted the more concentrated [radioactive] wastes to holding tanks, thus adding protection to the Columbia. . . .
All of the eight single-pass reactors at the Hanford Site closed between 1964 and 1971. Quickly, levels [of radioactivity] in river water and organisms decreased, and by 1975, only a small measurable [amount] existed, mainly in . . . areas behind dams. In 1988, Congress passed a bill authorizing study of the Hanford Reach of the Columbia River for possible designation as a Wild and Scenic River. [As of early 1998, Congress is still debating whether to make the Hanford Reach a Wild and Scenic River.]
Meanwhile, along the shoreline and waters of the stunning Hanford Reach, sage grouse, American white pelicans, bald eagles, golden eagles, blue herons, salmon, steelhead, sturgeon, and many other unique animals make their homes, unconcerned with the people around them. [This is one of the greatest ironies of the Hanford Site: parts of the site constitute the most contaminated area in North America, while other parts of the site are remarkably free of radiation and serve as excellent wildlife habitat.]
History of 200 Area Cribs and Tanks
[Although levels of radiation in the Hanford Reach of the Columbia River are currently very low, the Hanford Site still poses considerable danger to the long-term health of the Columbia River. In December 1997 the Department of Energy acknowledged that radioactive wastes had been discovered in the groundwater below the leaky waste storage tanks in the "200 Area" of the Hanford Site. This contaminated groundwater is slowly moving toward the Columbia River.]
From the earliest operations at the Hanford Engineer Works (HEW), according to original chief health physicist Herbert Parker, liquid waste disposal to the soil . . . was "recognized as a temporary but necessary expedient . . . to avoid absurd costs on tank storage." The very first method of low-level liquid disposal was simply to pour wastes onto . . . the soil. However, this practice was abandoned in the spring of 1945, when the "swamp" areas receiving wastes demonstrated radiation readings higher than desirable. . . . That year the first Hanford cribs [tubs for holding radioactive waste] were constructed. . . .
[In the late 1940s, Hanford scientists discovered that the] sheer volume of liquid waste being disposed . . . had caused the groundwater to rise to unnatural levels and had altered the underground drainage patterns so that liquid wastes traveled laterally, toward the Columbia River, faster than had been anticipated. At the same time, [Hanford] scientists learned that plutonium was quite well held as soon as it entered local soils, but that other [radioactive elements] such as cesium-137 . . . traveled much faster to and through groundwater. . . .
Peak levels [of radioactive waste disposal] occurred in the mid-1960s, following a ten-year period in which nearly 64 billion gallons of low-level liquid wastes were discharged to 200 Area soils. . . .
Tank Space Quickly Becomes Scarce
Throughout Hanford Site history, high-level wastes have always been disposed to underground storage tanks, and tank space has always been limited. Sixty-four such single-shell tanks were built during World War II . . ., and by late 1946, half of these tanks were 100 percent full and the other half were 40 percent full. During the first huge postwar expansion (1947-49), 42 more single-shell tanks were built . . ., and 18 additional ones . . . were constructed during the 1950-52 expansion.
U Plant and REDOX Tank History
In 1952, the opening of both U Plant (the Metal Recovery Plant) and the Reduction Oxidation (REDOX) Plant introduced new complexities in tank wastes. U Plant's mission to recover uranium out of [Hanford's waste tanks] involved [an] extraction process that used . . . saturated kerosene [and highly toxic iron cyanide]. These processes created unexpectedly large volumes of
chemically complicated wastes. . . . Today, the presence of [iron cyanide] in 24 (known) tanks, and the ground discharges [from such tanks] constitute difficult cleanup challenges.
The initial operations of REDOX [reactor] brought the first self-boiling wastes to Hanford's tanks. [Some waste tanks'] contents began to boil in the summer of 1952, but the real problems arose the following winter, as cooling mechanisms . . . froze and broke. A "swamp" of contaminated [liquid] caused problems throughout the winter of 1952-53. The new SX Tank Farm, then under construction, was fitted with [special equipment] to accommodate self-boiling wastes. . . . During the large production expansions of the early 1950s at [Hanford], extremely tight space limitations drove decisions to allow ground disposal of some wastes originally designated for storage in single-shell tanks. The last four single-shell tanks at Hanford . . . were built in 1963-64. Since that time,  double-shell tanks have been constructed. . . .
No tank leaks were reported at Hanford before the early 1950s, although some pipes and fittings made from materials other than stainless steel did leak as early as 1945. The first significant, confirmed tank leak occurred . . . in 1956 (55,000 gallons). The largest known leak from a Hanford single-shell tank occurred in 1973, when 115,000 gallons escaped. Today, 66 single-shell tanks are listed as "assumed" leakers, but no double-shell tanks have leaked.
[Currently, the Department of Energy and private contractors are trying to devise a way to solidify and extract the highly radioactive liquids from the leaky tanks. The problem is so complex that the Department of Energy estimates that the removal of wastes from leaky tanks will not begin until 2002, at the earliest.]