National Security

Venting and Complaining

How the United States and the Soviet Union tried to conceal the problem of radioactive leaks from underground nuclear tests.

Fifty years ago today, the United States, the Soviet Union, and Britain signed the Limited Test Ban Treaty (LTBT) banning nuclear tests in the atmosphere, outer space, and underwater. While the three powers had tried to negotiate a comprehensive test ban treaty, they could not agree on verification procedures. Nevertheless, the international outcry against atmospheric nuclear testing and the radioactive fallout that it produced made the LTBT politically essential as well as a positive sign of easing superpower tensions not long after the Cuban Missile Crisis.

Underground nuclear testing remained permissible under the LTBT, but that posed a problem because the tests sometimes produced significant "venting" of radioactive gases and particles, which traveled across borders in violation of the treaty. Whatever the actual health risks may have been (probably far more serious for people living near the test sites than those far away), venting raised political problems because of the international concern about radioactivity. During the mid-1960s, venting incidents generated a raft of accusations back and forth between Moscow and Washington of possible LTBT violations, but the allegations eventually disappeared from the newspapers. A recently discovered archival document helps explain why: Both superpowers came to observe a tacit "gentleman's agreement against publicizing venting incidents" in order to depoliticize the issue and to avoid public criticisms of nuclear testing in general (although that was more important to Washington than to Moscow).

Some U.S. officials who participated in the test ban negotiations recognized that venting could be a problem, but before the LTBT was signed no U.S.-Soviet discussions took place on how to interpret language barring the release of "radioactive debris ... outside the territorial limits of the State" that conducted nuclear tests. Both sides developed divergent interpretations: Moscow interpreted the LTBT as prohibiting only releases of radioactive particles across borders, while Washington interpreted the ban more conservatively, to include particles and gases.

The first time that U.S. government agencies detected radioactive material from a Soviet underground test, diplomatic soundings occurred at the secretary of state level. A Soviet test on January 15, 1965, had produced debris that the U.S. Air Force collected in East Asia. After some debate among senior officials over whether the incident represented a treaty violation, Secretary of State Dean Rusk informed Soviet Ambassador Anatoly Dobrynin that Washington had detected the venting. He allowed for the possibility of error or accident noting that the incident could have resulted from a miscalculation of explosive yield or a misjudgment of the appropriate depth. Six days later, Dobrynin made a statement to Rusk essentially denying the possibility that any debris had crossed the Soviet border; therefore, the test did not affect the LTBT's "provisions."

Rusk said he would study the Soviet statement, but he maintained that "debris did clearly get outside the Soviet Union." The incident received considerable media play, including the Soviet denial, before Ambassador Llewellyn Thompson handed Dobrynin a note reiterating Rusk's point: Despite the Soviet rebuff, "scientific findings" demonstrated that debris had crossed the Soviet border. The State Department reminded the Soviets of their obligation to the terms of the LTBT and asked for more information about the test.

But Washington had its own venting problems as well. One early incident that worried the Atomic Energy Commission (AEC) was the PIN STRIPE weapons test in April 1966. A crack in the surface of the test site had led to the discharge of a cloud of radioactive gases that headed toward the Midwest. The Air Force Technical Applications Center (AFTAC), charged with monitoring overseas nuclear tests, tracked the cloud. While a herd of dairy cows in Nevada were temporarily put on "dry feed" (no grazing in the grass), a series of thyroid measurements led the AEC to find that the venting had created "no health risk." The Soviets learned about the incident and the military publication Red Star condemned it as a "tragic incident [that] has given rise to another wave of wrathful indignation in the world."

A major Soviet venting incident on October 27, 1966, involving a device with an explosive yield of about 1.2 megatons, was one of the last that received significant media coverage. Handled at the assistant secretary level by John Leddy, the exchanges with Ambassador Dobrynin did not produce any agreement. Dobrynin denied that there was a problem and the Soviets stuck to their story. In January 1967, when Assistant Secretary Foy Kohler brought up the October venting and yet another one on December 18, 1966, Dobrynin stated that his government wanted Washington to stop bringing up the incidents. It sought "to avoid future mutual inquiries" because they could be "exploited" to undermine the treaty.

By this point in the history of the venting controversy, the State Department was getting better at controlling information. It was not until October 1967 that the Washington Post got wind of the meeting the previous January, which it reported as a "secret protest" of Russia's December venting. Thereafter, newspaper coverage of U.S. government inquiries about venting incidents dried up, probably because nothing was leaking from the State Department or perhaps because the incidents were no longer news.

One venting that became a major news story, reaching the front pages of the U.S. press, was the Baneberry nuclear test on December 18, 1970. Everything went wrong geologically at the Nevada Test Site. The 10 kiloton test produced a "prompt, massive venting" of radioactive particles and gases, the worst such incident in the history of U.S. underground testing. The cloud reached 8,000 feet in height and radioactive particles were detected across the Canadian border. Owing to an error by the test controller, a warning was not issued quickly enough and radiation reached Camp 12 where hundreds of workers were stationed. The incident led to a six-month moratorium on underground testing accompanied by a significant effort to apply resources to containment procedures so that nothing like Baneberry happened again. Canadian diplomats cited the detection of radioactive particles but they did not make a formal protest, although relations with Canada were already strained because of U.S. underground testing at Amchitka, Alaska.

Dobrynin brought up the Baneberry venting but Assistant Secretary Martin Hillenbrand, in a tit-for-tat fashion, handed him a note about Soviet tests in December 1970 that had caused venting and the collection of radioactive debris outside of Soviet borders. As usual, Dobrynin denied that the December 1970 tests had released any radioactive debris. In the reporting cable, the State Department informed the U.S. Embassy in Moscow that it was following the "practice" of not publicizing "the nature of this exchange," but did not refer to a mutual understanding with the Soviets.

Moscow, of course, kept its media under tight control and thus did not face a major public opinion problem. Venting incidents continued; no major resources were expended to minimize them. Thus, the venting on September 27, 1971, became the subject of another exchange with Moscow. As had become the practice, Washington consulted with the British, the other original signatory of the LTBT, whenever it was about to lodge a protest. State Department official Holsey Handyside told British diplomat Christopher Makins that the United States did not bring up every venting incident with Moscow but that there had been six in the last year -- and the September 27 incident was the "worst" since October 1966.

In response to Makins's query about what the United States hoped to gain by protesting, Handyside explained that Washington wanted to build a "firm record" to respond to congressional inquiries, to encourage the Soviets to improve their containment practices -- not only to minimize atmospheric radioactivity but also to avoid encouraging opposition to "all nuclear testing." Moreover, Washington wanted to counter any Soviet "propaganda" charges about U.S. testing or its infrequent venting incidents. Summing up, Handyside explained that Washington "wished to remind the Soviets that the continuation of the existing gentlemen's agreement against publicizing venting incidents was to the advantage of both the US and the USSR."

Handyside was probably not referring to an explicit agreement, but to practices that both sides had been following for mutual convenience since the mid-1960s in response to the political problems raised by venting incidents.

The next day, Acting Assistant Secretary of State George Springsteen handed off an aide memoire  about the venting to Soviet diplomat Yuli Vorontsov. Replying on January 10, the Soviets stuck to their customary story that venting had not occurred and riposted by asking about a U.S. test that occurred on November 24, 1971. As Dobrynin had done in February 1967, diplomat Viktor Isakof asked the United States to stop bringing up the incidents. Whatever the nature of the agreement about venting, tacit or explicit, Isakof interpreted it as meaning to keep silent: "he thought an understanding had been reached not to keep making reference to small events." Not surprisingly, Soviet desk officer Jack Matlock responded that the September 27 venting "had not been a small event."

More Soviet ventings occurred during the 1970s and the United States continued to lodge protests. In some instances, Washington had evidence suggesting that Moscow had taken precautions to "reduce the amount escaping Soviet territory," but that it should have known that there was a "virtual certainty of at least gaseous radioactive material escaping Soviet territory." In its protest notes, the State Department noted that the U.S. government has made "rigorous precautions" which "have proved especially effective." The implication was that Moscow needed to take "effective measures" to reduce or prevent leakages of radioactivity. Nevertheless, the Soviets stuck to their story and denied that any radioactive material had crossed their borders.

The U.S. developed better procedures to minimize the venting problems, but some incidents occurred, although nothing like the Soviet ventings -- the local environmental impact of which was often severe. The record of quiet complaints about venting continued into the mid-1980s, with both countries following the "gentlemen's agreement." It was not until May 1986, the time of the Chernobyl accident, that Assistant Secretary of Defense Richard Perle, in congressional testimony, acknowledged the secret record of U.S. protests. He did not, however, mention any non-disclosure understandings. Determined to continue underground testing, no doubt the Reagan administration wanted to avoid speculation that Washington had collaborated with Moscow to prevent their disagreements from being fully aired.

National Security Archive/George Washington University

Dept Of Secrets

Israel's Secret Uranium Buy

How Argentina fueled Ben-Gurion's nuclear program.

In mid-July 1964, the State Department and the CIA sent a joint message asking the U.S. embassies in Argentina and Israel to check out an unverified intelligence report. They wanted to know whether the Argentines had agreed to sell Israel some 80-100 tons of uranium oxide, or "yellowcake," an essential product for fueling a nuclear reactor and thereby producing plutonium that can be used in weapons.

As it turned out, Washington had gotten information about the sale from the British government, which in turn had found out about it from the Canadians. All three governments were concerned about Israel's nuclear weapons ambitions, and the yellowcake transaction was strong evidence that something was amiss. American diplomats in Argentina confirmed the sale, which soon put the State Department in an awkward position: It would have to ask the Israelis about a transaction that flew in the face of their assurances that the country's nuclear program was for peaceful purposes only.

Israel's nuclear program presents a sort of paradox to historians. While it may be the world's worst-kept secret, it is also the world's most opaque nuclear program. One aspect of the Israeli nuclear program that has been especially mysterious is how and where Israel was able to obtain the raw material required to sustain a serious weapons effort. In the 1960s, this was a real challenge for U.S. intelligence, which was not entirely clear about the purposes of the Israeli program or whether Israel would comply with its "peaceful use only" pledge. It remains a challenge for historians today because Israel still does not acknowledge that it has nuclear weapons.

Previously obscure declassified archival documents on the yellowcake sale shed light on the global context of the Israeli nuclear program's early history. Edited and annotated by the two of us, 42 documents are being published today for the first time by the National Security Archive and the Nuclear Proliferation International History Project (in conjunction with the James Martin Center for Nonproliferation Studies). They demonstrate how vigorously Israel sought raw materials for its nuclear program and how persistently it tried to cultivate relations with nuclear suppliers. They also tell us how other players -- in particular the United States, Britain, and Canada -- viewed the program.

The story of the Argentine yellowcake sale to Israel has remained largely untold because Israel has gone to great lengths to keep it secret and because the U.S. government and its close allies have kept quiet about what they knew at the time. The United States has always been ambivalent about Israel's nuclear program, and exposing what it knew or suspected about the Israeli nuclear program could have caused the United States serious diplomatic problems with Israel's Arab neighbors and possibly the Soviet Union. This limited what Washington could do to circumscribe Israel's nuclear ambitions. Any kind of serious economic or political pressures, even if only contemplated by some, would have become public. And that could have been explosive domestically and internationally.

The U.S. government had been worried about an Israeli nuclear weapons program since late-1960, when the CIA learned and confirmed that, for nearly two years, Israel had been constructing a major nuclear facility (a reactor plus related infrastructure), with French assistance, near the town of Dimona in the Negev Desert. Initially, in support of Israel's desire to establish a nuclear program with military potential, the French apparently agreed to provide Israel with reactor fuel under loose safeguards. Under Charles De Gaulle, however, French policy changed, and it appears that by 1963, when the reactor was near completion, France imposed major constraints on supplying uranium to Dimona.

The Israelis had been trying to extract uranium from phosphate but that proved too costly; they needed a source that they could use freely, without external safeguards. South Africa was a prospective source. The French themselves recognized that Israel could try to acquire uranium from other countries, such as Argentina or Belgium, and in early 1964 they asked Washington whether the Israelis had "tapped" any such sources.

The Canadian government was interested in the Israeli nuclear program from its very inception. When Israeli Prime Minister David Ben-Gurion met Prime Minister John Diefenbaker on May 25, 1961, Dimona was at the center of the discussion. As he did with President John Kennedy a few days later, Ben-Gurion pledged that the Dimona project was peaceful. In March 1964, Canadian intelligence analyst Jacob Koop prepared a long secret report on Israel's nuclear program, asserting that Israel had all of the "prerequisites for commencing a modest nuclear weapons development project."

Not long after this report was prepared, Canadian intelligence learned (from a still-unknown source) that the Argentine government had made arrangements to supply 80-100 tons of yellowcake to Israel. By the end of April 1964, the British had seen the Canadian report. According to a British diplomat, "This means that Israel now has virtually unlimited supplies of uranium free of safeguards." Moreover, if the Israelis had reprocessing facilities, they could produce enough plutonium to "fuel a nuclear bomb" 18-20 months from the beginning of 1964.

The British soon shared the Canadian report with U.S. intelligence, overcoming Canadian reluctance to share it with its neighbors to the south (apparently the Canadians were irritated that the United States would not share the results of a recent American visit to Dimona). The CIA was initially skeptical, but in June 1964, the State Department and the CIA decided that the story should be checked out and sent the query -- reproduced below -- to its embassies in both Argentina and Israel. In September, the U.S. embassy in Buenos Aires confirmed from local sources that during 1963 Israel had arranged to purchase 80 tons of yellowcake from Argentina.

Evidently, the United States took seriously the information it obtained about the Argentine yellowcake sale. Like its British and Canadian allies, Washington was concerned that an Israeli bomb would threaten stability in the Middle East and complicate American efforts to curb nuclear proliferation worldwide. Moreover, to ensure that the Israelis were abiding by their public pledge that the Dimona facility was for "peaceful" use only, Kennedy and Prime Minister Levi Eshkol had secretly agreed in the summer of 1963 to allow American scientists to visit the reactor. The first U.S. team arrived in Dimona in early January 1964, but it is now known that the Israelis made "special arrangements" to prevent the visitors from seeing anything that revealed the true nature of the project.

In the fall of 1964, not long after the yellowcake sale was confirmed, U.S. diplomats brought the matter up with Argentine officials. While they did not object to the sale, they were concerned that there were no safeguards beyond a general agreement on peaceful purposes. The State Department wanted the International Atomic Energy Agency (IAEA) to be allowed to supervise future sales through reports and inspections. Admiral Oscar A. Quihillalt, the director of Argentina's atomic energy program, appeared sympathetic to U.S. concerns but said he could not do anything to address them. The sale to Israel could not be reversed or changed.

The U.S. embassy in Israel, including the CIA station, could learn nothing about the yellowcake from local sources, so the State Department asked Ambassador Walworth Barbour to go to a higher level. In June 1966, Barbour spoke directly with Foreign Minister Abba Eban. He was instructed to say that the yellowcake was "precisely [the] type of problem which augments apprehension" at "high levels" in Washington and elsewhere about nuclear proliferation. The problem also illustrated the "need for IAEA safeguards to reassure world of peaceful orientation [of] Israeli nuclear program." Barbour met Eban several times, but the latter was evasive -- apparently because he was not in the loop -- saying that he would confer with the deputy defense minister, Zvi Dinstein, who "keeps the store." If Eban ever provided Barbour with an answer, it has not surfaced in the archival record. Despite Israel's evasions, Washington apparently took no counteraction, but only continued to keep tabs through visits to the Dimona plant.

While the U.S. government was exploring the Argentine sale, it also investigated rumors during the spring of 1965 that the French uranium company in Gabon had asked Paris for permission to sell yellowcake to Israel. The French had already stopped such an effort in 1963, but when U.S. embassy officials in Gabon asked company officials about the rumored sales, no one would give any answers. As the French government controlled the exports, it was unclear whether the Gabonese or local company officials could actually divert uranium. Whether Israel received any yellowcake from Gabon during the 1960s still remains a mystery. In any event, sometime in mid-1968, Israel acquired 200 tons of yellowcake from Belgium in a complex clandestine operation known as the "Plumbat" affair, which involved a Mossad-run Italian front company and the at-sea transfer of uranium from a European cargo ship to an Israeli freighter.

The yellowcake issue was an important Israeli nuclear secret, but its biggest nuclear secret was the existence of a reprocessing facility to transform spent reactor fuel from Dimona into weapons-grade plutonium. For example, according to an October 1964 Special National Intelligence Estimate on nuclear proliferation, a "major deficiency, in terms of a weapons program, is the lack of a plutonium separation plant." The Israelis had told the Canadians and the Americans in 1961 that Dimona would include a pilot plant for reprocessing, but it was presumed that it would be too small to support a weapons program. In reality, however, the original French design for Dimona included a large underground reprocessing facility; this was Israel's most important nuclear secret, which Dimona technician Mordecai Vanunu later made public. Today, it is unclear exactly how much Western intelligence knew about the reprocessing facility and when and how it learned it.

The story of the yellowcake sale and the vain effort to prevent its military diversion is historical evidence of how difficult it was for the United States to stop Israel or any similarly determined government from undertaking a nuclear weapons program. That Israel was a major U.S. ally complicated matters. Tight secrecy about the Israeli nuclear program made it nearly impossible to raise pressure on Israel without risking an international incident.

From today's perspective, the story of the Argentine yellowcake highlights the continued lack of sufficiently tight international regulations for the trade of yellowcake. Despite U.S. support for tighter verification requirements during negotiation of the nuclear Nonproliferation Treaty in the 1960s, the agreements that the IAEA has with non-nuclear weapons states still do not require safeguards on the sale of yellowcake, only documentation of transfers. Changing this would be extremely difficult. That yellowcake remains politically charged was evident in the spurious allegations about Niger during the lead-up to the Iraq War. Secret controversies may still persist over who is selling yellowcake to whom and under what conditions, but we may never know.

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