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Grim Prospect: Low-Yield Nuclear Weapons in the Middle East (Occasional Paper 2103)

As Secretary of State Blinken returns from his trip to Israel after its shooting match with Hamas, the question arises, just how peaceful is the Middle East ever likely to be. The immediate crisis and the shooting may be over in Israel but the long-term prospects for the region include the very grimmest of futures — nuclear proliferation and, with any bad luck, nuclear war.

Sound breathless? Maybe, but in the last 36 months, Iran’s, Turkey’s, and Saudi Arabia’s leaders have all threatened to get nuclear weapons and withdraw from the Nuclear Nonproliferation Treaty. One or more of them might actually follow through. After that, nuclear use in the region is hardly out of the question.

How bad might that be? I commissioned a graduate of MIT’s school of nuclear engineering, a contract analyst, Ms. Eva Lisowski, to find out. Using a variety of publicly available computer models, Ms. Lisowski assessed how much harm even a low-yield, nuclear weapon might do in the Middle East. She evaluated how many casualties these weapons would inflict against the populations in five major Middle Eastern cities — Tehran, Riyadh, Dubai, Cairo, and Tel Aviv (for the full report, click here).

What she discovered was disturbing: A one-kiloton device detonated at ground level would be at least as deadly as the 15 and 20 kiloton nuclear weapons used against Hiroshima and Nagasaki. The weapons dropped in 1945 were detonated at 1,600 feet to maximize their blast effects against buildings. One-kiloton ground-bursts, in contrast, maximize prompt radiation and fallout effects against people. The modeled casualty numbers, which ranged from scores to hundreds of thousands, were disturbingly high.

Ms. Lisowski's findings have major nuclear control implications. Her study was funded not only by private charitable foundations (Scaife, Carnegie Corporation of New York, and MacArthur), but by the U.S. State Department’s Bureau of Arms Control, Verification and Compliance. The question the bureau study asked was what might it take to verify and enforce the Nuclear Nonproliferation Treaty (NPT) over the next two decades.

This report suggests that, at a minimum, it will require more nuclear inspections. The International Atomic Energy Agency (IAEA) currently assumes that it takes 8 kilograms of plutonium and 25 kilograms of highly enriched uranium to make a nuclear weapon. These numbers (what the IAEA refers to as "significant quantities" or SQs) are a bit on the high side even for a 20-kiloton Nagasaki bomb. They are dangerously obsolete, however, and far too high for a one-kiloton device, which requires not 8, but only 1 to 3 kilograms of plutonium and not 25 kilograms of highly enriched uranium, but 2.5 to 8 kilograms.

This discovery would be academic were it not that the IAEA continues to use its SQ figures to determine how often it should inspect civil nuclear facilities and materials to prevent and deter them from being diverted for military purposes. If, as this study maintains, the agency’s SQs are three to eight times too high, then the agency’s recommended frequency of inspections (what it refers to as their “timeliness detection goals”) are also way too low.

None of this makes for pleasant reading. But ignoring or hiding these facts or, worse, lying about them will hardly help. Our government, as well as like-minded states and the IAEA, need to sort this out. 


On June 7, 2021, Eva Lisowki gave a presentation on this report.

To view her Powerpoint slides, click here.

To watch the video recording, see below. 




May 27, 2021
AUTHOR: Eva M. Lisowski
2103 Middle East Destruction (PDF) 3,818.52 KB

Grim Prospect: Low-Yield Nuclear Weapons in the Middle East

By Eva M. Lisowski



As noted in this paper’s preface, the idea for this study came from previous research Thomas Cochran and Matthew McKinzie completed for the Nature Resource Defense Council. That work focused on a single American case and was not widely disseminated. This volume of research was financially supported by grants from the MacArthur Foundation, the Scaife Foundation, the Carnegie Corporation of New York, and the US Department of State’s Bureau of Arms Control Verification and Compliance. Brooke Buskirk formatted and helped with the volume’s editing. Finally, the paper would not have been possible without the extensive research work of the paper’s author, Eva Lisowski.


Dark Future: Small Nuclear Weapons, Grotesque Effects

This study is part of a two-year project funded by the United States Department of State’s Bureau of Arms Control, Verification and Compliance; The Scaife Foundation; the MacArthur Foundation; and the Carnegie Corporation of New York to determine what verifying and enforcing the Nuclear Nonproliferation Treaty (NPT) requires. It was prompted by recent public announcements by political leaders in Iran, Turkey, and Saudi Arabia that their nations might acquire nuclear weapons.1  Such public statements are unprecedented and suggest nuclear weapons might not only spread in the Middle East, but might actually be used.

To get an idea of what modifications would be useful, NPEC sought the advice of Dr. Thomas B. Cochran, former director of the Nuclear Program at the Natural Resource Defense Council (NRDC). Dr. Cochran said that his NRDC colleague, Matthew G. McKinzie, using a government model no longer publicly available, found that a 1-kiloton (kt) nuclear device, if detonated at ground level in an area with a high population density, e.g., near the Brooklyn Bridge in New York, would produce causalities comparable to those inflicted in the nuclear bombings of Hiroshima and Nagasaki. Dr. Cochran also noted he and his NRDC colleague, Christopher E. Paine in earlier work had shown that a 1-kt nuclear device could be readily made with far less fissile material than the IAEA considers “significant,” and, as a consequence, the IAEA’s safeguard standards were woefully inadequate.

To validate these findings, NPEC commissioned Eva Lisowski of MIT to see what the numbers might be using publicly available models. Her case focused on what would occur if a relatively crude, small nuclear 1-kt bomb was set off in several major Middle Eastern cities. The device was detonated at ground level to maximize radiation casualties rather than at ~1,600 feet, as the Nagasaki bomb was to maximize blast damage to buildings. Using the best available models, Ms.Lisowski determined that a 1-kt device could cause just as many, if not more, casualties than the 20-kt bomb detonated over Nagasaki at ~1,600 feet.

This is worrisome. It suggests the United States and like-minded nations should recalibrate how much diverted nuclear material international inspectors should be trying to detect. This report’s findings are also relevant, if not actually timed, to the renegotiation of the 2015 Iran nuclear deal. This agreement adopted what the IAEA believes are the amounts of plutonium and highly enriched uranium needed to make a nuclear device. Set back in 1977,2 these “significant quantities” — eight kilograms of plutonium and 25 kilograms of highly enriched uranium — are enough to make a first-generation implosion weapon with a yield not of one kiloton, but of 10 to 20 kilotons — i.e., the range of explosive energy the Hiroshima and Nagasaki bombs unleashed.

These figures, however, are not just old, they are dangerously obsolete. The reason why is simple. Set the significant quantity high and the frequency of inspections needed to reliably detect a diversion of that quantity declines. Set the number low and the inspection frequency needed increases.

Critics of the IAEA safeguards system (myself included) have long argued that the IAEA’s significant quantities are at least twice as large as what they should be to build a 10-20 kt device. In fact, other than South Africa, states that planned to get or actually acquired nuclear weapons historically used much more modern and efficient designs than those employed in 1945. By tying its significant quantities to outdated, inefficient 1945 weapons designs, then, the IAEA has kept the frequency of its inspections (what it calls its “timeliness detection goals”) far below what would otherwise be called for to detect smaller quantities of plutonium and uranium sufficient to build more modern and more likely (e.g., hollow core and levitated pit) designs.

This is an important point. It is not one, however, that this commissioned study focuses on. Instead, for purposes of this study, Ms. Lisowski was directed to use a first-generation, 1945 implosion design. But rather than build a 20-kt device and set it off at ~1,600 feet, as the United States did in Nagasaki, this study uses a 1-kt device set off at ground level — a contingency weapons states actually plan for.3 Ms. Lisowski’s conclusion: A 1-kt device at ground level can easily be as lethal as the 20-kt Nagasaki weapon that was set off at ~1,600 feet.

What difference should this make? Even if a 1-kt device used a crude, 1945 implosion design, it would only need three kilograms of plutonium or eight kilograms of highly enriched uranium. Yet, the IAEA has designed its timeliness detection goals to detect not three, but eight kilograms of plutonium and not eight, but 25 kilograms of highly enriched uranium. If one uses only slightly more modern designs than the IAEA uses (i.e., ones perfected in the late 1940s), the amount of plutonium needed to make a 1-kt device drops to 1.5 kilograms and the amount of highly enriched uranium down to four. These lower figures range between less than one-half to less than one-fifth of the IAEA’s current significant quantities and suggest just how much the IAEA should lower their own figures.

This may seem to be radical. It is not. Late in 2016, Olli Heinonen, the former deputy director-general of the IAEA for safeguards, argued that the agency should lower its significant quantity for plutonium from eight kilograms down to between two to four kilograms.4 This study makes similar recommendations. At a minimum, if the United States and other like-minded nations are eager to avoid the prospect of destructive strikes equivalent to Nagasaki and Hiroshima, they will want to recalibrate international inspections to account for much lower significant quantities.

Henry D. Sokolski
May 2021


1. See Norah O’Donnell, “Saudi Arabia’s Heir to the Throne Talks to 60 Minutes,” CBS NEWS, March 19, 2019, available at ; Reuters Staff, “Erdogan says it’s unacceptable that Turkey can’t have nuclear weapons,” Reuters, September 2019, available at ; and Al Jazeera Staff, “Iran to quit NPT if its nuclear programme referred to UN: Zarif,” Al Jazeera, January 2020, available at

2. See Marvin Miller, “Are IAEA Safeguards on Plutonium Bulk-Handling Facilities Effective?” (Washington DC, August 1990), available at

3. On this point, see Samuel Glasstone and Philip J. Dolan, Eds., The Effects of Nuclear Weapons (Washington, DC: U.S. Departments of Defense and Energy, 1977), available at

4. See Ollie Heinonen, “North Korea’s 5th Nuclear Test — What Now?” FDD Policy Brief, September 17, 2016, Available at


To view the full occasional paper click here.


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founded in 1994 to promote a better understanding of strategic weapons proliferation issues. NPEC educates policymakers, journalists,
and university professors about proliferation threats and possible new policies and measures to meet them.
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