Could U.S. water supplies be contaminated with radiation in a terrorist attack?

By Andy Shen, Natan Hekmatjah, Seth Freeman and Peter Katona

With the country focused on the implacable advance of the coronavirus and the latest distractions of severely divisive politics, are we dropping our guard regarding very real continuing threats to our national security?

Water terrorism is as old as war itself. The necessity of water for survival as well as its vulnerability to contamination have been recognized over the millennia of human history. The fact that most known attempts at water contamination as a combat strategy have not been successful combined with the reality that pulling off an effective contamination attack is extremely difficult have encouraged many experts to discount the water supply contamination threat. However, others who have studied the problem are equally convinced that an attack on some part of the U.S. water supply is inevitable, that it is only a matter of time.

A successful water contamination attack could deliver a devastating one-two punch. The immediate effects — people sickened and dying — could be catastrophic, but, in addition, subsequent events could prove even more destructive. A population living with undrinkable water is faced with a drought emergency. A human being can live for at most a hundred hours or so without drinking, less in warm weather or when active. Water scarcity and thirst have often been the precursors to civil unrest and armed conflict. The present ruinous multi-sided war in Syria, for example, grew out of the effects of a searing drought in that region.

It is true that an effective contamination attack would be difficult to execute because it would require a challenging multi-step process: producing or obtaining large amounts of a toxic agent and then finding a way to release it into a water supply in sufficient quantities to spread and, if biological, survive long enough to reach the target population. On the other hand, prior to September 11, 2001, few would have thought a coordinated hijacking of four airliners and their use to destroy both World Trade Center towers and inflict devastating damage on the Pentagon was a very likely occurrence. Given the potential for massive destruction in a water supply attack, we can be sure that clever adversaries with the motive to cause widespread harm are intensely working on ways to make one effective.

Moreover, the goal of a terrorist attack is not to prevail by killing adversaries but by scaring them. Thus, a high number of casualties is not necessary for a terrorist attack to be successful. The terrorist wins by sowing fear, panic, confusion, discord and distrust — any or all of which could be accomplished with an effective water supply contamination attack.

Serious contamination of a water supply could be accomplished with basically three types of materials — biological pathogens, chemical toxins and radiation. Is a significant attack with the last of these, radiation, a realistic possibility?

Radioactive isotopes (radioisotopes) are already present in much of the world’s drinking water supplies. Some radioisotopes occur naturally, while others come from nuclear or radioactive activity near a water source. Consumption of or exposure to these substances in large or sometimes even small amounts can be harmful or life-threatening. Certain radioisotopes, such as Caesium-137, Iodine-131, and Strontium-90, are both highly volatile and water-soluble, making their potential impact even more dangerous. Would it be possible to contaminate a water supply, large or small, using chemical radiation?

Water-based terrorism already happens around the world. In fact, recent years have been marked by a sharp increase in water-based terrorism incidents, skyrocketing by 263% from 1970–2016 and increasing by 68% after September 11, 2001, through 2016. South Asia (particularly India and Pakistan) has been hit hard, experiencing the largest number of water-based terrorism incidents. Perpetrators include ISIL and the Taliban. In South America, guerilla groups such as Colombia’s FARC and Peru’s Shining Path have attempted water terrorism, and in Africa, the terrorist group Al-Shabaab deliberately restricted water access to certain cities in an attempt to overthrow the Somalian government during the Somalian Civil War.

Europe and the United States have not been spared. In 2000, French workers who were denied benefits for their jobs dumped gallons of sulfuric acid into a tributary in an attempt to poison the surrounding wildlife and population. In the U.S., in 1970, terrorists blackmailed a military officer into supplying them with information and chemicals, which they intended to use to destroy the local water supply. More recently, in 2002, an Al-Qaeda cell ordered a member to contaminate water supplies in Seattle as a practice run in order to study the dams and river tributaries in the area for the purpose of planning a future attack. None of these attacks, however, used radiation to contaminate the water.

Different forms of radiation are always present in most water. Aside from naturally occurring radionuclides such as Potassium-40 from cosmic rays, many water sources also contain trace amounts of radiation from nuclear weapons testing, medical facilities, and other industries that produce radioactive waste with long half-lives. In general, the likelihood of experiencing adverse effects from drinking radiation contaminated water is low, but the National Research Council (NRC) identifies three possible groups of physical effects and risks from consuming radioactively contaminated water: developmental, genetic, and somatic. Possessing an excess of radioisotopes in one’s body could potentially have very serious consequences in one or more of these three categories.

A radiation attack on water could be harmful, but is it even possible? As a thought experiment we examined the possibility of contaminating a specific target, Lake Mead. Lake Mead serves drinking water to millions of people and irrigation water to vast areas of farmland in the western United States, including California, Arizona, and Nevada. Many parts of this water system are easily accessible and vulnerable to a terrorist attack, which if successful on even a limited section of the system could result in widespread panic and severe economic loss.

It is possible to calculate the amount of Cesium in various forms which would be required to contaminate a body of water the size of Lake Mead. We considered the amount of the Cs-137 needed to contaminate Lake Mead at just below half of full capacity and found that it would require 37.80g or 51.08g depending on the type (EPA MCL or WHO GL) of Cs-137. In powdered form that equates to roughly 3–4 tablespoons of granulated sugar, which doesn’t seem like a great deal, but the material is only sold legally in very tiny amounts, so that much Cs-137 would be quite difficult to obtain through legitimate means.

The result of our calculations, therefore, is that contamination of a large body of water such as Lake Mead is technically feasible but unlikely because of the difficulties of obtaining sufficient radioactive material to have an impact. However, contaminating a city’s water tower supply could be possible if it is readily accessible, and contaminating a limited water supply, such as a small well or water tank that supplies water for a few households, would require even fewer resources and could definitely be achievable. If the active agent were, for example, Cs-137, with a half-life of 30.17 years, contamination could produce permanent, long-lasting damage and increase the risk of cancer in those exposed to the water.

Some of the radioactive materials most likely to be used in such an attack are legally available for purchase. Others can be, and have been, stolen from medical equipment and shipments to and from science labs. It can be obtained.

Thus, while we agree that the probability of a large scale water terrorism event using radiation remains low, we believe the threat should be taken seriously and stronger precautions than currently exist should be put in place. There are nearly 160,000 drinking water supply systems in the U.S., yet there is no single office and no one person reporting to the Secretary of Homeland Security with exclusive responsibility and authority for the protection of this vast and vital complex. A coordinated water safety effort could more securely protect the nation’s drinking water. Some actions which would significantly enhance the safety of U.S. water supplies include:

1) a protocol for reporting suspicious behavior and threats;

2) designing alterations for limiting access to facilities and their computers and other technology;

3) posting security guards at all facility entrances and points of vulnerability;

4) securing all facility access points with meter boxes and locks and reconfiguring vulnerable sections for greater security;

5) maintaining vigorous surveillance of the airspace above and the terrain around water supply areas with video, sound, and other electronic monitoring;

6) conducting background security checks on all facility employees;

7) investigating all structures within fifteen miles of a water storage site;

8) bolstering capability for the gathering of pre-attack intelligence;

9) having a plan, in the event of attack, for clear and transparent messaging from highest levels of government to deal with the fears and concerns of the public regarding radiation contamination of the water supply.

One thing is absolutely certain: it would be far worse to underestimate the threat, do nothing and be wrong than to overstate the threat, prepare for it and be wrong.

* * *

Peter Katona, MD, is Clinical Professor of Medicine at the UCLA David Geffen School of Medicine and Adjunct Professor of Public Health at the UCLA Fielding School of Public Health. He chairs the UCLA Covid-19 Infection Control Working Group.

Andy Shen is a fourth-year undergraduate statistics student at the University of California, Los Angeles.

Natan Hekmatjah, BS, is a Summa Cum Laude Psychobiology graduate from UCLA.

Seth Freeman, MPH, is an Emmy-winning writer/producer for television, a playwright and a journalist, who writes about technology, policy and public health.

Seth Freeman, MPH, is a journalist, a playwright, and an Emmy-winning writer/producer of television, who created the series Lincoln Heights.

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