One hundred years ago, Gen. John Pershing was leading the American Expeditionary Force in France, engaging an adversary whose arsenal included a significant chemical weapons component. Unlike the British, Canadian, and French forces, the US Army had never experienced chemical warfare and had, as a result, procured its chemical defense equipment and chemical munitions from its allies. Despite this support and ample training in France, American battalions integrated into the French and British lines in February 1918 suffered substantial casualties due to their inexperience in facing this new threat. Fortunately, the war would be over in November, and US casualties caused by chemical warfare agents were comparatively lighter than those of other nations.

Because of the concern that nations would be developing chemical weapons for future conflicts, the US military formed a “Chemical Warfare Service” within the Army in June 1918, which became the Chemical Corps in 1946. To this day, the Army Chemical Corps remains the only military branch that addresses the threat of weapons of mass destructions with dedicated, full-time specialists. While the US government signed the Chemical Weapons Convention in 1993, agreeing to renounce the use of chemical weapons, the US military has a continued focus on understanding the effects of chemical and biological warfare agents and developing defensive countermeasures against them.

Dugway’s Sheep Kill Incident

Dugway Proving Ground is an Army test and evaluation center located about ninety minutes’ drive from Salt Lake City, Utah. It was established in 1942 to test US chemical and biological weapons, given that the German and Japanese military were suspected of developing these weapons, and the US. government wanted a retaliatory capability. Because of its large and remote nature (eight hundred thousand acres, surrounded on three sides by mountains), it was also a site for conventional weapons testing and Ranger desert training. During the 1950s and 1960s, these tests included testing of artillery shells, aerial bombs, and aerial spray tanks designed to dispense chemical and biological warfare agents.

Fifty years ago this month, in 1968, this testing was interrupted by a significant off-post incident. State officials and veterinarians had been called to investigate reports of thousands of alleged dead sheep in Skull Valley, northeast of Dugway Proving Ground, on March 14. Many of those sheep were actually sick and unmoving, not dead but resisting medications. No other animal or human had been affected, but suspicion fell on the military center that its testing might have something to do with the illnesses. The general public began to hear news about the sheep deaths on March 19, causing the investigation to quickly escalate to the top levels of the Army and Utah state government. There had been three open-air nerve agent events on March 13, one of which was a test involving an F-4 fighter airplane operating two TMU-28B spray tanks, each holding 160 gallons of VX—a persistent nerve agent.

VX nerve agent is a liquid, not a gas, designed to fall to the ground and contaminate a particular area. The Dugway scientists had planned this test carefully, using chemical simulants having similar physical characteristics as the nerve agent in early trials so as to understand where the agent should drop. They had droplet cards dispersed not only on the target area but also miles downwind of the target, to account for the drift of lighter particles. The plane flew and dispersed its liquid contents about thirty miles from the mountain range separating the proving grounds from the ranchers’ herds. Following the test, the scientists were able to account for 98 percent of the agent dispersed. And yet, the governor of Utah, Calvin Rampton, was convinced that the Army was at fault and should compensate the ranchers for the loss of their sheep.

The scientists at Dugway were challenged by several factors. First they had no understanding of what VX nerve agent did to sheep, particularly if the sheep had eaten grass on which the agent had landed. They had worked with VX nerve agent for fifteen years, but never had a reason to test it on farm animals. Interestingly enough, no other animals or humans had shown signs of nerve agent poisoning. In attempts to replicate the incident, they exposed sheep to VX nerve agent and did not get the same symptoms of the disabled sheep in Skull Valley. Second, they were working at a military laboratory at the height of the Cold War. They weren’t supposed to talk about what they were doing or share data on VX nerve agent with civilians. Some in the public would view this silence as evidence of guilt.

Army Materiel Command headquarters in Washington, DC wanted to compensate the ranchers without admitting any fault in the matter and get Dugway’s scientists back to work. They weren’t interested in a long, drawn-out public debate as to the dangers of chemical warfare agents, given other priorities and inquiries from Congress as well as the Utah governor. No one was supportive of a long-term, comprehensive investigation.

An alternate theory, that local ranchers had used an illegal organo-phosphate chemical herbicide to spray fields that were only a few miles from the affected sheep, was not accepted. Certainly there were organo-phosphate pesticides such as Malathion and Parathion in use within the United States, and there was no Environmental Protection Agency to regulate their use. The Utah congressional delegation and the governor preferred to believe that five gallons of liquid VX nerve agent—the unaccounted-for amount—had traveled as a gaseous cloud 30–45 miles from the spray incident over a mountain range and affected only sheep in Skull Valley.

Thousands of the disabled sheep were still alive weeks after the spray trial. Many were shot by the ranchers and displayed to the Army investigators as “evidence.” At the end of the investigation, the Army would pay the ranchers for 4,372 sheep claimed to be killed by nerve agent, and 1,877 disabled and shot due to the ranchers being unable to sell their meat and wool. The Army paid $376,685 for the 6,249 sheep in the claims—about twice the market value at the time. Far from being over, though, the Army was drawn into a larger national debate over the US government’s role in developing chemical and biological weapons.

The military’s heavy use of Agent Orange and related herbicides in Southwest Asia was getting significant congressional attention in early 1969. That summer, the United Nations secretary general released a report discussing the growing proliferation of chemical and biological weapons, warning that there was no defense against them for any nation. A leak of chemical weapons on Okinawa sickened more than twenty US soldiers who were repainting ammunition bunkers that held them. All recovered, but the media attention grew. Congress passed a public law in November 1969 forbidding the open-air testing of any lethal chemical or biological warfare agent within the United States, unless the secretary of defense determined that such testing was necessary in the interests of national security, the US surgeon general reviewed the tests to ensure the public’s health and safety were protected, and the president informed Congress thirty days prior to the testing. As a result, all live-agent testing within the United States had to be limited to secure laboratories, and chemical weapons modernization essentially stopped.

The Impact of CB Weapons Testing Limitations

Politics and perception had essentially overwhelmed science and reason. This probably wasn’t the first time that this had happened, nor would it be the last. The point of this narrative, other than as a historical observation, is to reflect on what this has done to the preparedness of US military forces today. Yes, the United States no longer has a chemical weapons program. Yes, there is a Chemical Weapons Convention that nearly all nations of the world have signed, effectively eliminating chemical weapons as a future tool of warfare—we hope. North Korea is a particular exception to that treaty, and most assumptions are that, if North Korea goes to war against South Korea, it will use thousands of tons of chemical warfare agents against US forces. Are we confident that our forces have the necessary gear to protect themselves and sustain combat operations in such an environment? And do we have plans for how US military bases and ports will recover after being attacked with chemical weapons?

The answer is, it depends on the question. The US military has tested its chemical protective suits and detectors against different chemical warfare agents inside laboratories, and they should work just as well when exposed to the same chemicals in an outdoor environment. Standard military equipment, if contaminated with chemical agent, might remain a hazard for a long time, depending on the material upon which the agent was deposited and how persistent the chemical agent was. Much of it will probably be discarded rather than decontaminated. The larger question is what to do after the conflict if major defense systems, such as tanks, armored vehicles, fighter and strategic lift aircraft, and large ships become contaminated. Can we safely and confidently reuse formerly contaminated defense equipment?

The US military uses the Hazard Prediction and Assessment Capability (HPAC) to model the dispersion of chemical, biological, and radiological materials through the atmosphere. Using mathematical predictions of where the particles will go, based on points of impact, and knowing the exact hazard and weather and terrain information, one can estimate the deposition of the hazard and come up with casualty estimates. But it’s a prediction based on expected behaviors. Like all models, HPAC needs to be verified with actual test data which legally the Defense Department cannot obtain on its own. HPAC is very good software; however, all models need to be validated and verified if they are to be trusted.

These issues translate into areas of operational concern when military and political leaders ask, for example, what happens if a particular air base or port is hit with Scud missiles carrying VX warheads. What kind of casualties are we looking at? How quickly could we get a major base up and running again? Would we be able to bring multi-million dollar defense systems that were contaminated with nerve agent back to the United States for repair? These are tough questions without obvious answers, in part because of this legal constraint against seeking more data on the behaviors of chemical warfare agents.

This has an immediate impact on current and future operations. Because of the limited understanding of agent effects in a natural environment, there are different camps within the US military on what approach to take with regards to large-scale chemical weapons attacks on air bases and sea ports. One side claims that recent scientific data suggests agent persistency associated with VX nerve agent is relatively short-lived, especially if falling on asphalt and concrete, and therefore the issue can be handled without special equipment. Another side believes that persistent VX nerve agents will last days to weeks on equipment and buildings, that the old test data (pre-1970) was accurate. But we can’t confirm or refute that data without open-air testing.

This uncertainty has real-world consequences. Before Syria agreed to join the Chemical Weapons Convention and give up its declared chemical weapons, there was an option to consider directly attacking its numerous production and stockpile sites rather than letting them fall into the hands of nonstate actors. But the US military doesn’t know to what extent its weapons would destroy the chemical agent and how much chemical agent would be released beyond its containment. There are models that can estimate the impact of certain weapon systems and the agent released in different scenarios, but again, these are math models that are not verified by actual operational data.

A Way Forward

We may never know what really happened at Dugway Proving Ground fifty years ago. The point of this article is not to defend the former Dugway officials or to suggest that the US military should restart large-scale open-air chemical weapons tests at Dugway. Politically speaking, that would be unrealistic and self-defeating. But this event was fifty years ago! Our ability to conduct discrete chemical weapons tests and to monitor them with increasingly sensitive devices has improved dramatically in that timeframe. The nature of the threat has changed, from the Soviet Union’s preparations to use artillery and rockets to disseminate large amounts of chemical agent to terrorists using small-scale, single attacks with crude chemical hazards. We need to understand how these chemicals work in the real world so as to better develop countermeasures for US military forces as well as for emergency responders in our cities and states.

The case could be made that a national security emergency does in fact exist. In 1990, President George H.W. Bush signed an executive order identifying the proliferation of chemical and biological weapons as “an unusual and extraordinary threat” and declared a national emergency. This state of national emergency was modified and extended by Presidents Bill Clinton, George W. Bush, and Barack Obama. There is a defined threat to national security here that requires better understanding of the threat, if we are to develop better defensive countermeasures to protect US service members and citizens.

The testing does not have to involve the development and use of chemical-filled munitions in an outdoor environment. But at the least, being able to examine the reaction of grams of chemical agents poured onto asphalt, concrete, different soil compositions, and water in an outdoor environment would add realms of valuable data to necessary research. Being able to apply persistent nerve agent to the wing of an obsolete transport aircraft sitting in the desert would help engineer the next transport aircraft to resist said contamination. It doesn’t have to be done at Dugway (although Dugway should not be necessarily excluded from such testing). White Sands Missile Range could work, or the Nevada National Security Site might be feasible.

If a remote geographical area can be identified and proper instrumentation and safe procedures developed, then the US government could present Congress with the justification to resume open-air chemical weapons tests and get ahead of this threat. Chemical weapons arrived on the battlefield one hundred years ago and were deemed a significant national security threat fifty years ago. They still remain a significant threat to US military operations and homeland security. We can improve US response capabilities without endangering the American public, given modern technology and proper oversight. All we require is the fortitude to take on a politically charged and bureaucratic process and make the case.


Al Mauroni is the Director of the US Air Force Center for Unconventional Weapons Studies and author of the book Countering Weapons of Mass Destruction: Assessing the U.S. Government’s Policy.

The opinions, conclusions, and recommendations expressed or implied within are those of the author and do not necessarily reflect the views of the Air University, US Air Force, or Department of Defense.