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In 1903 a young priest working on his doctoral degree at the Catholic University of America in Washington, D.C., was studying the reaction of the gas acetylene and arsenic trichloride in the presence of aluminum chloride. When these compounds were mixed, the flask turned black, and after the mixture was poured into water, a black, gummy mass formed that had a penetrating odor and caused the priest to become seriously ill. He was hospitalized for several days while recovering from the toxic effects of the compound and decided to postpone indefinitely any further investigations of it. However, the priest, Father Julius Arthur Nieuwland, described the reaction in his 1904 dissertation. The toxic substance later became known as lewisite, one of the most deadly poison gases developed until well after World War I. Produced by the United States during the latter part of that war, it had also been independently discovered, although not manufactured, in Germany. During World War II, the United States, Great Britain, Germany, the Soviet Union, and Japan produced lewisite. Since that time other countries have manufactured the compound, including Iraq, North Korea, and perhaps Libya.

In the early evening of April 22, 1915, the first lethal poison gas attack of World War I occurred at Ypres, Belgium. German troops discharged approximately 160 tons of chlorine gas that slowly crept toward the Allied trenches with the aid of a gentle wind. French and Algerian soldiers first noticed two strange yellow clouds approaching, and soon men began to choke, cough, suffocate, and retreat in horror. Smoke and fumes made their panic worse because they could not see around them. Some soldiers buried their faces in the dirt, hoping to protect themselves from the unknown killer. A few officers who were educated in chemistry realized the value of urinating on a cloth and breathing through it to crystallize and neutralize the chlorine, and they instructed others to do so.

The unprecedented attack killed more than 5,000 men and injured 15,000 others. There were between 880,000 and 1,297,000 gas casualties during World War I, and gas warfare may have caused more than 26,000 deaths. American casualties from poison gas totaled almost 72,000, and of these more than 1,200 died. The Central Powers and then the Allies attacked with the weapon even though two separate prewar international conferences had banned the use of weapons and projectiles intended to diffuse asphyxiating, deleterious, or poisonous gases.

The United States did not declare war on Germany until April 2, 1917, but by then it had already begun research into chemical gases. The Bureau of Mines first conducted chemical warfare research early in 1917, under the direction of Van H. Manning. Founded in 1910 to investigate poisonous and asphyxiating gases in mines, the bureau offered its services to the Military Committee of the National Research Council (NRC) on February 8, 1917. On April 3, the committee formed the Subcommittee on Noxious Gases, composed of army and navy officers and members of the Chemical Committee of the NRC, and Manning was appointed as its chairman. George A. Burrell, who worked for the Bureau of Mines, became the director of research on war gases on April 7 and immediately began working on a suitable gas mask for American soldiers.

The need for more chemists quickly arose, and in May the Bureau of Mines was authorized to accept help from laboratories at twenty-one universities, three companies, and three government agencies. Furthermore, in July 1917 a central laboratory was established at American University in Washington, D.C. The weapons development and testing facility would become known as the American University Experimental Station. The War Department began suggesting in September 1917 that the labs at American be militarized, and ten months later, in June 1918, President Woodrow Wilson agreed, transferring the extensive work at the university to a newly formed army subdivision, the Chemical Warfare Service. Eventually, more than 10 percent of all the chemists in the United States became directly involved with chemical warfare research during World War I.

One of them was Winford Lee Lewis, who left Northwestern University in 1918, where he was an associate professor of chemistry, to become the director of the Offensive Branch of the newly formed Chemical Warfare Service unit at Catholic University. This unit, called Organic Unit No. 3, was given the task of developing and producing novel gases, especially compounds containing arsenic. In April 1918, following the suggestion of the Rev. John Griffin, who had been Julius Nieuwland’s chemistry adviser at Catholic, Lewis reviewed the priest’s dissertation and read about his experiments with arsenic trichloride. He further investigated and perfected its reaction with acetylene, with aluminum trichloride acting as a catalyst.

Lewis wrote that the resulting compound ‘…took on a nauseating odor and [caused] marked irritation effect to the mucous surfaces. The headache resulting persists several hours and the material seems to be quite toxic.’ The perfected product was named after him, christened lewisite. The government eventually ordered Lewis to stop working on the compound at Catholic University, under the pretext that it was ineffective. They did this, however, in order to trick German spies into believing that Lewis’ work had not been productive. In truth, other researchers continued evaluating and perfecting lewisite at nearby American University.

Lewis believed in gas warfare and defended its use throughout his life, saying that it would make wars more humane because it would shorten them and innocent civilians would suffer less. He also believed that ‘Providence’ would intervene and give the most advanced people the best gas. Lewis furthermore characterized the horrors of gas warfare as exaggerations and insisted that chemical battles are the most efficient and economical of all fights.

Nieuwland, who became a renowned professor of chemistry at the University of Notre Dame, held similar beliefs. When questioned in 1936 about his discovery of lewisite, he asserted that poison gas rendered warfare more humane:

By the introduction of gas and other modern instruments of warfare, a progressively small percentage of combatants have been killed. In biblical times, thousands of men met in the middle of a plain and slashed one another until only a few were left standing. Today, the primary aim is not to kill but to incapacitate. And poison gas is an ideal method of achieving that aim. If a man goes to a hospital suffering from gas, he is as useless as if he were dead and to care for him, several other persons must be kept out of the battle lines. The chances are that ultimately the victim will recover.

Lewisite, the chemical formula of which is C2H2AsCl3, was given the code names ‘Methyl’ and ‘G-34’ during World War I. Perhaps its most enduring pseudonym is ‘Dew of Death.’ General Amos Fries, commander of the American Expeditionary Forces’ Gas Service and later director of the Chemical Warfare Service, so named it because there were plans to spray lewisite over the enemy from airplanes, and the gas was thought to be so deadly that ten planes armed with it could eliminate every trace of life in Berlin.

After the war, many newspaper articles sensationalized lewisite, attaching properties to it that the poison gas did not have. The Cleveland Plain Dealer on June 15, 1919, reported that lewisite was seventy-two times more powerful than mustard gas, considered the king of war gases at that time, and that a single drop on the back of a hand was fatal. Also, on February 26, 1923, the San Francisco Journal stated that lewisite would sterilize the ground so that ‘nothing will grow upon it for at least two years and perhaps longer’ and that one drop of it on living flesh caused ‘mortification.’

Lewisite is primarily a vesicant (causing blisters). It secondarily irritates the lungs and is a systemic poison. Upon contact with the skin, it causes large, painful, fluid-filled blisters, especially on the extremities, back, and scrotum. It also acts as a toxic lung irritant by causing swelling, inflammation, and destruction of the lining of the airways. The lining may subsequently slough off and form an obstruction in the airway, making it difficult to breathe. It is a systemic poison because absorption of arsenic through the skin causes pulmonary swelling, diarrhea, restlessness, weakness, below-normal temperature, and low blood pressure. A victim feels its effects immediately.

Lewisite can be delivered as a vapor, an aerosol, or a liquid and is believed to be most damaging in low-temperature, low-humidity, and dry nonalkaline conditions. It can be fatal in as little as ten minutes when inhaled in high concentrations. Lewisite is also persistent, lasting up to six to eight hours in sunny weather and even longer in cold, dry climates. The poison vapor is about seven times heavier than air and will therefore hover along the ground and enter caves, trenches, and sewers.

Mustard gas, like lewisite, is a vesicant. The two chemicals have many of the same characteristics, but there are also important distinctions. Mustard agents can be composed of sulfur- or nitrogen-based compounds, whereas lewisite is composed of arsenic. Sulfur mustard was the compound used extensively during World War I, first by the Germans and later by the Allies. Similar to lewisite, it is effective as a liquid, vapor, or aerosol, but in contrast to lewisite, its effects are delayed for up to a few hours. They will both form large blisters on the skin, but mustard lesions take about two to three times as long to heal. Whereas lewisite has a lower freezing temperature than mustard agents, both compounds can persist for days, even months under certain conditions. Mustard gas accounted for almost 40 percent of the total gas casualties in World War I.

After lewisite’s transfer to the American University Experimental Station, Captain James Bryant Conant was ordered to find a method to manufacture it in large quantities. Formerly an instructor of chemistry at Harvard University, Conant directed the Organic Research Unit No. 1 of the Offense Research Section at American.

The lewisite work at the Experimental Station was dangerous. A huge tub of soapsuds had to be readily available for soldiers to plunge into if gas from leaking pipes or vats of boiling chemicals contaminated them. Soldier-chemists tested human volunteers and animals to determine the effectiveness of the compound. George Temple, the head of the station’s motor maintenance department, repeatedly volunteered to be burned by poisonous gases. When a sample of lewisite was placed on his forearm, it caused redness, swelling, and huge silver-colored blisters that took eight weeks to heal.

One morning in August 1918 an explosion caused by a faulty timer on a bomb sent lewisite gas across a field and toward the homes of residents near the American University campus, including that of former senator Nathan B. Scott. Scott, his wife, and his sister-in-law were gassed while sitting on their porch. Not long after the accident, the lewisite work at the university ceased and the Chemical Warfare Service ordered production moved to a secret plant twenty miles east of Cleveland, in Willoughby, Ohio.

The Willoughby plant was located on the site of the former Ben-Hur Motor Company. Soldiers first arrived at the site at the end of July 1918 and found that, although the office building was mostly completed, the plant floor had never been graded. A plumbing system had been installed, but there were no working sewer or water lines in the facility. The pipes had frozen over the previous winter, so the system had to be removed and totally redone. The electrical wiring was only partially complete and had been installed haphazardly, so it had to be removed and reinstalled.

Finding contractors to remodel the plant was difficult. Most of the nearest ones were located in Cleveland, and transportation, food, and housing for construction workers had to be arranged. Further, the workmen wanted to be reimbursed for the cost and time of traveling. Fortunately, Willoughby contractors were eventually found and hired, but only after appealing to the town’s mayor. The workers took from July 28 to mid-August to remodel the factory. Security was tight. A barbed-wire fence was erected around the facility, and guards maintained a twenty-four-hour watch. Klaxon horns and an alarm system were also installed to warn of the presence of intruders. Eventually the site included four barracks to house the twenty-two officers and 542 soldiers working at the facility, a mess hall, and a forty-eight-bed hospital (neither of the two deaths that occurred at the plant was from the effects of lewisite).

The soldiers working there initially were not allowed to leave the grounds except for meals, and all their mail went through a post office box, No. 426, in Cleveland, without any mention of Willoughby. On August 10, Maj. Gen. William L. Sibert, director of the Chemical Warfare Service, visited the Willoughby plant and told the soldiers that as long as they maintained secrecy about the plant, the army would allow them to enter the town of Willoughby, but they were still not permitted to go to Cleveland due to the fear of espionage.

Each of the soldiers at the facility was issued a gas mask that had to be kept nearby or worn in the alert position at all times. Many of the men worked to the point of complete exhaustion, trying to make the plant operational as soon as possible because the government had ordered three thousand tons of lewisite to be ready for a planned spring 1919 offensive against the Germans.

In September 1918, the War Department realized that, in order to satisfy all its planned uses for lewisite, production had to be doubled. That entailed a large expansion at Willoughby. New equipment was ordered, and the plant layout changed to make room for it. Amazingly, by November, just five months after construction started, the plant had begun full production of ten tons of lewisite per day.

On November 11, however, the war suddenly ended. Early in December, the men began dismantling, inventorying, and disposing of the plant’s equipment and materials. By March 1919, all of the plant’s soldiers were gone.

From the time the soldiers had arrived in Willoughby until the day they left, the town’s government, Red Cross, and residents were all extremely helpful and friendly. They often hosted receptions and gatherings for the soldiers, provided pies for their Thanksgiving dinner, and even donated a grand piano to the boys. When townspeople asked the soldiers what they were doing at the Willoughby plant, the soldiers responded that they were working on a formula for rubber, which explained the strong odors that the plant emitted.

According to Nate A. Simpson, one of the soldiers assigned to the plant, the army did not reassign a single soldier from the top-secret facility until the war was over. The plant became known as the ‘mousetrap’ because once you were there, you knew you were not going to leave until the war was over.

There are different stories pertaining to what happened to the gas produced at Willoughby after the armistice was signed. Some say the plant never produced chemicals, but in 1957 workmen dug up several laboratory bottles containing lewisite on the grounds of the old facility. Others suggested that the army hauled between a few tons and 150 tons of lewisite to the Atlantic Ocean by train in big steel casks that were under guard. There the material was carefully transferred onto barges and dumped at sea. Another account suggests that 150 tons of lewisite was en route to Europe when the war ended, and the ship transporting it was subsequently sunk rather than be allowed to return the deadly chemical to the United States.

Two British scientists, Stanley Green and Thomas Price, published the formula for lewisite in The Journal of the Chemical Society in 1921. According to General Fries in his book Chemical Warfare, the formula’s publication was unfortunate because the highly secret compound became known throughout the world, perhaps allowing Japan and Germany to learn about it and develop manufacturing techniques.

Until 1943 lewisite was thought to be equal to or better than mustard gas. However, U.S. Army tests done during World War II on lewisite found that unless the human subjects were defenseless or unconscious, they immediately felt the pain of exposure and would leave the area and protect themselves. Because mustard does not cause immediate effects, soldiers were more likely to be exposed for longer periods. Army testers also found that it was very difficult to get effective concentrations of lewisite vapor. Furthermore, the development of British anti-lewisite, which can prevent burns caused by lewisite and reverse its systemic effects, was believed to reduce the combat effectiveness of the chemical weapon. For those reasons, the U.S. military has not considered lewisite an effective chemical agent since World War II.

Other countries apparently did not agree with this evaluation. For example, the Soviet Union produced huge quantities of the material, disposing of approximately twenty thousand tons of it in the Arctic Sea during the late 1940s and ’50s. More recently, a plant specifically designed to incinerate lewisite and mustard gas has become operational at Gorny, Russia.

Although chemical weapons were not used in major combat during World War II, the Japanese used lewisite and mustard gas in China during most of the war years. In one horrible experiment, prisoners were forced to drink ‘crude water,’ which was a liquid form of lewisite or mustard gas. In addition, more than thirty-five hundred Chinese died in October 1941 at Ichange in the Yangtze Valley after a suspected lewisite attack. Lewisite artillery shells were found on New Guinea, indicating that the Japanese had planned to use the agent against Allied forces. Germany also conducted lewisite experiments on concentration camp inmates.

From 1940 to ’43, the United States produced lewisite at a small pilot plant at Edgewood Arsenal and then later at Huntsville, Pine Bluff, and Rocky Mountain arsenals. About twenty thousand tons of the agent had been produced before the plants were shut down. Along with disposing of the enemy stockpiles, the United States also dumped most of its own lewisite into the Atlantic and Pacific oceans after the war. One of the 1948 dumping operations was referred to as Operation Geranium because lewisite has a geraniumlike odor.

More recently, Iraq allegedly used lewisite and a mustard gas-lewisite mixture against Iran in the 1980s. The deadly chemical was detected in three separate 1991 instances during the Persian Gulf War, and at least one Iraqi prisoner of war claimed in February 1991 that Iraq had lewisite-filled munitions in its inventory.

A 1999 article in Environmental Health Perspectives reported that lewisite is still produced in very limited quantities in the United States (presumably just for military preparations) and the country’s remaining stockpile is stored at Desert Chemical Depot in Utah. And recently in Washington, D.C., lewisite and mustard agents, hastily buried and forgotten when the American University Experimental Station closed down, have been discovered in the ground, requiring a hazardous waste cleanup operation by the army’s Corps of Engineers.

Lewisite, the major American contribution to chemical weapons development during World War I, has had an amazing history, from its inadvertent discovery by a priest in 1903 to its presence a hundred years later in the arsenals of some countries. Most notably, North Korea has an estimated twenty-five hundred to five thousand tons stockpiled. Whether lewisite will eventually be used in combat situations or as a terrorist weapon — and, if so, how effective it would be — remains to be determined.


This article was written by Joel A. Vilensky and Pandy R. Sinish and originally published in the Spring 2005 edition of MHQ. Joel A. Vilensky and Pandy R. Sinish are the authors of Dew of Death: The Story of Lewisite, America’s World War I Weapon of Mass Destruction. For more great articles, subscribe to MHQ: The Quarterly Journal of Military History today!