Anthony L. Kovac, MD
Kasumi Arakawa Professor of Anesthesiology
University of Kansas Medical Center
Kansas City, Kansas

Chemical warfare gases, notably chlorine, phosgene, and mustard, were first used as weapons during the First World War. The initial large-scale use of chlorine gas occurred at Ypres, Belgium, on April 22,1915, when 150 tons were released by German troops from 6,000 cylinders, leaving approximately 3,000 Allied soldiers incapacitated and 800 dead. Thus, gas weapons had relatively low mortality, but high morbidity. Then, physical and psychological healing added weeks, even months to recovery. Extensive medical resources were required for treatment of these patients. As the war progressed these gasses were delivered by artillery shells.

The first two chemical agents were inhaled chlorine in gaseous form (Cl₂) and phosgene (CCl₂O), both causing lung injuries, with recovery - in the best of circumstances - measured in days. The third gas was sulfur mustard (C₄H₈Cl₂S), a vesicant or contact blistering agent which caused diffuse injury to skin, eyes, and even the respiratory tract if inhaled. Treatment and recovery times were most often measured in weeks to months.

Triage and care were initiated at first aid stations with subsequent transfer of gassed patients to casualty clearing stations, and then evacuation hospitals and base hospitals. At the National WW I Museum at Liberty Memorial in Kansas City, Missouri, medical records of numbers and types of gas-related injuries admitted to Base Hospital #28 (BH#28) have been preserved. From July 1918 through January 1919, this hospital treated 8,724 soldiers, including 930 with gas injuries. Treatment was supportive and included rehabilitative care. In BH #28’s diagnosis registry, the majority of gas injuries were simply listed as “gas” or “gassed.” Forty-nine entries included gas injury combined with one or more other types of injury, most commonly gunshot wounds or shell-shock. Sadly, many soldiers who suffered severe gas inhalation injuries died before being transferred to a base hospital, such as BH#28.

“Gassed” patients were identified by a “crayoned cross” on their foreheads. Triage of soldiers exposed to these chemical weapons was challenging because it was often difficult to determine if injury was acute, delayed, or just imagined by a frightened soldier. Initial diagnosis was difficult because often physical signs of exposure occurred late. Misdiagnosis occurred with “gas fright,” a psychological problem, as some solders believed they had been exposed to gas agents when they had not. Among the wounded and sick, gas cases were evacuated first. Rapid diagnosis and decontamination of soldiers and their uniforms was critical so treatment could commence without contaminating previously unexposed soldiers, particularly with sulfur mustard cases.

Twenty-two (2%) of 930 gas injuries were listed as “gas burns.” Treatment was removal of clothes, body washing, and continuous sodium hypochlorite skin soaking. Mustard gas contact caused a burn similar to 2nd or 3rd degree thermal burns. A long time was required for skin wounds to heal and to prevent chronic blistering.

Figure 1 - This injured soldier sat on ground contaminated by chemical nitrogen. The chemical passed through his clothing, causing irritation and inflammation of the skin followed by blisters. Eight days after exposure, the skin redness was replaced by a brown stain. The drawing was made 11 days after exposure. Skin healing was complete after 3 weeks. (From An Atlas of Gas Poisoning, American Red Cross 1918).

Fifty-five (6%) of 930 gassed patients were treated for eye injuries. These soldiers were photophobic for long periods of time. Treatment consisted of eye irrigation; acute conjunctivitis required immediate irrigation. Pupil contraction occurred from congestion and irritation, with severe cases requiring atropine ointment to artificially dilate pupils of patients who had eyelid spasm and pain. Several weeks of therapy were needed for adequate healing.

Figure 2 - Acute stage of a severely burned eye following exposure to mustard gas. Edematous eyelids with red, swollen conjunctiva. Corneal injury can occur. (From An Atlas of Gas Poisoning, American Red Cross 1918).

Two hundred sixteen (23%) of the 930 patients were treated for inhalation gas injuries. Inhaled mustard gas affected the entire lung and sloughing of the tracheal mucosa was common. Pharyngeal inflammation progressed to ulceration, causing difficulty breathing, often lasting for many days. Chlorine, phosgene, and a mixture of the two (called White Star after the white marks on artillery shells containing this gas) damaged lung tissue directly. Treatment was expectant and consisted of bed rest and oxygen.

Figure 3 - Trachea 12 days after mustard gas exposure. Inflammation at base of the tongue and pharynx. Trachea is red and glistening as the mucous membrane has been sloughed off. (From An Atlas of Gas Poisoning, American Red Cross 1918).

Two hundred-fifty (26%) of 930 gas-injured patients were treated for mustard gas exposure which often caused injury to lungs and skin lasting for long periods. This gas condensed to an oily liquid which could remain on skin, clothing, and soil for long periods. Mustard gas residues have reportedly remained active for decades and are capable of spreading by direct contact from contaminated ground to a person or even from person to person, often through contaminated clothing. Mustard occasionally caused delayed skin blistering, known to be particularly difficult to treat.

Mustard gas has low volatility and can cause injury at low concentrations. Mobile degassing units were used for decontamination (showers and areas for clothing removal and dressing changes). Water tank trucks were immediately available to give contaminated soldiers a two-minute shower.

Psychological effects of gas exposure included psychoneurosis or “gas fright”. Many soldiers initiated their own incorrect diagnosis of gas injury. Morbidity was high, but mortality low due to widespread panic, but with a resulting increased medical workload placed on available resources.

Gas injuries were difficult to treat because of delayed effects. Nine-hunded and thirty (9%) of patients admitted to Base Hospital #28 had gas-related injuries to the skin, eyes, and lungs, as well as psychological effects. Following gas exposure, recovery required weeks of hospitalization, incapacitating large numbers of soldiers for long periods of time. Gas injuries had high morbidity, low mortality and low long-term complications.

1. De Tarnowsky G. “Gas poisoning” in Medical War Manual No. 7, Military Surgery of the Zone of the Advance. Lea and Febiger, Philadelphia and New York. Pp 259-270.
2. Sidell FR, Takafuji ET, Franz DR. “Medical Aspects of Chemical and Biological Warfare.” Borden Institute: Walter Reed Army Medical Center Washington DC, 1997; pp: 90-102.
3. Base Hospital #28 Patient Registry, National World War One Museum and Archives, Kansas City, Missouri USA.
4. Medical Research Council (Great Britain). An Atlas of Gas Poisoning. American Red Cross, 1918.