Germans used chlorine gas to attack Allies in World War I. Gas from cylinders sank into ditches and low-lying regions because it was heavier than air. Chlorine gas reacts with respiratory moisture to generate hydrochloric acid, which damages lung tissue and suffocates. The gas could induce blindness by irritating the eyes, nose, and throat. Gas masks were developed after the Germans fired chlorine gas at the Second Battle of Ypres in 1915.

World War I Germans also employed phosgene gas. It was colorless, odorless, and more toxic than chlorine gas, inflicting severe respiratory damage. Phosgene, like chlorine gas, sank into trenches. It reacts with proteins in the lungs to create fluid buildup and lung tissue destruction, causing gradual asphyxia. Phosgene gas was first employed by the Germans in 1915 and became a major chemical weapon during the war. It was the deadliest wartime gas because its effects were delayed.

Germans employed very lethal sulfur mustard gas during World War I. It blistered flesh and produced severe chemical burns. It caused respiratory irritation and ocular blindness. Mustard gas's effects were long-lasting and debilitating, unlike chlorine and phosgene gas. It could induce lung damage and gradual asphyxia over several days. In 1917, the Germans introduced mustard gas, which caused widespread casualties and left many survivors permanently disabled.

Phenyldichloroarsine (PD) was a World War I German chemical weapon. Choking agents cause significant respiratory discomfort and damage. PD aerosols caused coughing, choking, and trouble breathing. PD caused long-term health issues and increased respiratory infection susceptibility, unlike previous chemical weapons. In the later phases of the war, the Germans deployed PD, which was less destructive than other chemical weapons but still caused large casualties and added to the war's devastation.

World War I German chemical weapons included diphenylchlorarsine (DA). It was a sneezing gas that irritated the eyes, nose, and throat, causing excessive sneezing. Inhaling DA aerosol caused instant irritation and pain. The Germans utilized non-lethal DA to interrupt enemy activities and create disorder on the battlefield. Soldiers exposed to DA recovered within hours. It added to the war's devastation and the soldiers' misery.

Austria-Hungary, a German ally, used chlorine gas against the Allies in World War I. Like the Germans, they released gas from canisters into opposing positions and lowlands. Inhaling chlorine gas caused respiratory injury, asphyxia, and death. It irritated the eyes, nose, and throat and could induce blindness. In 1915, Austria-Hungary first employed chlorine gas. Both sides developed and refined their chemical weapons technology during the war, and gas masks and other protective gear were developed to combat their use.

Austria-Hungary, a World War I ally of Germany, deployed phosgene gas against Allies. Phosgene gas, a colorless, odorless gas, caused significant respiratory damage. It reacts with proteins in the lungs to create fluid buildup and lung tissue destruction, causing gradual asphyxia. Phosgene gas from cylinders was heavier than air and sank into trenches and low-lying regions, making it hard to avoid. It was the deadliest wartime gas because its effects were delayed. In 1915, Austria-Hungary began using phosgene gas, which became a major chemical weapon.

The Ottoman Empire, allied with Germany and Austria-Hungary, deployed chlorine gas against Allied forces during World War I. In the 1915 Gallipoli campaign, chlorine gas killed many and frightened the enemy. Inhaling gas from cylinders in trenches and other low-lying regions caused serious respiratory harm. Gas-filled artillery shells were also used to boost the range and precision of Ottoman chemical strikes. Both sides developed and refined their chemical weapons technology during the war, and gas masks and other protective gear were developed to combat their use.

The Ottoman Empire, along with Germany and Austria-Hungary, deployed phosgene gas against Allied forces during World War I. In 1917, they utilized phosgene gas to frighten and kill opponents in the Sinai and Palestine Campaigns. Inhaling colorless, odorless phosgene gas caused respiratory system injury and gradual asphyxia. Gas from cylinders and artillery shells lingered in the air for hours, making it hard to avoid. To boost their effectiveness, the Ottomans tried mixing phosgene gas with mustard gas. Both sides developed and refined their chemical weapons technology during the war, and gas masks and other protective gear were developed to combat their use.

During World War I, the Ottoman Empire, allied with Germany and Austria-Hungary, deployed cyanide gas against Allied forces. Inhaling cyanide gas caused rapid respiratory failure and horrible death. In 1916's Caucasus Campaign, Ottoman artillery shells included cyanide gas, which killed many. Cyanide gas was superseded by less harmful chemical agents like phosgene and mustard gas, which were more successful at mass casualties. Both sides developed and refined their chemical weapons technology during the war, and gas masks and other protective gear were developed to combat their use.

France was one of the first nations to employ chlorine gas against Germany in World War I. The French Army fired 168 tons of chlorine gas from cylinders in 1915, creating a greenish-yellow fog that quickly drifted toward the German positions. Inhaling the gas damaged the lungs, causing asphyxia and death. French deaths were high, but the onslaught broke through German lines. France's deployment of chlorine gas inspired other nations to create chemical weapons, which were widely used during the war. Chemical weapons accelerated gas mask and other protective equipment development.

France was one of the first nations to employ phosgene gas against Germany in World War I. Phosgene gas caused respiratory injury and gradual asphyxia. At the Battle of Ypres in 1915, the French Army first used phosgene gas. Gas from artillery munitions killed many German soldiers. France's deployment of phosgene gas, which was more deadly than chlorine gas, changed the war's chemical weapon use. Phosgene gas and other chemical weapons boosted gas mask and other protective equipment development.

Both sides, including France, employed tear gas as a non-lethal weapon in World War I. Lachrymatory agent, or tear gas, produces extreme irritation to the eyes, nose, and throat, causing tears and coughing. Little amounts of gas disoriented and demoralized hostile forces. France initially employed tear gas in August 1914 at the Battle of Mulhouse. They utilized a "lacrymogene" to release tear gas on the Germans, temporarily blinding and weakening them. Tear gas was employed throughout the battle, but chlorine and phosgene gas were more potent.

British initially deployed chlorine gas against German forces in April 1915 during the Second Battle of Ypres. Inhaling the gas from cylinders caused serious respiratory damage, asphyxia, and death. The onslaught produced disarray in the German lines, but wind shifts transported gas back to British positions, killing many British soldiers. Britain's deployment of chlorine gas inspired other nations to create chemical weapons, which were widely used during the war. Chemical weapons accelerated gas mask and other protective equipment development.

World War I British chemical weapons included phosgene gas. The British initially employed phosgene gas in December 1915 at the Battle of Loos. Inhaling artillery shell gas caused respiratory injury and gradual asphyxia. The raid inflicted German losses, but wind shifts also killed British troops. Both sides utilized phosgene gas, one of the deadliest deadly weapons, throughout the battle. Phosgene gas and other chemical weapons boosted gas mask and other protective equipment development.

Britain first employed mustard gas in September 1917 at the Battle of Arras. Mustard gas burns and blisters skin, eyes, and lungs. The British swiftly constructed their own gas stocks after the German troops employed it. The gas from artillery munitions caused severe damage and death days after exposure. The Brits used mustard gas, which was more deadly than chlorine and phosgene gas, to change chemical warfare. Mustard gas and other chemical weapons propelled gas mask and protective equipment development.

World War I saw the US utilize chlorine gas. In September 1918, US troops employed the gas during the Meuse-Argonne Offensive. Inhaling the gas from cylinders caused serious respiratory damage, asphyxia, and death. The onslaught produced panic in the German lines, but wind shifts sent the gas back to US trenches, killing several American troops. When the US used chlorine gas, other countries developed chemical weapons, which were widely used during the conflict. Chemical weapons accelerated gas mask and other protective equipment development.

World War I US chemical weapons included phosgene gas. US forces first employed phosgene gas in October 1917 during the Meuse-Argonne assault. Inhaling artillery shell gas caused respiratory injury and gradual asphyxia. The onslaught confused the German lines, but wind shifts killed several American troops. Both sides utilized phosgene gas, one of the deadliest deadly weapons, throughout the battle. Phosgene gas and other chemical weapons boosted gas mask and other protective equipment development.

Lewisite, a World War I US chemical weapon, was never used. Blistering agents burned and blistered skin and lungs. American chemist Winford Lee Lewis created the weapon. Because of its toxicity and fear of reprisal, the US did not deploy Lewisite in warfare. However, the development of Lewisite and other chemical weapons during World War I showed the catastrophic impact of such weapons and led to international laws and agreements banning their use.

In October-November 1917, Italy employed chlorine gas as a chemical weapon in the Battle of Caporetto. Inhaling gas from cylinders caused respiratory injury and gradual asphyxia. Several Italian soldiers were gassed due to inadequate gas masks. The Austro-Hungarian army defeated the Italian army by using chlorine gas, which caused high losses and forced a retreat. The deployment of chemical weapons by both sides in World War I showed the catastrophic impact of such weapons and led to international regulations and agreements banning their use.

World War I Italy deployed phosgene gas as a chemical weapon. Inhaling artillery shell gas caused respiratory injury and gradual asphyxia. In October-November 1918, Italy defeated Austria-Hungary in the Battle of Vittorio Veneto, using phosgene gas. Austrian casualties from phosgene gas contributed to their downfall. World War I saw the development and use of phosgene gas and other chemical weapons, which led to international laws and treaties banning their use.

Russia deployed chlorine gas in World War I. At the Battle of Bolimov in 1915, Russian soldiers released chlorine gas from cylinders. The German forces were first confused and panicked by chlorine gas, but the wind changed direction and pushed the gas back into the Russian lines, prompting friendly fire and limiting its efficacy. Yet, World War I's deployment of chlorine gas and other chemical weapons showed their terrible effects and led to international laws and treaties banning their use.

During the 1916 Brusilov Offensive, Russia utilized phosgene gas as a chemical weapon. Inhaling artillery shell gas caused respiratory injury and gradual asphyxia. The Russian army's deployment of phosgene gas initially killed many Austro-Hungarian soldiers, but it was difficult to control and caused some friendly fire events. The deployment of phosgene gas and other chemical weapons during World War I showed the terrible effects of such weapons and led to international regulations and agreements banning their use.