World War I brought major changes to warfare, especially with the introduction of tanks and more advanced weapons. One of the most deadly new weapons was poison gas, which spread across battlefields and caused agonizing deaths. During the Battle of Osowiec Fortress, German forces launched a devastating gas attack on Russian soldiers, an event later remembered as the “Attack of the Dead Men.”
Chemical warfare during World War I
Chemical warfare made its debut on the battlefield during the onset of the Second Battle of Ypres during the First World War. The engagement was fought for control of a crucial strategic area, and the Germans were determined to secure victory, even if it meant resorting to the use of a perilous and somewhat uncontrollable weapon.
At around 5:00 PM on April 22, 1915, German soldiers unleashed canisters containing a deadly mixture of poison gases, bromine and chlorine. The noxious fumes drifted across the battlefield toward the Allied line, compelling two colonial French divisions to abandon their positions in a desperate attempt to escape the lethal vapor. With no specialized equipment to counter the attack, troops were forced to fashion makeshift respirators from linen.
As a result of this battle, the British withdrew to a new defensive line. Soon after, poison gas became a familiar presence on the Western Front, despite being deemed a war crime under both the 1899 Hague Declaration Concerning Asphyxiating Gases and the 1907 Hague Convention on Land Warfare. Both sides resorted to its use and continued to refine the types of gases deployed, with the British using gas for the first time during the Battle of Loos in September 1915.
Among the most notorious gases used during the war was mustard gas, which made its battlefield debut in July 1917. While not as immediately lethal as chlorine, mustard gas had the sinister quality of being heavier than the surrounding air, allowing it to linger and cause harm long after its initial deployment, persisting in the soil for weeks. Its effects were savage, inflicting severe injuries upon the unlucky soldiers who came into contact with it, with the pain being described as unbearable.
Osoweic Fortress
In August 1915, Osowiec Fortress, situated in what is now northeast Poland and originally constructed by the Russian Empire a century before, became the focal point of fierce battles. Strategically positioned amid marshland, the fortress acted as a vital barrier against Germany’s expansionist goals, marking it as a prime target.
During World War I, the Germans launched multiple attacks on the fortress, enduring sustained artillery fire in response. Even the Russians recognized the structure’s resilience under such intense bombardment.
To penetrate its defenses, German forces crossed two trench lines before reaching the imposing walls and battlements, where Russian sharpshooters awaited them. This complex defensive setup enabled the Russian garrison to hold the position with only a small force.
The first major attack occurred in September 1914, when 40 infantry battalions from the German 8th Army, supported by heavy artillery, failed to take the fortress. Another barrage followed that winter, but the fortress withstood it. Despite these setbacks, the Germans were not ready to abandon their efforts quite yet…
Launching the Battle of Osoweic Fortress
Kaiser Wilhelm II was determined to force Russia out of the war and set his sights on destroying Osoweic Fortress. In August 1915, he committed significant resources to the attack. While artillery played a role, the plan mainly depended on Field Marshal Paul von Hindenburg, who was accompanied by 14 infantry battalions, a sapper battalion, 30 artillery batteries, and 24 to 30 heavy siege guns.
The Russians had only about 900 defenders, while the Germans had an estimated 7,000 troops, making the situation seem hopeless. However, Osoweic Fortress had proven its strength in the past, giving the defenders hope that it could hold out once again. This time, though, they faced a terrifying new weapon—one designed to cause massive destruction.
Deploying chlorine gas on the battlefield
Paul von Hindenburg’s plan involved more than conventional weapons. He had thirty cylinders of chlorine gas prepared to drive the defenders from the fortress, but he was forced to wait for favorable conditions. At last, in the early hours of August 6, 1915, the wind turned in his direction. At 4:00 AM, the gas assault was unleashed.
The destructive power of the attack became apparent even before the chlorine cloud reached Osowiec Fortress. Observers reported seeing a yellow-green haze moving steadily toward the Russian lines, leaving discolored grass in its wake. The damage it caused to vegetation offered a grim indication of what it would do to human lungs.
The Russians were particularly vulnerable because they lacked any effective defense against chemical warfare. As the toxic fumes spread across the battlefield, soldiers desperately attempted to shield themselves by holding water- or urine-soaked undershirts over their mouths and noses.
Attack of the Dead Men
What happens when chlorine gas is inhaled? It combines with the body’s moisture to produce hydrochloric acid. Essentially, the Russians were being consumed from within by the very air they breathed. With such a deadly weapon, it seemed their fate was sealed. Many perished due to Paul von Hindenburg’s ruthless tactic, but they were far from defeated, as the Germans were about to discover.
Lt. Vladimir Kotlinsky was unwavering in his mission to drive back the enemy. He and 60 other men suffered horribly, wrapped in blood-soaked bandages and coughing up bits of their lungs as the acid ravaged their bodies. Yet, they still charged at the Germans as they breached the fortress.
It became a slaughter—but for the Germans. From the perspective of the Kaiser’s elite, they were facing what seemed like an army of the undead. The sight was so horrifying that they retreated in terror. Some were so overwhelmed with fear that they ran straight into barbed wire.
What happened to Osoweic Fortress after the Attack of the Dead Men?
Osoweic Fortress fell following the Attack of the Dead Men, but not by German hands. The Russians later took it apart themselves that month, when they realized the situation was hopeless. The soldiers that day managed to cheat death, if only briefly, to repel the enemy and maintain their might for as long as humanly possible.
While he’d led a fierce resistance against the Germans, Vladimir Karpovich perished later that evening. Prior to his death, he’d transferred control of Osoweic Fortress to the 2nd Osovetska Sap Company and Władysław Strzemiński, who himself had been severely injured in the attack.