At around 6 p.m. on April 22, 1915, a pale yellow cloud crept toward the Allied lines at Ypres, Belgium. Having first appeared from German positions several hundred feet away, the 4-mile-wide wall of vapor rode the evening breeze across no-man’s-land and descended over trenches occupied by a French and Algerian colonial division. In an instant, the unsuspecting troops began coughing and choking on noxious fumes. “Passive curiosity turned to active torment,” wrote a Canadian soldier who witnessed the carnage. “A burning sensation in the head, red-hot needles in the lungs, the throat seized as by a strangler.”
The first major poison gas attack of World War I had begun. When it was over, scores of Allied troops were dead, most of them suffocated by toxic fumes.
The use of “asphyxiating or deleterious gasses” had been officially banned during the Hague Convention of 1899, yet gas was later widely employed on both sides of World War I. In Germany, its most ardent advocate was Fritz Haber, a brilliant chemist and close friend of Albert Einstein. Haber personally orchestrated the April 1915 attack at Ypres, and he later worked to develop a host of other chemical agents for use in combat.
His actions saw him denounced as a war criminal, yet in the years prior to World War I, he had a very different reputation. Before he was branded Germany’s “Doctor Death” and the “Father of Chemical Warfare,” Haber was considered the mastermind behind one of the great life-saving discoveries of the 20th century.
Haber had a meteoric rise to the top of the scientific community.
Born in Breslau, Prussia, in 1868, Fritz Haber grew up in a Jewish family and later studied chemistry under Robert Bunsen, the man for whom the Bunsen burner is named. In 1894, he launched his academic career by securing a job as a professor at the Technical University of Karlsruhe in Germany. Over the next several years, the tenacious young scientist conducted a flurry of research and penned a celebrated textbook on electrochemistry.
His breakthrough came in 1909, when he solved one of the most pressing problems facing the industrialized world. At the time, scientists were warning that a scarcity of nitrogen fertilizers would soon lead to a global starvation epidemic. The agriculture of the day relied on manure, bat guano and other nitrogen-rich substances to enrich crops, but many predicted that the planet’s population was growing too fast for these methods to keep pace.
Haber’s answer to the crisis was revolutionary.
Through painstaking experimentation, he developed a method of using heat and high pressure to “fix” the nitrogen in the atmosphere by combining it with hydrogen to create ammonia—a natural fertilizer. When it was later industrialized by another chemist named Carl Bosch, this “Haber-Bosch process” allowed for ammonia to be synthesized in factories on a massive scale.
Haber’s discovery was a famine-preventing masterstroke—“bread from air!” was the common refrain at the time—but it also paved the way for a more controversial chapter of his scientific career. After the beginning of World War I, Germany looked to his research to feed both its citizenry and its munitions industry, which relied on nitrate for making explosives. Factories eventually sprang up across the country to churn out ammonia and fuel the march to war. According to many historians, Germany would have run out of weaponry in the span of a few years without the industrial nitrate production made possible by the Haber-Bosch process.
Haber immediately offered his services to the German military upon the outbreak of WWI.
Beginning in late 1914, he turned his scientific genius toward producing chemical weapons. His research saw him emerge as the chief proponent of using poisonous gasses to drive enemy soldiers from their trenches and break the deadlock on the Western Front. Many German military officers initially protested that gas was an ungentlemanly weapon, but Haber maintained that it was no more heinous than bullets or shells. He was even quoted as saying that “innumerable human lives would be saved” if chemical weapons could help end wars more quickly.
With the bald, cigar-chomping Haber in command, German “gas troops” eventually received orders to deploy chemical weapons at the Second Battle of Ypres. When the wind shifted in their favor on April 22, they opened nearly 6,000 pressurized canisters and unleashed 150 tons of chlorine gas on the Allied trenches. British and French officers denounced the attack as barbaric and cruel, but Haber considered it a potent display of the “psychological effect” that gas had on the enemy. Years later, a news reporter would note that the chemist still proudly displayed a framed photo of the Ypres gas cloud in his office.
Haber’s enthusiasm for chemical weapons was not universal in Germany.
His wife Clara Immerwahr, also a respected chemist, was reportedly disturbed by the horrific implications of his work. In May 1915, just a week after the first gas attack, she took her own life by shooting herself with Haber’s service revolver. Her suicide note has not survived, but many have since speculated that she was driven by guilt over her husband’s actions.
Despite his wife’s death, Haber immediately returned to duty and resumed his work with chemical weapons. For the rest of the war, he was at the forefront of Germany’s research on other poisonous agents such as phosgene and mustard gas. His chemical weapons program eventually included over 1,500 soldiers and scientists. Gas attacks would eventually kill some 90,000 soldiers during World War I, but in November 1918, Germany finally sued for peace.
Haber later found himself on the wrong side of the Nazis.
He fled to Switzerland after hearing that the Allies were seeking his arrest as a war criminal, but returned a few months later when the rumor proved unfounded. In November 1919, meanwhile, he was awarded the Nobel Prize in chemistry for his work in synthesizing ammonia. The news triggered a wave of dissent in Europe’s scientific community. A pair of French Nobel laureates rejected their prizes in protest, and another scholar lambasted Haber as “morally unfit for the honor and benefits of a Nobel Prize.”
Still a loyal German patriot, Haber continued to support his homeland after World War I and later embarked on an audacious quest to obtain gold from seawater—a process he hoped would help Germany pay off its crippling war debt. The scheme failed, however, and in 1933, Haber resigned from his research institute in protest of Hitler’s anti-Semitic regulations.
He would spend his final days roaming across Europe in search of work before dying of heart failure in 1934 at the age of 65. A few years later, the Nazis adapted a pesticide developed at Haber’s institute into Zyklon B—the notorious gas used in the concentration camps of the Holocaust. Among its many victims were members of Haber’s extended family.
In the years since his death, Fritz Haber has continued to occupy a controversial place in scientific history. According to biographer Daniel Charles, the chemist was both a hero and a villain, “a man who embodied the capacity of science to nourish life and destroy it.” Along with his tainted legacy as the “Father of Chemical Warfare,” he is also credited with saving millions from starvation by providing the world with a plentiful source of fertilizer. Today, it is estimated that his Haber-Bosch process continues to supply nitrogen for around half the world’s crops.