Understand the development of chemical weapons during World War I and its hazardous impact


NARRATOR: Armies have been attacking each other with gases as far back as ancient Greece. But the chemicals available way back then were much less effective than, say, pouring boiling oil on someone. All that changed, however, with the development of deadly new gases during World War I.

Before World War I, all the major European powers signed a pact promising not to put poison gas in projectiles and fire them at each other. But as the supposedly short war dragged on, both sides started experimenting with poison gases. Bromine was an early example.

Like other halogens, bromine has seven electrons in its outer energy level. But it desperately wants eight. So in theory, bromine would shred cells in the eyes and nose to steal electrons, like a super-powered tear gas. It sounds like a powerful weapon. But in reality, most of these bromine gas attacks failed. When the Germans attacked the Russians, for instance, the freezing Russian winter meant the gas couldn't even vaporize in the air. And however irritating, bromine rarely incapacitated soldiers. Troops didn't even realize they'd been attacked in most cases.

That changed when a bald, mustachioed German chemist named Fritz Haber entered the scene. Haber is best remembered for figuring out how to convert nitrogen in the air to ammonia, a precursor for fertilizer. Billions of people around the world today depend on that chemical reaction for food. And he won a Nobel Prize for it. But Haber was willing to pervert this chemical genius to help Germany win the war. And he set out to craft deadlier chemical weapons, leading a group of scientists the German military ghoulishly called "the disinfection unit."

He decided to ditch bromine and focus on chlorine. Chlorine sits above bromine on the periodic table and is more aggressive about attacking cells for electrons. If bromine is a soldier on horseback, chlorine is an armored tank. Chlorine was so powerful, in fact, that Haber believed it would break the trench warfare stalemate across Europe and win the war immediately. Haber actually directed the first chlorine attack in person at Ypres, in modern Belgium.

It began on April 22, 1915, as soon as the winds shifted in Germany's favor. Specially trained troops crept forward in the trenches and turned the valves on more than 5,700 canisters of chlorine gas. A green cloud 50 feet high and 4 miles long rolled towards the French lines. When chlorine hits the mouth and throat, it induces a reflex to hold your breath. Eventually, you gasp, and the chlorine reacts with the water inside cells to make acids. The acids tear open the capillaries and air sacs in your lungs, spilling out fluids that collect in pools and prevent the lungs from inhaling oxygen.

Victims of chlorine attacks actually drown on dry land. Although estimates vary, several thousand men probably succumbed that day in Ypres. And what did Germany gain from the first successful gas attack in history? Nothing. German generals didn't think the attack would work, so they didn't have enough troops ready to occupy the enemy's trenches. They gained very little ground.

Chemists on both sides invented several other chlorine-based gases, including the truly nasty phosgene and mustard gas. But strategically, gas attacks accomplished little. Both sides began to manufacture gas masks by the thousands. In a pinch, soldiers could also urinate on their handkerchiefs and hold them over their noses for protection. Millions of men did suffer lung damage and millions more lived in terror of gas attacks. But all that suffering still couldn't break the trench stalemate.

Gas warfare also destroyed Fritz Haber's personal life. His wife, Clara, shot herself, in part, because of his work on gas. And although Haber won the Nobel Prize in 1918, he was also condemned as a war criminal by the larger scientific community. Even worse, his beloved homeland betrayed him. When the Nazis took power in Germany in the 1930s, they persecuted Jews like Haber. He died in exile in 1934.

Gases continued to haunt Haber's legacy. Early in his career, some under his watch were working with an insecticide called Zyklon. Just before World War II, a German company tinkered with the formula to produce a second generation of the gas. This became known as Zyklon B. And concentration camps used it to gas millions of Jewish prisoners, including Haber's relatives.

In the century since World War I, gas attacks have lost none of their power to terrify us. Why? Because they creep in silently on the wind. Because they turn the very air we breathe into a weapon. In fact, gas has always been a far more effective psychological weapon than a physical one. Gases have killed far fewer people in history than bullets, but they retain a horror unmatched by almost any other weapon.