Barnegat Light, New Jersey

Brandon Seidler

Barnegat Light, New Jersey, 2015; photograph by Brandon Seidler, who treated the image with chemicals similar to the fertilizer runoff polluting the area

What is often called “the first use of weapons of mass destruction” took place on April 22, 1915, near the town of Ypres, in western Belgium. Six months earlier, Germany’s hopes for a quick victory in World War I had been dashed on the banks of the Marne, and the country had enlisted some of its top scientists to break the stalemate. One of them, Fritz Haber, the director of the Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry, had suggested releasing chlorine gas. Since the gas is heavier than air, Haber reasoned, it would sink when released; this would allow it to infiltrate the trenches of the French and English forces.

The Germans had signed the Hague Convention of 1899, which forbade the “use of projectiles the sole object of which is the diffusion of asphyxiating or deleterious gases.” Nevertheless, by interpreting this clause literally—the chlorine would be released not from projectiles but from canisters—the country’s military commanders managed to convince themselves that the move was permissible. In any event the French, they complained—accurately—had already been releasing “deleterious gas” in the form of grenades filled with ethyl bromoacetate, a skin irritant that can be fatal. Just a few months after Haber proposed his idea, he personally supervised the placement of nearly six thousand canisters of chlorine along the front. Ten canisters were attached to a single spout, to minimize the number of men needed to release their contents.

Haber, a Jew who had converted to Christianity, was self-critical, ambitious, and restlessly brilliant. His work ranged from the electrolysis of solid salts to the thermodynamics of gas reactions. A few years before the start of World War I, he devised a method for converting ordinary nitrogen into ammonia. The Haber-Bosch process, as it became known, allowed for the production of synthetic fertilizers and fundamentally changed the world: without chemical fertilizers, it is estimated, some 3.5 billion people—almost half the globe’s population—wouldn’t be alive today.

During the war the Germans, cut off from supplies of saltpeter, which is both a fertilizer and an ingredient in gunpowder, used the Haber-Bosch process to generate a substitute. This enabled them to continue to produce explosives and, according to Haber himself, prolonged the war for three years.

The canisters Haber had had installed near Ypres were supposed to be opened on April 22 at 4:00 AM. But there was no wind that morning, so the attack was delayed. Finally, in the afternoon, a breeze came up, and at around 5:00 PM the Germans turned the valves. The chlorine—some 300,000 pounds of it—drifted across the landscape in a billowing cloud. Within a few minutes it had reached the French lines. A Canadian soldier who was stationed to the north of the French recalled seeing a “queer greenish-yellow fog that seemed strangely out of place in the bright atmosphere of that clear April day.” A German soldier who had helped to release the gas and then witnessed the results reported:

When we got to the French lines, the trenches were empty. But in a half mile, the bodies of the French soldiers were everywhere…. You could see where men had clawed at their faces, and throats, trying to get their breath. Some had shot themselves. The horses, still in the stables, cows, chickens, everything, all were dead.

The Germans were unable to press the advantage Haber had given them, because frontline commanders hadn’t put much faith in the plans of a civilian and so hadn’t prepared to push through the opening the gas attack created. “I was a college professor, and therefore not to be heeded,” Haber later complained. But, once again, using chemistry, he had altered the course of history. The attack at Ypres initiated a ghastly cycle, as each side sought—and deployed—ever more potent chemical weapons. After chlorine came phosgene, hydrogen cyanide, diphenylarsine chloride, cyanogen chloride, and bis(2-chloroethyl) sulfide, otherwise known as mustard gas. In 1919 Haber was awarded a Nobel Prize for his work on ammonia synthesis. Not surprisingly, given what he’d done in the interim, the award is one of the most controversial in Nobel history.

The story of Fritz Haber’s work to feed humanity on the one hand and gas it on the other lies at the center of Frank A. von Hippel’s The Chemical Age. For von Hippel, a professor of ecotoxicology at Northern Arizona University, the story turns out to be an unusually personal one. Von Hippel’s great-grandfather was James Franck, a German physicist who won his own Nobel Prize, in 1925, for his research on electrons. During World War I, Franck was assigned to Haber’s institute in Berlin. Among his duties was testing the efficacy of gas masks and filters. (Other scientists on the testing crew included Otto Hahn, who received a Nobel Prize in chemistry in 1944, and Hans Geiger, who later invented the Geiger counter.) The testing was performed by sealing crew members into a room, filling it with poison gas, and having them stay there until they felt their masks starting to fail. Needless to say, the work was extremely dangerous. Had things gone ever so slightly differently, von Hippel might never have been born.


Von Hippel is interested in the ways people have solved problems with chemicals and, in the process, created new problems. He introduces his book with the example of Thomas Midgely Jr., who, in 1921, discovered that he could eliminate “knocking”—essentially tiny explosions—in car engines by lacing gasoline with tetraethyl lead. Over the next fifty years, some six trillion gallons of leaded gasoline were produced and combusted. Lead is toxic—in the course of his research, Midgely himself suffered lead poisoning—and the price of eliminating knocking turned out to be neurological damage in kids all over the world. (Studies suggest that this damage persists into adulthood.) But Midgely was just getting going.

Early refrigerators relied on noxious chemicals, like methyl chloride and sulfur dioxide. After several people were killed by appliances leaking methyl chloride, Midgely went searching for a replacement that would be nontoxic and also chemically inert. In 1928 he and his team came up with the world’s first chlorofluorocarbon, or CFC. For marketing purposes, the compound was dubbed Freon.

Freon was a giant step forward for Frigidaire, but a great step back for planet earth. Released into the air, the compound made its way to the stratosphere, where it damaged the ozone layer, which protects the globe from ultraviolet radiation. The first scientist to appreciate the impact of CFCs on the stratosphere was F. Sherwood Rowland, a chemistry professor at the University of California Irvine. One night Rowland came home from his lab and told his wife, “The work is going very well, but it looks like the end of the world.” (For his insight, Rowland, too, received a Nobel Prize, in 1995.) By the time Rowland’s calculations were confirmed, in the mid-1980s, a large “hole” had opened up in the ozone layer over Antarctica. The environmental historian J.R. McNeill has observed that Midgley “had more impact on the atmosphere than any other single organism in earth history.”

Von Hippel spends the first several chapters of The Chemical Age tracing the discoveries that allowed scientists in the nineteenth and twentieth centuries to identify and then fight the pathogens that cause diseases like plague, yellow fever, and malaria. For reasons that are unclear, these chapters linger over questions of precedence; for instance, was it the French physician Alexandre Yersin or the Japanese doctor Kitasato Shibasaburo who first discovered the bacterium responsible for plague?

The book picks up speed about midway through, when Haber makes his appearance. As soon as the United States entered World War I, it, too, began manufacturing chemical weapons, among them phosgene, mustard gas, and chloropicrin. The US also developed a chemical that became known as lewisite. Lewisite, it was said, was capable of wiping out “every vestige of life—animal and vegetable.” A hundred and fifty tons of the poison were en route to Europe when the Armistice was signed in November 1918.

After the war, the scientists who had been put to work in the army’s Chemical Warfare Service had to find something else to do. The group devoted itself to creating synthetic pesticides. Then came another war.

The insecticidal properties of DDT were discovered by a Swiss chemist named Paul Müller just as the Germans were invading Poland, in 1939. (Müller, too, was awarded a Nobel Prize, in 1948.) At the time the Allies learned about the finding, in 1942, it wasn’t known whether the chemical could be safely applied to human skin, and so, in the middle of World War II, the US conducted tests, using conscientious objectors as the subjects. A hundred body lice were placed in each man’s underwear and allowed to reproduce. Every two weeks, the men were doused with DDT in varying concentrations. The army decided that DDT was safe enough to dust on people and virtually everything else, and began applying it in fantastic quantities. In an effort to avert a typhus epidemic, US troops applied DDT powder to nearly two million Italians. To prevent GIs from contracting malaria, the army dropped DDT on islands in the Pacific. Troops, refugees, displaced persons—all were sprayed with DDT. The chemical is now considered an endocrine disruptor, as well as a possible carcinogen.

Meanwhile, the Nazis, too, were searching for new pesticides, which, they knew, could often double as chemical weapons. A German chemist named Gerhard Schrader, tinkering with the structure of a toxic compound, chloroethyl alcohol, came up with a new class of insecticides that would become known as organophosphates. (Organophosphate pesticides include parathion, chlorpyrifos, and diazinon.) Tinkering with organophosphates, he came up with tabun, a nerve agent that can cause death within minutes, and sarin, a nerve agent that’s even more deadly. (The Nazis produced both tabun and sarin but never used them, for reasons that are still debated.) When Germany was close to surrendering, the Chemical Warfare Service learned about tabun and had hundreds of tons of the stuff shipped to the US. It also began recruiting Nazi chemists in an effort to thwart the Soviets in their search for new toxins. Schrader was arrested in March 1945. He cooperated with Allied investigators and produced two reports: an unclassified one on organophosphate insecticides and a classified one on organophosphate nerve gases.


Following the war, the production of organophosphate insecticides and of DDT, an organochloride pesticide, soared. The damage these chemicals did not just to “pests” but to any other living things that came in contact with them prompted Rachel Carson to write Silent Spring, published in 1962. “The question,” Carson observed, “is whether any civilization can wage relentless war on life without destroying itself, and without losing the right to be called civilized.” Silent Spring documented that synthetic pesticides were causing mortality in fish, birds, and, in extreme cases, people. (Parathion, an organophosphate, was, Carson wrote, responsible for hundreds of accidental deaths each year.) The book was a sensation, and it led to a series of legislative and regulatory changes. Von Hippel ends The Chemical Age with a chapter on its aftermath. For all of Silent Spring’s influence, he argues, the habit of solving problems with chemicals that introduce new problems persists. A good example of this comes from neonicotinoid pesticides.

Since the 1960s, neonicotinoids, which include imidacloprid and dinotefuran, have, to a significant extent, replaced organophosphates and organochlorides. Neonics, as they’re often called, were supposed to be the ideal alternative to older generations of chemicals, as their toxicity to mammals is relatively low. Neonics are now so widely used that the world is basically awash in them.

Unfortunately, neonics don’t affect just targeted insects; they affect all insects, including many of the pollinators that the world’s flowering plants depend on. It’s been hypothesized that they are at least partially responsible for the alarming crash in insect numbers that has recently been documented in places as varied as Germany and Costa Rica. And, just as with earlier generations of pesticides, neonics are having effects up and down the food chain. A study published last year in Science found that application of neonicotinoids to rice fields led to a dramatic decline in the food available for fish in Lake Shinji, north of Hiroshima, which, in turn, led to the collapse of the lake’s smelt fishery. Birds are major consumers of insects, so, indirectly, neonics are likely killing them, too. A recent paper by two entomologists in the Proceedings of the National Academy of Sciences observed:

DDT offers a close analogy to the current debate over neonicotinoids. By the time governments and companies had curtailed DDT use, the ecological and human health effects were indisputable and in some cases irreversible.

With neonicotinoids, von Hippel writes, “chemists produced a class of insecticides that kills pollinators and predators of pests, and thereby puts at risk the very crop production that the insecticides were designed to protect.”

François Jarrige and Thomas Le Roux, cowriters of The Contamination of the Earth, are also interested in the ways one set of dangerous chemicals replaces another in a recurring cycle. And they, too, identify World War I as a turning point—the start of what they call the “toxic age.” Haber again makes an appearance, but this time it’s a brief one. Jarrige, a lecturer at the University of Burgundy, and Le Roux, an environmental historian at the French National Center for Scientific Research, aren’t concerned with individual battles or discoveries so much as with the economic and social forces that generate and respond to “pollutions.” (The pair insist on using the term in the plural; one has to assume this sounds better in the original French.) “Pollutions have become a decisive element in the functioning of the capitalist world-system,” they write. “To follow these pollutions’ historical trajectory is therefore also to think about the conflicts and organizations of powers in the industrial age.”

Wars are destructive of the natural world, pretty much by definition. According to Jarrige and Le Roux, the impact of artillery fire in World War I on the French landscape was so great that it “corresponded to 40,000 years of natural erosion.” But what really distinguished World War I, by their account, was the way resource extraction became central to conflict. Moving troops and matériel now demanded vast quantities of fuel; between 1910 and 1920, global oil production more than doubled. (In 1917 the French prime minister Georges Clemenceau warned President Woodrow Wilson that if he didn’t want to lose the war, he’d better supply the Allies with petrol.) The war also gave rise to a whole new energy-intensive industry: aviation. From 1914 to 1918, the number of aircraft in the world increased by a factor of forty. Aviation, in turn, demanded aluminum, which had to be smelted, producing another polluting industry. (Among other things, aluminum production generates huge amounts of bauxite residue, or “red mud,” which is so alkaline it can kill any plant or animal that comes into contact with it.) The poison gases developed for the war, which were then repurposed as pesticides, led to still another form of pollution.

World War II accelerated the trends World War I had set in motion. Between 1939 and 1945, global aluminum production tripled. In the US it increased eightfold. After the war, aluminum manufacturers had to find something to do with all their capacity and went looking for new markets. Someone—Jarrige and Le Roux do not say who—came up with the idea of putting soda in aluminum cans, and the cans became both instruments and symbols of mass consumption.

To the growing list of “pollutions,” World War II added nuclear contamination. The bombings of Nagasaki and Hiroshima killed more than 100,000 people more or less instantaneously. The impact of the hundreds of aboveground nuclear tests that followed has been more difficult to quantify, but those effects still linger. The US tests over Bikini Atoll made the islands uninhabitable. The Soviet tests at the Polygon, also known as the Semipalatinsk test site, in Kazakhstan, rendered it one of the most radioactive places on earth.

Jarrige and Le Roux argue that the wars of the twentieth century fundamentally altered the relationship of man and nature “by initiating new industrial trajectories” and disseminating “new toxic products.” At the same time, they maintain, “these wars should not be analyzed as aberrant phases; rather, they radicalized polluting practices that existed in times of peace and that, in the emergency of conflict, found new horizons in which to unfold.”

Presumably, poison gas, organophosphates, and nuclear fission would eventually have been developed, even without two world wars. But if there’s one thing we’ve learned since the start of “the chemical age,” it’s that the rate of environmental change matters almost as much as its magnitude. Had the major powers not rushed headlong into producing CFCs and soda cans, chemical weapons and chemical fertilizers, nuclear bombs and aboveground nuclear tests, at least we might have had time to learn from our mistakes and limit the damage. Instead, Jarrige and Le Roux observe, we got what “looks like a runaway race into the abyss.” As Carson put it in Silent Spring: “Time is the essential ingredient; but in the modern world there is no time.”

An earlier version of this article incorrectly stated that Otto Hahn received the Nobel Prize in physics.