War of Nerves Read online

  At Schrader’s bench, a round-bottom flask immersed in a hot-water bath gave off a ribbon of steam into a condenser tube, which distilled the reaction product into drops of clear, colorless liquid. As always, he felt a pleasant tingle of anticipation as a new substance emerged from the synthetic process. Schrader, thirty-three, had a pale moon face, shrewd eyes framed by oversized glasses, dark hair slicked over a broad forehead, prominent cheeks, and a wide, amiable mouth. His personality was ideally suited to research, combining imagination and cleverness with an equal measure of determination and dogged persistence.

  Schrader had grown up in a religious Protestant home and had enjoyed a sheltered and pleasant childhood. In October 1928, after completing his doctoral degree in chemical engineering at the University of Braunschweig, he had joined the research staff at the Bayer Company, a subsidiary of IG Farben. Although he had specialized in inorganic chemistry in graduate school, his work at Bayer focused exclusively on organic (carbon-based) compounds. Despite his young age, he was put in charge of a dyestuffs development laboratory at the company branch in Elberfeld, a town in the industrial Ruhr Valley. The year 1928 was eventful for Schrader in other ways as well. Around Christmastime, he became engaged to Gertrud Ahlers. They married in early 1929, and a year later his first daughter, Wiebke, was born.

  After spending just two years at Elberfeld, Schrader was transferred to the main Bayer research laboratory in Leverkusen to work on naphthol dyes. In 1934, when the young Otto Bayer took over the leadership of the research department, he gave Schrader a new assignment, as head of the plant-protection group. Meanwhile, Schrader had purchased a house with a large garden in the village of Lützenkirchen. After a long day in the laboratory, he enjoyed relaxing after work in his rural idyll, surrounded by berries, fruit, vegetables, and free-roaming chickens. It was there, in April 1935, that his second daughter, Kristin, was born.

  At Leverkusen, Schrader dove into the new field of synthetic pesticides with energy and enthusiasm. Beginning in 1933, the German Reich had sought to reduce its dependence on food imports, and the loss of the large territories in the East after World War I meant that the size of the grain harvest had to be expanded considerably. To improve crop yields, the German Reich had purchased 30 million marks’ worth of pesticides from overseas, and it now sought industry’s assistance in developing a cheaper domestic alternative. Otto Bayer gave Schrader’s plant-protection group the task of developing a nonflammable fumigant that could destroy weevils in grain silos, as well as fleas in ships and living rooms. A huge potential market existed for such products because the main fumigants then in common use, ethylene oxide and methyl formate, could cause explosions in silos and other confined spaces.

  Schrader was aware that organic compounds containing the element fluorine were generally toxic, making them good candidates for new insecticides. He therefore began to introduce fluorine into a wide variety of organic molecules. As Schrader and his team synthesized one new substance after another, he provided samples to Dr. Hans Kükenthal, a biologist at Leverkusen, who tested them for insecticidal activity.

  The first set of compounds to emerge from Schrader’s lab had a strong irritant effect on the eyes and the lungs, making them of no practical value as insecticides. He therefore moved on to organic compounds containing atoms of fluorine and sulfur. One such molecule appeared to be an effective fumigant against insect pests, but further testing showed that it was absorbed by the treated grain, rendering the food unfit for human consumption. When Schrader tried to exploit this defect by developing the toxic grain as a rat poison, he found that the absorbed chemical gradually evaporated, reducing the grain’s toxicity over time. Once again, a promising line of research had led to a dead end.

  Undaunted by these setbacks, Schrader and his coworkers continued their systematic synthesis of new carbon compounds containing sulfur as the central atom. Although many of these chemicals were toxic to insects, none met the standards of safety and stability required of a commercial insecticide. Schrader next decided to work on molecules containing phosphorus, the element next to sulfur in the periodic table. Because the two elements had similar chemical properties, he reasoned that compounds containing phosphorus might also be toxic to insects. In making this intuitive leap, Schrader also drew on the earlier work of chemist Willy Lange and his student Gerda von Krüger at the University of Berlin. In 1932, Lange and Krüger had synthesized some phosphorus-containing organic compounds that appeared to offer promise as insecticides. In 1935, however, Lange was forced to leave academia because he had a Jewish wife.

  Schrader and his team proceeded to synthesize a series of organic molecules consisting of a central phosphorus atom with four bonds extending out from it like arms, each holding a different atom or cluster of atoms. One of these “organophosphate” compounds showed promising insecticidal activity: a water solution containing only 0.2 percent of the substance, sprayed on leaf lice, killed all of the insects on contact. IG Farben management considered the new compound sufficiently promising to patent it in Germany, the United States, England, and Switzerland.

  Schrader and his team spent the next year searching for a more potent version of this molecule by synthesizing hundreds of structural variants, or “analogues,” which were then screened for insecticidal activity. The researchers discarded all analogues that had low potency, were chemically unstable, gave poor synthetic yields, or required ingredients that were not available in sufficient quantities. This method of systematic trial and error was extremely labor-intensive.

  Because cyanide—a carbon atom bound to a nitrogen atom—was a poison in its own right, Schrader decided to incorporate it into the structure of the phosphorus compound. After performing the initial synthesis in November 1936, he began to experience some highly unpleasant physiological effects, including headache, poor concentration, and shortness of breath. He also noticed a marked dimming of his visual field and difficulty with visual accommodation, the process of adjusting focus from a close object to a distant one. The visual impairment worsened until it became impossible for him to read under an electric lamp.

  As Schrader drove home one evening to Lützenkirchen in his black-and-yellow Hanomag sedan, his vision had dimmed to the point that he could barely make out the road in front of him. His head throbbed and he felt painfully short of breath, with a feeling of pressure in his larynx. After reaching the house with great difficulty, he examined his eyes in a mirror and discovered that his pupils had constricted to pinpoints, giving him an eerie, zombielike appearance. Alarmed but intrigued by this phenomenon—the scientist in him was ever present—he discovered that his pupils failed to dilate in response to low light. Over the next few days, Schrader’s symptoms worsened and he had to spend two weeks in the hospital before his vision recovered fully. After his release, he spent another eight days recuperating at his parents’ home.

  Returning to the laboratory shortly before Christmas, Schrader resumed work on the cyanide-containing compound. On December 23, 1936, the synthesis and purification process was nearing completion. Distillation of the final product yielded a clear, colorless liquid with a faint scent of apples, which Schrader termed Preparation 9/91. He gave a small sample of the substance to Dr. Kükenthal, who found that an extremely dilute solution—one part in 200,000—killed 100 percent of leaf lice on contact. Preparation 9/91 was a hundred times more potent than the original compound, and far more effective than anything Schrader’s research group had developed before.

  It also became clear that the highly unpleasant symptoms Schrader had experienced in November had been caused by exposure to the new substance. Although its mild, fruity odor made it seem benign, Schrader and his assistant Karl Küpper discovered upon further investigation (now carried out with extreme caution) that inhaling fumes from even a tiny drop, spilled by accident on the laboratory bench, gave rise in minutes to a cluster of striking physiological effects: strong irritation of the cornea, marked dimming of the visual field, and an oppres
sive feeling of tightness in the chest, as if a band were being constricted around it. Staying away from the lab for a few days and breathing fresh air caused most of the symptoms to vanish, although the impaired vision recovered only gradually.

  As soon as Schrader and Küpper resumed work with Preparation 9/91 in January 1937, however, the unpleasant symptoms returned. Indeed, the two chemists had become hypersensitive, so that even the slightest whiff of the substance provoked the same array of symptoms. Küpper became agitated and feared he was losing his sight, and Schrader also worried that they were being slowly poisoned. This time they were forced to suspend their work in the laboratory for more than two weeks.

  Intrigued by the powerful physiological effects of “this new and interesting substance,” Schrader sent a letter on February 5, 1937, to Professor Eberhard Gross, the director of industrial hygiene at IG Elberfeld. At Gross’s request, he sent a sample of Preparation 9/91 for toxicological testing. Meanwhile, Schrader continued to synthesize additional variants of the cyanide compound, and in March he and Kükenthal applied for a patent on this new class of insecticide.

  In early May, Schrader received a lengthy report from Dr. Gross on the toxicity of Preparation 9/91 in mice, guinea pigs, rabbits, cats, dogs, and apes. Gross had renamed the compound Le-100, “Le” being an abbreviation for Leverkusen. In the experiments on apes, which are physiologically closest to humans, injecting as little as a tenth of a milligram of Le-100 per kilogram of body weight had given rise to dramatic toxic effects, including nausea, vomiting, constriction of the pupils and the bronchial tubes of the lungs, copious drooling and sweating, abdominal cramps, diarrhea, muscular twitching, gasping for air, violent convulsions, slowing of respiration and heartbeat, and finally paralysis of the breathing muscles, culminating in death.

  Dr. Gross’s laboratory also had a hundred-cubic-meter gas chamber suitable for inhalation experiments with large primates. It was made of glass and concrete bricks that were coated with rubber to permit a thorough cleaning. For security reasons, the gas chamber was accessible only through doors on the second and third floors of the laboratory, which were kept locked at all times. Gross had utilized the gas chamber to expose apes to Le-100 vapors at a concentration of 25 milligrams per cubic meter. After inhaling the vapor, all of the animals had convulsed and died in a time interval ranging from sixteen to twenty-five minutes.

  Schrader was disappointed by the toxicology results because Le-100 was far too poisonous to warm-blooded animals to be marketed as a commercial insecticide. Nevertheless, IG Farben brought the new compound to the attention of the German government. According to an official Reich ordinance of 1935, all new discoveries and patents of potential military significance were to be reported to the War Office, which was empowered to classify any invention that might be useful for the nation’s defense. Toxic industrial chemicals were of interest as chemical warfare agents, particularly since August 1936, when Hitler had ordered the armed forces (Wehrmacht) to prepare for war by 1940. German companies had already submitted more than a hundred compounds for evaluation.

  A few influential figures within the Wehrmacht and the chemical industry viewed poison gas as a militarily “decisive” weapon. They noted that Benito Mussolini had employed chemical weapons extensively in 1935 and 1936 during the Italian conquest of Abyssinia (Ethiopia), using aircraft to drop mustard-filled bombs on Emperor Haile Selassie’s army. Most of the Abyssinian fighters had been barefoot tribesmen lacking gas masks and protective clothing, making them extremely vulnerable to mustard. Although the chemical attacks had been a flagrant violation of the 1925 Geneva Protocol, to which Italy was a party, the League of Nations had done nothing to stop them.

  Among the leading German proponents of chemical warfare was Dr. Heinrich Hörlein, the director of pharmaceutical research at IG Elberfeld. A physician by training, he had been involved in developing poison gases since 1933 and routinely advised the German Army on technical matters. After reading Dr. Gross’s report on the mammalian toxicity of Le-100, Dr. Hörlein forwarded a copy to the Army Ordnance Office (Heereswaffenamt), which was responsible for the development, testing, production, and procurement of land weapons.

  Within the Army Ordnance Office, the Weapons Development and Testing Department (Waffenprüfamt) was organized into several divisions. Division 9 (Wa Prüf 9), headquartered in the Charlottenburg district of Berlin and directed by Lieutenant-Colonel Dr. Kurt Rüdiger, specialized in the development and testing of chemical warfare agents, munitions, and protective equipment. In April 1937, Dr. Leopold von Sicherer, a senior official in Division 9, read Gross’s report on Le-100 and, intrigued, requested a demonstration of the new compound. A few days later, Sicherer visited Gross’s laboratory at Elberfeld, accompanied by Dr. Wolfgang Wirth, a specialist in pharmacology and toxicology at the Army Ordnance Office who had earlier worked at Tomka.

  Dr. Gross demonstrated the effects of vaporized Le-100 on caged laboratory mice. Whereas standard chemical warfare agents such as phosgene and mustard took several hours to kill, exposure to small amounts of the new compound caused mice to go into convulsions and die within twenty minutes. Sicherer and Wirth concluded that Le-100 was a “remarkable compound” with great military potential. In early May, not long after the demonstration at Elberfeld, they invited Schrader to Berlin to demonstrate the synthesis of Le-100.

  THE GERMAN ARMY’S Gas Protection Laboratory (Heeresgasschutzlaboratorium) was housed in Spandau Citadel, a brick fortress perched on a small island at the junction of the Havel and Spree Rivers in northwest Berlin. Although only the crenellated Julius Tower remained from the original structure, which had been built around 1200, the fortress had been greatly enlarged during the sixteenth century. Its layout was that of a square keep, with the four corners shielded by massive stone bastions in the form of arrowheads. One side of the citadel abutted the river, while the other three walls were surrounded by a moat covered with lily pads.

  The name of the Army Gas Protection Laboratory was deliberately misleading. In fact, the roughly three hundred scientists and technicians worked not only on chemical warfare defense but also on the development of new agents and production methods. To accommodate the necessary facilities and equipment, numerous renovations had been made to the historical buildings inside the Citadel and four large new structures had been erected. The area beyond the entrance gate and the administration building was a military zone that was restricted and secured by an additional fence. Building 4, near the west curtain wall, contained a technical library and laboratories for the analysis and synthesis of chemical warfare agents; Building 6 was for work on chemical munitions and the development and testing of protective equipment; Building 8 contained pilot plants for producing up to 50 kilograms of agents for testing purposes; Building 14 did studies on the aerosolization of liquid agents; Building 15 was the human medical department and the staff clinic; and Building 15A housed the toxicological institute, which performed testing on a wide variety of experimental animals. The historical Armory (Zeughaus) was where manufacturing processes for chemical warfare agents were developed, and munitions testing took place in two explosive test chambers built of reinforced concrete next to the north curtain wall.

  Schrader passed through a guard post and then crossed a bridge over the moat that led to the main gate. At the headquarters building, an officer checked his identity papers and escorted him to his appointment in Building 4. Much to Schrader’s relief, the officers at Spandau wore army drab rather than the intimidating black uniforms of the Schutzstaffel (SS). Present at the meeting were Dr. Sicherer and Lieutenant-Colonel Rüdiger of Division 9 and Dr. Hans-Jurgen von der Linde, the chief of the Army Gas Protection Laboratory. After introductions had been made, Schrader described the properties of Le-100 and its remarkable physiological effects.

  The Army scientists were deeply impressed by the potency of Le-100. One of them said that the new poison was “taboo” (tabu in German), meaning that it was too strong, and as a result
it was named “Tabun.” Schrader had discovered accidentally what many others had tried to develop deliberately. From 1925 to 1931, the Reichswehr had funded chemical weapons research at twelve German universities and institutes. Later, Army chemists at Spandau had searched the technical literature and pending industrial patents for references to highly poisonous compounds. Yet no substance had been identified that even approached the toxicity of Tabun.

  Dr. Sicherer decided that the IG Farben patent for Tabun would henceforth be classified top secret and that the Army would take charge of the compound’s further development. In recognition of their work, Schrader and Gross received a reward of 50,000 marks. Schrader was requested to synthesize one kilogram of Tabun and send it to Spandau for preliminary testing. In the meantime, Dr. Rüdiger would arrange to remodel one of the chemical laboratories in the basement of the Citadel and install a modern apparatus for pilot-scale production.

  IG Farben welcomed the Army’s decision to assume responsibility for the further development of the new agent, for two reasons. First, the company could not manufacture highly toxic substances in its existing factories, all of which were located in densely populated areas. Second, it would be impossible for the firm to maintain a high level of secrecy about a chemical such as Tabun, tiny amounts of which produced striking physiological effects such as pinpoint pupils. In order to disguise the identity of the compound further, the Army developed a series of military code names for Tabun, including “Gelan,” “Substance 83,” and finally “Trilon 83” (or T-83), after a popular brand of laundry detergent manufactured by IG Farben.