Most people looked upon chemical warfare as abhorrent. In a June 1943 speech, President Roosevelt himself had said that using chemicals to kill people was immoral and inhumane. The president had denied Chemical Warfare Service officials their request to change the service’s name to the Chemical Corps because of the permanence the name change suggested. And yet here was the interesting news for the Chemical Service. When German nerve gas entered into the world of chemical warfare, it brought with it the assurance of a U.S. chemical warfare program in peacetime. According to chemical weapons expert Jonathan B. Tucker, “In 1945, in the aftermath of World War II, the U.S. Army Chemical Warfare Service decided to focus its research and development efforts on the German nerve agents, the technological challenges of which promised to ensure the organization’s survival through the period of postwar demobilization and declining military budgets.” Within several months of the German surrender, 530 tons of tabun nerve agent were shipped to the United States and used in Top Secret field tests.
Requests to bring German chemists to the United States for weapons work quickly followed. But, as had been the case with the V-2 rocket scientists, the notion of issuing visas to Hitler’s chemists was met with hostility inside the State Department. When the chief of the State Department’s Passport Division, Howard K. Travers, learned about this idea, he sent his colleagues an internal memo stating, “We should do everything we consistently can to prevent German chemists and others from entering this country.”
In Germany, Alsos scientific director Samuel Goudsmit had been tracking Hitler’s chemists ever since the Allies crossed the Rhine. Likewise, the CIOS chemical weapons team, led by Lieutenant Colonel Philip R. Tarr of the U.S. Chemical Warfare Service and his British counterpart Major Edmund Tilley, were continuing their relentless pursuit. When Alsos located the chemist Richard Kuhn at the Kaiser Wilhelm Institute for Medical Research in Heidelberg, they paid him a visit. Kuhn had once been an internationally revered organic chemist, but rumor had it that he had become an ardent Nazi during the war. Kuhn won the Nobel Prize in Chemistry in 1938 but turned down accepting the award at the request of Hitler, who called it a Jewish prize. Here now to interview Richard Kuhn, Samuel Goudsmit had with him two American chemists, Louis Fieser of Harvard and Carl Baumann of the University of Wisconsin. Both men had actually worked with Kuhn in his laboratory before the war. After a cordial exchange of greetings, the interrogation began. Alsos sought information regarding the Third Reich’s nerve agent program. What did Herr Kuhn know?
Kuhn, with his mop of straight reddish-brown hair, cunning smile, and schoolboy looks, swore that he had no connection whatsoever with Reich military research. He told his former colleagues that he was a pure scientist, an academic who spent the war working on the chemistry of modern drugs. Samuel Goudsmit had his doubts. “Richard Kuhn’s record did not seem too clean to me,” Goudsmit recalled after the war. “As president of the German Chemical Society he had followed the Nazi cult and rites quite faithfully. He never failed to give the Hitler salute when starting his classes and to shout ‘Siegheil’ like a true Nazi leader,” Goudsmit recalled. But the Alsos leader did not have enough evidence to have Kuhn arrested, so he put him under surveillance instead.
Elsewhere in Germany, CIOS chemical weapons investigators Colonel Tarr and Major Tilley had been rounding up German chemists and sending them to prisoner-of-war facilities near where the individual arrests had taken place. Starting on June 1, 1945, these chemists would now be sent to a single location—a Top Secret interrogation facility outside Frankfurt. SHAEF was moving its headquarters from Versailles to Frankfurt and was to be dissolved in mid-July. The new organization in charge of all affairs, including scientific exploitation, was the Office of Military Government for Germany (OMGUS), whose commander was Eisenhower’s deputy General Lucius D. Clay. The Allies were also reorganizing the way in which scientific intelligence was going to be collected moving forward. CIOS was transitioning into American and British components: FIAT (Field Information Agency, Technical) and BIOS (British Intelligence Objectives Sub-committee). CIOS teams would remain active while they completed open investigations.
The structure that housed this new interrogation center was none other than Schloss Kransberg, or Kransberg Castle, Hermann Göring’s former Luftwaffe headquarters and the place where Albert Speer and his aide spent the night the last New Year’s Eve of the war. The Allies gave it the code-name Dustbin. This medieval structure built high in the Taunus Mountains had grand rooms, hardwood floors, beautiful stone fireplaces, and shiny chandeliers. These were hardly gulag-type quarters. In terms of security classification, Dustbin was top-tier. The facility was the second-most classified interrogation center after Ashcan. Dustbin was self-contained inside its centuries-old stone walls, and, as it went at Ashcan, the prisoners here were free to roam the grounds and chat among themselves. Karl Brandt, Hitler’s doctor, organized morning gymnastics classes in the garden. Others played chess. Industrialists held lectures in the large banquet hall that Göring had once used as a casino. Speer took walks in the castle’s apple orchard, almost always alone by choice. Whereas Ashcan housed the Nazi high command, Dustbin had many Nazi scientists, doctors, and industrialists under guard. This included more than twenty chemists with IG Farben and at least six members of its board.
Throughout the early summer of 1945, several key players in Farben’s tabun gas program were still at large. For Major Tilley, the chronology regarding how Farben first began producing nerve gas and how it transformed into wide-scale production remained a mystery until a Farben chemist named Dr. Gerhard Schrader was captured and brought to Dustbin. Schrader was the man who created the nerve agent that had been found at Raubkammer, the Robbers’ Lair. The information Schrader had was among the most sought-after classified military intelligence in the world. Tilley prepared for intense stonewalling from the Farben chemist. Instead Dr. Schrader spoke freely, offering up everything he knew, beginning with tabun’s startling discovery in the fall of 1936.
Dr. Schrader had been working at an insecticide lab for IG Farben in Leverkusen, north of Cologne, for several years. By the fall of 1936, he had an important job on his hands. Weevils and leaf lice were destroying grain across Germany, and Schrader was tasked with creating a synthetic pesticide that could eradicate these tiny pests. The government had been spending thirty million reichsmarks a year on pesticides made by Farben as well as other companies. IG Farben wanted to develop an insect killer that could save money for the Reich and earn the company a monopoly on pesticides.
Synthesizing organic, carbon-based compounds was trial-and-error work, Dr. Schrader told Major Tilley. It was labor-intensive and dangerous. Schrader, a family man, took excellent precautions against exposure, always working under a fume hood. Even trace amounts of the chemicals he was using had cumulative, potentially lethal effects. Schrader suffered from frequent headaches and sometimes felt short of breath. One night, while driving home after working on a new product, Schrader could barely see the road in front of him. When he pulled over to examine his eyes in the mirror, he saw that his pupils had constricted to the size of a pinhead. Over the next several days his vision grew worse. He developed a throbbing pressure in his larynx. Finally, Schrader checked himself into a hospital, where he was monitored for two weeks before being sent home and told to rest.
Eight days after the respite, Schrader returned to work. He had been developing a cyanide-containing fumigant, which he had given the code name Preparation 9/91. Picking up where he’d left off with his work, he prepared a small amount of his new substance, diluting it to 1 in 200,000 units to see if it would kill lice clinging to leaves. He was stunned when his new creation killed 100 percent of the lice. Schrader repeated the experiment for his colleagues. They all agreed that Preparation 9/91 was a hundred times more lethal than anything anyone at the Leverkusen lab had ever worked with before.
Dr. Schrader sent a sample of this lethal new fumigant to Farben’s director of industri
al hygiene, a man named Professor Eberhard Gross (not to be confused with Dr. Karl Gross, the Waffen-SS bacteriologist connected with the Geraberg discovery). Gross tested the substance on apes and was duly shocked by the results. After a healthy ape was injected with a tiny amount of Preparation 9/91—just 1/10th of a milligram per kilo of body weight—the ape died in less than an hour. Next, Gross tested the substance on an ape inside an inhalation chamber. He watched this healthy ape die in sixteen minutes. Professor Gross told Dr. Schrader that his Preparation 9/91 was being sent to Berlin and that he should wait for further instruction on what action to take next.
At Dustbin, Schrader told Major Tilley that when he learned his compound could kill a healthy ape through airborne contact in minutes, he became upset. His discovery was never going to be used as an insecticide, Schrader lamented. It was simply too dangerous for any warm-blooded animal or human to come into contact with. Schrader said his goal was to save money for the Reich. With the news of how powerful Preparation 9/91 was, Schrader felt he’d failed at his job. He got back to work, searching for a fumigant better suited for the task of killing weevils and leaf lice.
Meanwhile, Professor Gross brought the substance to his superiors. Starting in 1935, a Reich ordinance required all new discoveries with potential military application to be reported to the War Office. The Reich’s Chemical Weapons Department began to evaluate Schrader’s Preparation 9/91 for its potential use in chemical warfare. In May 1937 Schrader was invited to Berlin to demonstrate how he’d synthesized Preparation 9/91. “Everyone was astounded,” Schrader told Tilley. This was the most promising chemical killer since the Germans invented mustard gas. Preparation 9/91 was classified Top Secret and given a code name: tabun gas. It came from the English word “taboo,” something prohibited or forbidden.
Dr. Schrader was told to produce one kilogram for the German army, which would take over tabun production on a massive scale. Schrader got a bonus of 50,000 reichsmarks (the average German worker during this time period earned 3,100 reichsmarks a year) and was told to get back to work. Farben still needed him to develop a lice-killing insecticide.
With their new nerve agent tabun, Farben executives saw all kinds of business opportunities. Karl Krauch, the head of Farben’s board of directors, began working with Hermann Göring on a longer-range plan to arm Germany with chemical weapons, ones that could eventually be dropped on the enemy from airplanes. In his report to Göring, Krauch called tabun “the weapon of superior intelligence and superior scientific-technological thinking.” The beauty in the nerve agent, Krauch told Göring, was that it could be “used against the enemy’s hinterland.” Göring agreed, adding that what he liked most about chemical weapons was that they terrified people. He responded to Krauch in writing, noting that the deadly effects of nerve agents like tabun gas could wreak “psychological havoc on civilian populations, driving them crazy with fear.”
On August 22, 1938, Göring named Karl Krauch his Plenipotentiary for Special Questions of Chemical Production. Farben was now positioned to build the Reich’s chemical weapons industry from the ground up. The Treaty of Versailles had forced Germany to destroy all its chemical weapons factories after World War I, which meant factories had to be secretly built. This was an enormous undertaking, now an official part of the Nazis’ secret Four Year Plan, and through Krauch IG Farben was made privy to the Reich’s war plan before war was declared.
At the Dustbin interrogation center, Major Tilley asked Schrader about full-scale production. Based on the Allies’ discovery of thousands of tons of tabun bombs in the forests outside Raubkammer, Farben must have had an enormous secret production facility somewhere. Dr. Schrader said that he was not involved in full-scale production. That was the job of his colleague, Dr. Otto Ambros.
Major Tilley asked Schrader to tell him more about Ambros. Schrader said that most of what Ambros did was classified but that if Major Tilley wanted to know more about what he actually did for Farben, Tilley should talk to individuals who sat on Farben’s board of directors with Ambros, either Dr. Karl Krauch or Baron Georg von Schnitzler. Both men were interned here at Dustbin.
“Who is Mr. Ambros?” Major Tilley asked Baron Georg von Schnitzler, in an interview that would later be presented as evidence in a Nuremberg war crimes trial.
“He is one of our first, younger technicians,” von Schnitzler said. “He was in charge of Dyhernfurt [sic] as well as Auschwitz and Gendorg [sic].”
Where was Ambros now? Tilley asked von Schnitzler. The baron told Major Tilley to talk to Karl Krauch.
From Krauch, Major Tilley learned quite a bit more about Ambros. That he had been in charge of technical development of chemical weapons production at Gendorf and at Dyhernfurth. That Gendorf produced mustard gas on an industrial scale, and that Dyhernfurth produced tabun. Krauch also revealed a new piece of evidence. Dyhernfurth produced a second nerve agent, one that was even more potent than tabun, called sarin. Sarin was an acronym pieced together from the names of four key persons involved in its development: Schrader and Ambros from IG Farben and, from the German army, two officers named Rüdiger and Linde. Krauch told Major Tilley that the Dyhernfurth plant had fallen into Russian hands.
Karl Krauch said something else that caught Major Tilley by surprise. Before coming to Dustbin, Krauch said he had been in the hospital, where he’d been paid a visit by two American officers, one of whom was Lieutenant Colonel Tarr. “Judging from conversations I had a few months ago in the hospital with members of the USSBS [Colonel Snow] and Chemical Warfare [Colonel Tarr],” Krauch explained, “the gentlemen seemed mostly interested in sarin and tabun; they asked me for construction plans and details of fabrication. As far as I understood they intended to erect similar plants in the U.S.A. I told them to apply to Dr. Ambros and his staff at Gendorf.”
Major Tilley was shocked. Lieutenant Colonel Tarr was his CIOS partner, and yet Tarr had neglected to share with him the story about visiting Krauch in the hospital. This was Tilley’s first indication that Tarr was running a separate mission for the U.S. Chemical Warfare Service, one that apparently had a different objective than the CIOS mission. The full, dramatic story was about to unfold.
By June 1945, Otto Ambros had been questioned by soldiers with the Third Army numerous times. For reasons that remain obscure, no one from that division had been informed of the fact that Ambros was wanted for war crimes, or that he had served as Farben’s chief of chemical weapons production throughout Hitler’s rule. To the Third Army he was simply the “plain chemist” in the Bavarian village of Gendorf, the smiling, well-dressed businessman who supplied American soldiers with free bars of soap.
At Dustbin, Major Tilley relayed this critical new information about Dr. Otto Ambros to his FIAT superiors, who in turn sent an urgent message to the Sixth Army Group, also in Gendorf, ordering the immediate arrest of Dr. Ambros. The Sixth Army was to transport Ambros directly to Dustbin so that Major Tilley could interrogate him. A note card was placed in Ambros’s dossier. Disparate bits of information were now coming into sharp focus. “Case #21877. Dr. Otto Ambros. Rumored to have been involved in use of concentration camp personnel for testing effectiveness of new poison gases developed at Gendorf.”
CROWCASS notified SHAEF, insisting that Dr. Ambros be arrested. As the plant manager at Farben’s Buna factory at Auschwitz, Otto Ambros had been linked to atrocities including mass murder and slavery. The Sixth Army Group swung into action. But when they arrived at Ambros’s home in Gendorf, arrest orders in hand, Ambros was gone.
The first assumption was that Ambros had fled on his own. This proved incorrect. He had been taken away by Lieutenant Colonel Philip Tarr. Initially, the commanding officer at Dustbin found this impossible to comprehend. It was one thing for Tarr to try to interview Ambros before any other chemical warfare experts did. That kind of rivalry had been going on ever since the various scientific intelligence teams had crossed the Rhine. But why would Tarr defy orders from SHAEF to have Ambros arrested? While
soldiers with the Sixth Army stood scratching their heads in Gendorf, Tarr and Ambros were actually headed to Heidelberg in a U.S. Army jeep. Their destination was an American interrogation center that was run by army intelligence officers with the Chemical Warfare Service. For days, no one at Dustbin had any idea where Tarr and Ambros had gone.
Otto Ambros had a razor-sharp mind. He was cunning and congenial, sly like a fox. He almost always wore a grin. The American war crimes prosecutor Josiah DuBois described him as having a “devilish friendliness” about him. He also had a distracting, rabbitlike habit of sniffing at the air. Ambros was short and heavyset, with white hair and flat feet. He was a brilliant scientist who studied chemistry and agronomy under Nobel Prize winner Richard Willstätter, a Jew. As a chemist, Ambros had a mind that was capable of pushing science into realms previously unexplored. Few men were as important to IG Farben during the war as Otto Ambros had been.
IG Farben first began producing synthetic rubber in 1935, naming it Buna after its primary component, butadiene. In 1937 Farben presented commercial Buna on the world stage and won the gold medal at the International Expo in Paris. When Germany invaded Poland in September 1939, the Reich’s ability to import natural rubber diminished. Demand for a synthetic alternative skyrocketed, a fact Farben was well aware of in advance of Germany’s attack. Tanks needed treads, aircraft needed tires, and Farben needed to produce rubber. Hitler directed Farben to increase its Buna production further. Dr. Ambros was put in charge and saw to it that Farben opened a second and then a third Buna plant so that supply could meet demand. As the invasion of the Soviet Union was secretly conceived by the German high command, Hitler again called upon Farben’s board of directors to increase its synthetic rubber production. Farben needed to construct a massive new Buna factory. Otto Ambros was put in charge of masterminding this undertaking as well. The place chosen was Auschwitz.