• By mid-1942, word of Japanese BW development was leaking out to the Allies, and in July 1942 Winston Churchill placed the issue on the top level of priority for discussion by Allied leadership. It was not completely a new topic to him, since the British had been thinking about BW since 1934. The prime mover was a Whitehall bureaucrat named Sir Maurice Hankey, who, like Shirou Ishii, had been inspired to investigate BW by the fact that the Geneva Protocol tried to ban it.

In the prewar period, British BW efforts were minimal, consisting of a few committees issuing reports and, as war approached, funding for limited defensive measures. When war broke out in 1939, considerations for offensive biowarfare rose in importance, and the British government established a small laboratory at Porton Down, run by a medical researcher named Paul Fildes.
Fildes began to conduct small-scale experiments to evaluate pathogens and biotoxins for use as bioagents, and in late 1941 recommended the production of millions of anthrax-laced linseed cattle cakes that would be dropped by air over Germany. The goal was to destroy German livestock, not kill German civilians, though obviously some civilians would contract anthrax by eating tainted meat. Production of the cattle cakes was approved, and a large stockpile of them was stored at Porton Down until the end of the war, when they were all incinerated.
Biotoxins had a particular appeal for clandestine operations in occupied Europe, setting a precedent for later interest by intelligence services in such agents. Porton Down is known to have produced botulism toxin under the designation “BTX”. Some sources claim, though not with much support in the facts, that a BTX-laced grenade was used in 1942 to assassinate SS General Reinhard Heydrich, a senior and highly competent Nazi officer, considered a possible heir to Hitler’s throne, who was then the ruler of occupied Czechoslovakia.
The intelligence information leaking out about Japanese BW experiments only increased the priority of Allied efforts to build their own BW capability. In the summer of 1942, the British conducted their first large-scale BW experiment on Gruinard Island, off the coast of Scotland. A film was made of the experiment and remained classified until 1997. Sheep were taken to an open field, secured in wooden frames, and exposed to a bomb that scattered anthrax spores. The sheep started dying three days later. They were examined and then burned. Other tests involved dropping anthrax bombs from a Vickers Wellington bomber.
Safety precautions were slipshod and it is a wonder that there were not calamities among the personnel involved or innocent bystanders. One worker in the program recalled helping a medical researcher pour a thick soup of anthrax agent into a bomb, without use of protective clothing or any other safety measures. Despite attempts to disinfect Gruinard Island, the anthrax spores left there by the experiments kept the island in quarantine for five decades.
The final report on the Gruinard Island experiments suggested that anthrax could be used to render whole cities uninhabitable “for generations”. Biological weapons were potentially orders of magnitude more effective than chemical weapons.

  • In the meantime, the British had been working with the Canadian government to set up a BW test range at Suffield, in the province of Alberta. The area was empty and isolated, and experiments could be performed with greater safety than any location available in the British Isles.

The entry of America into the war in late 1941 added more momentum to the Allied BW effort. The US had considered BW, and government reports had been written and distributed to detail defensive and offensive measures. With a real war on, the American Chemical Warfare Service, with British assistance, built up BW research facilities, including test stations near Dugway and near Pascagoula, Mississippi; a potential production facility at Vigo, near Terra Haute, Indiana; and the master research and development center at Camp Detrick, Maryland.
The British work on anthrax, or “N” as it was codenamed, as a bioagent led in 1943 to the design of an “N” bomb suitable for mass production by the Americans. This munition weighed 1.8 kilograms (4 pounds). 106 of these “bomblets” were to be packed into a 225 kilogram (500 pound) cluster-bomb canister and dropped over enemy population centers.
The whole effort was protected by the highest level of secrecy, TOP SECRET:GUARD, which the Americans described jokingly as DESTROY BEFORE READING. An initial pilot batch of 5,000 N bombs was produced at Camp Detrick in May 1944, and medium-scale production at a rate of about 50,000 bomblets a month followed. The bomblets were turned over to the British, who stockpiled them.
The plant at Vigo, Indiana, was designed for production of 500,000 anthrax bombs per month. The plant was never put into operation, partly because of extreme safety concerns. By the end of the war, it had been converted to antibiotic production, though it could have easily been converted back to bioagent manufacture if the need had arisen.

  • The drastic nature of anthrax was not lost on the Americans, and so they searched for a bioagent that could incapacitate instead of kill. They found brucellosis a promising agent. The infectious dose was much smaller than that of anthrax, meaning a single bomber could attack a much larger area with the same weight of bombs, and a city that had been attacked with brucellosis would be safe to enter a week or so after the attack. Brucellosis was, on the other hand, wildly infectious, and many of the people who worked with it in the weapons development program came down with it. However, other than a few days of nasty chills, pains, fever, and headaches, it rarely did much harm. Brucellosis weapons were in an advanced state of development at the end of the war.

The Americans also investigated anti-crop bioagents, including “potato blights” and “wheat rusts”; “sclerotium rot”, which can attack soybeans, sugar beets, sweet potatoes, and cotton; and “blast diseases” to attack rice. There is some suspicion that crop bioagents might have been used by the Allies. In the fall of 1944, the German potato crop was infested by a huge plague of Colorado beetles, and in 1945 the Japanese rice crop was badly afflicted by rice blast. However, in the absence of any evidence supporting such suspicions, there is no reason to believe these incidents were due to anything but natural causes.