The History of Biological Weapons Programs

Weapons You Cannot See

EVERY NATION THAT HAS PURSUED BIOLOGICAL WEAPONS has officially denied it. The secrecy is not incidental. It is structural: the weapons themselves are invisible, the programs are hidden from the public and often from elected officials, and the denials are almost always plausible because proof requires access to facilities that are kept tightly closed. The history of biological weapons is therefore a history of what has eventually been confirmed, usually after programs end, defectors talk, or archives open.

What has been confirmed is disturbing enough. State biological weapons programs over the past century have worked on anthrax, plague, smallpox, typhus, tularemia, Ebola, and dozens of other pathogens. They have tested these agents on prisoners, on animals, and in some cases on uninformed civilian populations. They have built production facilities capable of generating tons of biological agents per year. And they have done most of this while their governments signed international agreements prohibiting exactly what they were doing.

World War I: The First Confirmed Programs

The modern era of biological weapons begins with Germany in World War I. German agents are documented to have used glanders, a bacterial disease of horses and donkeys, to infect Allied cavalry and pack animals. Operations were conducted in Romania, the United States, Argentina, and Spain, targeting animals before they could be shipped to Allied forces in Europe.

The operations were small-scale and of limited military significance, but they established a precedent: state actors were willing to use disease as a weapon, and they could do so covertly. The revelation of German biological sabotage operations after the war contributed to the drafting of the 1925 Geneva Protocol, which prohibited the use of biological and chemical weapons in warfare. Almost every major power signed it. Almost every major power then continued developing the weapons it prohibited.

Unit 731: Japan's Systematic Atrocity

The most extensively documented biological warfare atrocities of the 20th century were committed by Japan's Unit 731, the Epidemic Prevention and Water Purification Department of the Kwantung Army, headquartered at Pingfang near Harbin, Manchuria. The unit operated from 1935 until the Soviet invasion of Manchuria in August 1945.

Unit 731 conducted experiments on prisoners, primarily Chinese civilians and prisoners of war, but also Soviet, Korean, and some Western POWs. The experiments included infecting prisoners with plague, cholera, typhoid, and anthrax, then vivisecting them while still alive to observe the disease's progress. Prisoners were also used to test frostbite treatments, flamethrowers, and the effects of pressure changes, all without anesthesia.

The death toll from Unit 731's experiments is estimated at between 3,000 and 12,000 prisoners. The unit also conducted field operations, releasing plague-infected fleas over Chinese cities and contaminating water supplies. Some historians estimate that the unit's field operations killed tens of thousands of Chinese civilians, though this remains debated.

After Japan's defeat, the United States made a decision that has been debated ever since. General Douglas MacArthur's command granted immunity from prosecution to Unit 731's leadership, including its commander Shiro Ishii, in exchange for the data from their experiments. The researchers were not tried at the Tokyo War Crimes Tribunal. The information they provided was classified and incorporated into American biological weapons research. Several former Unit 731 researchers went on to prominent careers in Japanese medicine and academia.

The United States Program: From Offense to the Nixon Decision

The United States began its offensive biological weapons program in 1943, driven by intelligence reports about Japanese and German programs. The main production facility was established at Pine Bluff Arsenal in Arkansas. Research was conducted at Fort Detrick in Maryland, which remains the center of U.S. government biological defense research today.

The U.S. program worked on anthrax, botulinum toxin, brucellosis, Q fever, and Venezuelan equine encephalitis, among other agents. Production facilities were built that could generate these agents in large quantities. Weapons delivery systems were developed and tested.

President Richard Nixon terminated the U.S. offensive biological weapons program in 1969 and 1970, ordering the destruction of all stockpiles and production facilities. The decision was driven by a combination of factors: a recognition that biological weapons were strategically unreliable compared to nuclear weapons, concerns about accidents at production facilities, and the political opportunity to negotiate a multilateral prohibition that might constrain Soviet programs.

The Biological Weapons Convention of 1972 prohibited the development, production, and stockpiling of biological weapons. The United States ratified it. So did the Soviet Union.

Biopreparat: The Soviet Program That Kept Going

The Soviet Union signed the Biological Weapons Convention in 1972 and then immediately began expanding its offensive biological weapons program. Biopreparat, the nominally civilian organization that ran the Soviet bioweapons program, grew to employ approximately 60,000 scientists and researchers at its peak in the 1980s and 1990s.

What Biopreparat was doing was not discovered by Western intelligence during the Cold War. It was revealed by defectors after the Soviet Union's collapse. The most important was Ken Alibek, the former deputy director of Biopreparat, who defected to the United States in 1992 and wrote a memoir, "Biohazard," that described the Soviet program in detail.

According to Alibek and other defectors, Biopreparat developed multi-drug-resistant strains of plague and anthrax, weaponized smallpox at a time when the world believed it had been eradicated and the remaining stocks secured, created modified pathogens designed to defeat Western vaccines and antibiotics, and maintained production facilities capable of generating hundreds of tons of biological agents per year. The Vozrozhdeniya Island testing facility in the Aral Sea was used to test aerosolized agents on animals and, allegedly, on human subjects.

The 1979 Sverdlovsk anthrax outbreak, which killed at least 64 people in the Soviet city now called Yekaterinburg, was a direct product of the program. A malfunction at a military microbiological facility released anthrax spores into the air. The Soviet government maintained for years that the outbreak was caused by contaminated black market meat. Post-Soviet investigation confirmed it was an accident at a weapons production facility. The cover-up lasted over a decade.

The Accidental Releases and Near-Misses

Sverdlovsk was not an isolated incident of things going wrong. Biological weapons programs are inherently difficult to contain. The pathogens they work with do not respect facility boundaries, safety protocols, or political considerations.

In the United States, an outbreak of Q fever at Fort Detrick in 1955 infected an estimated 1,300 workers over several years. Testing of biological agents over open areas of the United States during the 1950s and 1960s, done without public knowledge or consent, exposed American civilians to experimental agents. A 1969 Senate hearing revealed that the U.S. Army had conducted 239 open-air biological and chemical warfare tests on American territory between 1949 and 1969, many of them over populated areas. The "simulants" used in some tests were later found to cause illness in people with compromised immune systems.

British testing at Gruinard Island in Scotland in 1942 contaminated the island with anthrax spores so thoroughly that it remained officially off-limits until 1990, after an extensive decontamination effort. The island is now declared safe, though the legacy of the testing program is a permanent part of its history.

The Post-Cold War Proliferation Concern

The collapse of the Soviet Union created a new kind of biological weapons threat. Biopreparat employed tens of thousands of trained scientists. Many of them lost their jobs. Some went to work for foreign governments or private entities willing to pay for their expertise. The concern about "brain drain" from the former Soviet bioweapons complex drove significant U.S. investment in the Cooperative Threat Reduction program, which tried to redirect former bioweapons scientists toward civilian research.

The concern was not theoretical. At least some former Soviet bioweapons scientists did work for countries attempting to develop similar capabilities. The specific details remain classified, but the broad pattern is documented in declassified reports and in the work of researchers like Jonathan Tucker and Milton Leitenberg who have studied weapons proliferation.

Iraq's biological weapons program, which operated through the 1980s and into the early 1990s, produced anthrax, botulinum toxin, aflatoxin, and other agents at the Al Hakam facility. Saddam Hussein denied the program existed until 1995, when his son-in-law Hussein Kamel defected and revealed its scope. The program had been discontinued before the 2003 invasion, a fact that U.S. intelligence famously failed to assess correctly.

The Verification Problem and Why It Has Not Been Solved

The Biological Weapons Convention has no verification mechanism. Unlike the Chemical Weapons Convention, which established a dedicated inspections organization, the BWC relies entirely on national declarations and voluntary compliance. There is no international body with the authority to inspect a suspected biological weapons facility, no mandatory reporting of potentially dangerous research, and no mechanism for investigating allegations of treaty violations.

This gap is not accidental. Negotiations for a BWC verification protocol collapsed in 2001, largely due to U.S. opposition. The American position, maintained under the George W. Bush administration, was that an inspections regime would expose commercial secrets in the pharmaceutical industry and would not be effective against sophisticated programs that could conceal their activities from inspectors.

The result is a treaty that prohibits biological weapons without any mechanism for ensuring compliance. Every nation can, and several probably do, maintain research programs that walk the line between defensive research (permitted) and weapons development (prohibited). The line is genuinely difficult to define. Defensive research requires working with dangerous pathogens. The knowledge gained is inherently dual-use.

The history of biological weapons programs is a history of that dual-use problem playing out under conditions of extreme secrecy, strategic competition, and institutional inertia. The programs that existed were far larger than the public knew. The programs that may still exist are, by definition, unknown. What history demonstrates is that the combination of national security imperatives and the availability of biological expertise makes the complete elimination of the threat one of the hardest problems in arms control.