United States Biological Overview

This page is part of the United States Country Profile.

During World War II and the Cold War the United States developed an extensive offensive biological warfare (BW) program that incorporated a wide-variety of anti-personnel, anti-crop, and toxin weapons armed with, among others, Bacillus anthracis (anthrax) and Coxiella burnetii (Q-fever). However, President Richard Nixon unilaterally abolished this program on 25 November 1969 following an extensive policy review.

The United States has not possessed an offensive BW program since that time and thus was already in compliance with the Biological and Toxin Weapons Convention (BTWC) before formally ratifying it in 1975. Although the U.S. biodefense program has at times generated controversy, the United States continues to play an important role in furthering global norms against the proliferation of biological weapons.

U.S. biological weapons efforts began after World War I with limited research and development (R&D) of the toxin ricin. The United States Chemical Warfare Service (CWS) explored adhering the toxin to bullets and disseminating it as an aerosol. ¹ However, findings from this R&D were never utilized. ²

In the early 1940s the United States took steps to acquire a robust BW program, because its intelligence community came to believe that Germany had its own program. This intelligence was proven wrong after the end of World War II. ³ However, the United States also learned after World War II that Japan had acquired a BW program in the late 1930s. From the start, the U.S. BW program included both offensive and defensive components; Secretary of War Henry Stimson argued that a strong BW defense required the United States to possess the means to retaliate in kind. ⁴

The BW program was originally organized under the War Research Service (WRS) as a committee affiliated with the Federal Security Agency. ⁵ George Merck, president of the pharmaceutical company Merck & Co., was appointed head of WRS and thus oversaw the whole program. ⁶ In January 1944 the WRS was abolished, and the CWS took over all BW-related research and production, while the War Department’s Army Surgeon General was made responsible for defensive measures.

A September 1945 memo to the Secretary of War detailed the program’s accomplishments: the United States had used pilot plants to mass produce, among other pathogens, Bacillus anthracis (anthrax) and Brucella melitensis (brucellosis); had developed and field tested a new cluster bomb; and had constructed facilities for the large-scale production of several pathogens, including anti-crop agents. ⁷ BW-related R&D largely took place at Camp (later Fort) Detrick in Maryland under the leadership of George Merck. Pathogens that were weaponized at Detrick were transported to the Dugway Proving Grounds in Utah where open-air testing of biological weapons was conducted. Biological weapons, such as bomblets, bombs, and spray systems that were realistically open-air tested and found to be effective and reliable were produced in large numbers at manufacturing plants located at the Pine Bluff Arsenal in Arkansas. The U.S. invested more than $40,000,000 in these facilities and equipment between 1942 and March 1945. ⁸ By the end of the war, approximately 4,000 people were involved in the program. ⁹

Following a brief lull immediately after World War II, the United States ramped up efforts to develop and manufacture biological weapons as the Cold War expanded. This included extensive new investments in research and production facilities, new laboratory construction at Fort Detrick, a large production plant at Pine Bluff Arsenal, and new production equipment for anti-personnel BW cluster bombs. ¹⁰ This expansion also coincided with a more offensively oriented BW strategy, as the U.S. military abandoned its retaliation-only policy.

After World War II, the United States used research obtained from Japan’s infamous biological warfare program, Unit 731, to support its efforts. American forces interviewed Japanese servicemen involved with the program after the war and discovered Japan’s widespread use during the war of pathogens to spread plague, anthrax, and other diseases throughout the Chinese military and civilian population. ¹¹ In addition, Unit 731 had deliberately infected prisoners of war with deadly pathogens and dispersed BW agents throughout China. ¹² In exchange for Unit 731’s data, the United States granted immunity from prosecution to many of the unit’s researchers and physicians. ¹³

In the 1950s and 1960s, the U.S. BW program developed a wide range of biological weapons that utilized toxins such as botulinum and enterotoxin B; anti-crop pathogens such as wheat rust; non-lethal, incapacitating pathogens such as Coxiella burnetii (Q-fever) and Venezuelan equine encephalitis virus; and lethal, anti-personnel pathogens such as Bacillus anthracis (anthrax). ¹⁴ The United States is not known to have weaponized several of the most lethal BW agents, such as Yersinia pestis (bubonic plague), variola virus (smallpox), and Marburg virus. ¹⁵

During the Korean War, China and North Korea accused the United States of using a wide variety of biological weapons agents, including pathogens that cause smallpox, plague, cholera, and other diseases, but no objective investigation was made to verify these allegations. ¹⁶ The World Peace Council, an organization founded by the Communist Party of the Soviet Union in 1948, organized the International Scientific Commission, which visited North Korea in 1952 and there, among others, interviewed captured American pilots who “confessed” to having released biological weapons over North Korea. The Commission alleged that on fifty occasions, the United States had used biological weapons in North Korea. ¹⁷ Subsequent analysis of documents recovered from Soviet archives by U.S. scholar Milton Leitenberg concluded that the allegations were an orchestrated propaganda plot by the Chinese government, so the findings of the World Peace Council were completely disproven. ¹⁸

Other apparently spurious accusations of U.S. biological weapons began in the 1960s. Since 1962, the Cuban government has leveled eleven accusations against the United States of using biological weapons against its human, animal, and plant populations. ¹⁹ These accusations have included spreading Newcastle disease against the Cuban poultry industry in 1962; introducing the tobacco blue mold disease that devastated Cuba’s tobacco crop in 1979 and 1980; and introducing the insect pest Thrips palmi in 1996. ²⁰ In the Thrips palmi case, the Cuban government invoked Article V of the BTWC to request the convening of a consultative meeting, at which time State parties would hear Cuba’s allegation and the rebuttal by the United States. ²¹ At this meeting the Cuban government provided no scientific information to support its allegations, and since strong alternative explanations were presented concerning why the Thrips insect had invaded Cuba, it was the sense of the majority of representatives at the meeting that Cuba’s allegations were politically motivated. ²²

In 1961 the United States initiated Project 112 whose objectives were to examine the strategic impact of both chemical and biological weapons. ²³ Project 112 found that both chemical and biological weapons should be seen as a part of a broader strategy of “gradual deterrence” in which chemical or biological attacks serve as intermediary steps to deter the Soviet Union from aggression against Europe without resorting to nuclear weapons. ²⁴ Project 112 oversaw and orchestrated extensive new testing of biological and chemical weapons over land and using barges in far off areas of the Pacific Ocean. ²⁵ Project 112 conducted at least fifty open-air trials from December 1962 to 1970. ²⁶ (The sea trials, referred to as Shipboard Hazard and Defense (SHAD), generated controversy in later years, when former Navy personnel alleged that the tests had had a strong negative impact on their health.) ²⁷ These efforts built on earlier tests such as Operation Large Area Coverage (1957-1958) that attempted to understand how air masses could spread biological agents over large areas. ²⁸

On 30 April 1969 President Richard Nixon’s Secretary of Defense, Melvin R. Laird, launched a review of American biological and chemical weapons policies and programs. The review was spurred by public and congressional pressure over the U.S. chemical weapons program, which was perceived as being closely linked to biological weapons. In March 1998, over 6,000 sheep in Utah were killed after a cloud of VX gas drifted off the testing range at the Dugway Proving Grounds. ²⁹ This event was heavily publicized by a documentary about the U.S. chemical and biological weapons program on NBC’s “First Tuesday” TV show, which precipitated major public and congressional backlash. ³⁰ There was also extensive concern over revelations that the United States military had been dumping old chemical weapons from World War II at sea under Operation CHASE (Cut Holes and Sink ‘Em). ³¹

Focusing on the BW program, Laird’s policy review process generated differences of opinion among the relevant agencies; on the one hand, the President’s Scientific Advisory Committee (PSAC) advocated that the United States should retain a solely defensive BW program, as it viewed biological weapons as unreliable and useless. ³² This view was echoed by the United States Department of State, which supported biological disarmament. On the other hand, the military, as represented by the Joint Chiefs of Staff, disagreed, viewing biological weapons as both reliable and an important part of overall strategic deterrence. ³³ These views were submitted to President Nixon along with Laird’s recommendation favoring biological disarmament.

On 25 November 1969 President Nixon announced his decision to abolish all offensive BW capabilities but to retain a defensive program. ³⁴ Before the policy was officially announced, the Department of Defense was ordered to halt all production of biological weapons and to destroy existing stockpiles. Nixon’s decision to dismantle stemmed from several considerations. First, Nixon was convinced that biological weapons had little tactical utility, and were not an effective strategic deterrent, especially when compared to nuclear weapons. ³⁵ Second, Nixon hoped to generate positive publicity to deflect criticism of the U.S. use of tear gas and herbicides such as Agent Orange in Vietnam. Third, in unilaterally giving up biological weapons, Nixon hoped to encourage other countries to do the same.

Destruction of the biological weapons stockpiles took place at Pine Bluff Arsenal in Arkansas, the primary production facility. ³⁶ Experts from the Army; the Departments of Health, Education, and Welfare; the Environmental Protection Agency; and state and local officials were consulted to evaluate all aspects of the plans, including the environmental impact. The destruction of BW agents was successfully completed in May 1972. ³⁷

Immediately following the decision to dismantle the BW program, a bureaucratic debate ensued over how to address toxins, owing in part to the question of whether toxins should be considered chemical or biological weapons. The Department of Defense viewed toxins as chemical weapons that should not be banned. Furthermore, the military believed that toxins offered advantages over other chemical weapons because of their high potency per unit weight and their multivarious effects. ³⁸ By contrast, the Department of State viewed toxins as biological weapons since the toxins in question, botulinum toxin and staphylococcal enterotoxin B, are both derived from bacteria using equipment similar to that used for creating Bacillus anthracis spores. ³⁹ This debate touched off another policy review process, eventually resulting in President Nixon deciding to terminate all offensive-directed development of toxins, but to permit purely defensive research and development.

On March 26, 1975, the United States ratified the BTWC. ⁴⁰ Ratification of the BTWC ensured a stronger institutional basis for long-term U.S. commitment to disarmament.

During the 1980s, the United States played an important role in investigating allegations that the Soviet Union had provided mycotoxins to its communist allies in Vietnam and Laos. ⁴¹ In particular, reports emerged in the late 1970s of widespread toxin attacks on Hmong villages in Southeast Asia. The Hmong are an ethnic group who allied with the United States during the Vietnam War, and so these attacks were believed to originate with the Soviet Union or its allies. Most of the reports described aircraft dispersing yellow material over targeted villages, causing severe illness, often leading to death, among inhabitants. Since the material usually resembled solid yellow dots, the local people named it “Yellow Rain.” ⁴² The United States initiated an investigation into the Yellow Rain incidents through chemical analysis of the substance, and interviews of the Hmong people. The investigation led the United States to conclude that the Soviet Union had developed a biological toxin derived from fungi as a weapons agent, and had provided the toxin to its allies in North Vietnam. ⁴³ The Soviet Union denied U.S. allegations. On the request of the United States, the United Nations conducted two field investigations of Yellow Rain in 1982 and 1983, but both reported inconclusive findings. ⁴⁴

In 1985 the United States became a participant of the Australia Group, whose initial objective was to develop robust export controls on dual-use chemical warfare material. In the early 1990s, the Australia Group expanded its scope to include dual-use biological warfare material. ⁴⁵ However, prior to the Australia Group’s expanded mandate, U.S. suppliers exported to Iraq various bacterial cultures, including Bacillus anthracis and Clostridium botulinum (botulism) between 1985 and 1989. ⁴⁶ At the time, Iraq was under increasing international condemnation for its widespread use of chemical weapons during the Iran-Iraq war. ⁴⁷

In July 2001, international negotiations for a new Ad Hoc Protocol to strengthen the BTWC collapsed following rejection of the protocol by the United States. ⁴⁸ The protocol sought to remedy a major gap in the treaty by developing methods of verifying BTWC compliance through on-site inspections. ⁴⁹ U.S. concerns were two-fold. First, U.S. negotiators believed the protocol was not strong enough, and that violators would be able to evade the proposed new verification measures. ⁵⁰ Second, on-site inspections presented potential and opportunities for inspectors to steal intellectual property and conduct other industrial espionage on pharmaceutical and biotech companies. To date, no further negotiations on the draft Ad Hoc Protocol have commenced.

The September 11, 2001 terrorist attacks and subsequent (unrelated) anthrax attacks on the United States generated major national concern over the potential for biological terrorism. These fears were intensified by simulations such as Operation Dark Winter, which illustrated preparedness gaps in the U.S. health infrastructure concerning the likely high number of infected patients that a large-scale biological attack could cause, as well as the even larger number of “worried-well” patients (these are healthy people who seek medical attention out of the concern they could be infected). ⁵¹ This sentiment was reflected in President Obama’s May 2010 National Security Strategy, which stated that a biological weapons attack “would endanger the lives of hundreds of thousands of people and have unprecedented economic, societal, and political consequences.” ⁵²

The scope of U.S. biodefense research has led to concerns over potential violations of the BTWC. ⁵³ A 2003 article by Mark Wheelis and Malcolm Dando in the Bulletin of the Atomic Scientists argued that some activities by the United States suggest the possible existence of secret, offensive-oriented programs organized under the guise of biodefense. ⁵⁴ Specifically, the authors point to revelations that the Central Intelligence Agency (CIA) had built and tested a biological cluster bomb modeled on a Soviet design, and that the Defense Threat Reduction Agency had tested the ability of non-state actors to develop biological weapons by building a facility to develop, dry, and weaponize non-pathogenic bacterial spores as programs that might violate the BTWC. ⁵⁵ Gregory Koblentz has also cited as problematic projects that have sought to assess the threat of biological weapons to the United States through scientific means by exploring the possibly for genetically engineered biological agents. ⁵⁶ Despite being defensive in intention, other states have used the non-transparency surrounding these projects as a political shield against increasing their own programs’ transparency. ⁵⁷ Specifically, the Russian Ministry of Foreign Affairs has responded to U.S. allegations of Russian non-compliance with the BTWC by pointing to the high number of U.S. biosafety level 3 labs, many of which conduct research on controlled pathogens in potential violation of the BTWC. ⁵⁸

One of the major components of the post 9-11 defenses against bioterrorism is the BioWatch program. Under BioWatch, specialized air samplers employing existing Environmental Protection Agency filters have been installed in 33 major cities around the United States. ⁵⁹ Filters from these samplers are collected every 24 hours and sent to state and local laboratories for analysis that aims to detect the presence of any airborne biological weapons agent. By quickly detecting and identifying a biological weapons attack, public health officials hope to mitigate its effects by quickly quarantining infected individuals and shutting down transportation systems. However, there has been controversy over the program due to the frequency of false positives and its high costs. Between 2003 and 2011, BioWatch had 56 false alarms, leading to decreased public faith in the program. ⁶⁰ The new Generation-3 system that is meant to improve on its predecessor’s failings will cost $3.1 billion over its first five years. ⁶¹

Despite controversies over the BTWC and U.S. biodefense programs, the United States has played a key role in furthering global norms against the proliferation of biological weapons. Since the dissolution of the Soviet Union in December 1992, the United States has sought to support research conducted by former Soviet biological weapons scientists to help ensure that they remain in Russia and do not share their knowledge with would-be proliferators. ⁶² The United States has also worked to develop new global standards for interdicting illicit trafficking of WMD materials, including material for biological weapons, through the creation of the Proliferation Security Initiative (PSI) on 31 May 2003. ⁶³ By September 2003, PSI included 15 countries, and by May 2013 PSI comprised the United States, Poland, and 70 partner states. ⁶⁴ Beginning in 2005, the United States played an active role in dismantling the remnants of the Soviet biological weapons program by instituting the Cooperative Threat Reduction (CTR) program that aimed to secure former Soviet BW facilities and employ their scientists in peacefully-directed R&D. Due to opposition by the Putin administration, the CTR program, including its biological weapons dimensions, ended in 2012 following disagreement over the terms for its renewal. ⁶⁵

As the largest contributor to the G8 Global Partnership against the Spread of Weapons and Materials of Mass Destruction since 2002, the United States has played an important role in furthering the Partnership’s goals to improve biosecurity, prevent illicit trafficking of WMD materials, and further international nonproliferation cooperation. ⁶⁶ The United States also co-sponsored United Nations Security Council Resolution 1540 to prevent states from supporting non-state actors in developing WMD, including biological weapons. ⁶⁷ The resolution was adopted on 28 April 2004, and its efforts remain ongoing.