RESEARCH STARTER

Biological weapons

Biological weapons are pathogenic organisms or toxins used intentionally to harm or kill humans, animals, or plants, often as a means of warfare or terrorism. The historical use of biological weapons dates back thousands of years, with ancient civilizations employing diseases to weaken enemies, such as the Assyrians poisoning wells and the Romans catapulting diseased animals into enemy camps. Significant events in this history include the Tatar siege of Kaffa, where cadavers infected with the bubonic plague were used as a weapon, contributing to the spread of the Black Death in Europe.

In the 20th century, advancements in genetics and biotechnology raised concerns about the potential for creating more lethal biological weapons. Although treaties like the Geneva Protocol and the Biological and Toxin Weapons Convention aimed to prohibit such practices, the lack of a robust inspection system has led to ongoing worries about the proliferation of biological agents. Recent events have shown that the line between legitimate research and bioweapons development can blur, highlighting the dangers posed by both state and non-state actors.

As scientists continue to explore genetic manipulation, the potential for both beneficial medical advancements and harmful applications remains a critical concern. The hope is that with responsible governance and international collaboration, the promise of biotechnology can be harnessed for peace rather than harm.

Full Article

SIGNIFICANCE: Just as twentieth-century discoveries in chemistry and physics led to such devastating weapons as poison gases and nuclear bombs, so humanity in the twenty-first century faces the prospect that the biotechnological revolution will lead to the development and use of extremely deadly biological weapons.

Early History

Biological warfare antedates by several centuries the discovery of the gene. Just as the history of genetics did not begin with Gregor Mendel, whose pea-plant experiments eventually helped found modern genetics, the history of biological warfare began long before the Japanese dropped germ-filled bombs on several Chinese cities during World War II. For example, the Assyrians, six centuries before the common era, knew enough about rye ergot, a fungus disease, to poison their enemies’ wells. The ancient Greeks also used disease as a military weapon, and the Romans catapulted diseased animals into enemy camps. A famous medieval use of biological weapons occurred during the Tatar siege of Kaffa, a fortified Black Sea port, then held by Christian Genoans. When Tatars started dying of the bubonic plague, the survivors catapulted cadavers into the walled city. Many Genoans consequently died of the plague, and the remnant who sailed back to Italy contributed to the spread of the Black Death into Europe.

Once smallpox was recognized as a highly contagious disease, military men made use of it in war. For example, the conquistador Francisco Pizarro presented South American natives with smallpox-contaminated clothing, and, in an early case of ethnic cleansing, the British and Americans used deliberately induced smallpox epidemics to eliminate native tribes from desirable land.

As scientists in the nineteenth and twentieth centuries learned more about the nature and modes of reproduction of such diseases as anthrax and smallpox, germ warfare began to become part of such discussions as the First International Peace Conference in The Hague (1899). The worldwide revulsion against the chemical weapons used in World War I, along with a concern that biological weapons would be more horrendous, led to the Geneva Protocol (1925), which prohibited the first use of germ weapons, but not their development.

From Germ Warfare to Genetic Weapons

With the accelerating knowledge about the genetics of various disease-causing microorganisms, several countries became concerned with the threat to their security posed by the weaponization of these pathogens. Although several states signed the Geneva Protocol in the late 1920s, others signed only after assurances of their right to retaliate. The United States, which did not ratify the treaty until 1975, did extensive research on germ weapons during the 1950s and 1960s. American scientists were able to make dry infectious agents that could be packed into shells and bombs, and estimates were made that ten airplanes with such bombs could kill or seriously disable tens of millions of people. Unknown to Congress and the American people, tests using apparently harmless microbes were performed on such large communities as San Francisco. When news of these secret tests was made public, many questioned their morality. Extensive criticism of the research and development of these weapons, together with the realization that these weapons posed a threat to the attackers as well as the attacked, led President Richard Nixon to end the American biological weapons program formally in 1969.

Abhorrence of biological weapons extended to the world community, and the Biological and Toxin Weapons Convention (BTWC), also called the Biological Weapons Convention (BWC)—a treaty that prohibited the development, production, and stockpiling of bacteriological weapons—was signed in Washington, DC, London, and Moscow in 1972 and was put into force in 1975. Although it was eventually signed by most members of the United Nations (189 states parties by 2026), the nations that signed the pact failed to reach an agreement on an inspection system that would control the proliferation of these weapons. In 2022, the BWC’s Ninth Review Conference adopted a final document that launched a new expert-led process aimed at strengthening the Convention. A pivotal irony of the BTWC is that while most of the world was renouncing germ warfare, biologists were learning how to manipulate DNA, the molecule that carries genetic information, in powerful new ways. This knowledge made possible the creation of “superbugs,” infectious agents for which there are no cures.

Some scientists warned the public and international agencies about these new germ weapons. Other investigators discovered that American researchers were creating infectious agents that would confuse diagnosticians and defeat vaccines. Similarly, Soviet researchers on an island in the Aral Sea, described as the world’s largest biological weapons test site, were producing germ weapons that could be loaded on missiles. When Boris Yeltsin became president of Russia, he discovered that the secret police and military officials had misinformed him about these programs, in which deadly accidents had occurred. Also troubling was the spread of biological agents to such countries as Iraq. American and French companies legally shipped anthrax and botulinum bacteria to Iraq, whose scientists later acknowledged that they had used these microbes to make tons of biological weapons during the 1980s.

With the demise of the Soviet Union and increasing violence in the Balkans and the Middle East, politicians became fearful that experts who had dedicated their careers to making biological weapons would sell their knowledge to rogue nations or terrorist groups. Indeed, deadly pathogens were part of world trade, since the line separating legitimate and illegitimate research, defensive and offensive biological weapons, was fuzzy. In the 1980s, members of a religious cult spread salmonella, a disease-causing bacterium, in an Oregon town, causing more than seven hundred people to become very ill. The same company that sold salmonella to this religious cult also sold pathogens to the University of Baghdad. Bioterrorism had become both a reality and a threat.

The Future of Genetic Weapons

Some scientists and politicians have posited that a nation’s best defense against bioterrorism is advanced genetic knowledge so that scientists can tailor vaccines to respond to traditional and new biological weapons. For example, the Human Genome Project, which succeeded in mapping the human genetic material, has the potential for revealing both the vulnerabilities and defenses of the immune system. (The human genome sequence contains about 3.2 billion bases and approximately 20,000 protein-coding genes. These data are available online in a variety of formats.) On the other hand, such knowledge could prove dangerous if bioengineered microbes could target the genetic vulnerabilities of certain ethnic groups. Some scientists have found these speculations about genocidal biological weapons unevidenced and unsubstantial. Other scientists pointed out that dramatic genetic differences between ethnic groups are a reality. Believers in ethnic biological weapons point to existing techniques for selectively killing certain cells and for inactivating certain DNA sequences. These techniques, developed with the hope of curing genetic diseases, could also be used to cause harm. Knowledge of the structure of the human genome will increasingly lead to an understanding of its function, and this knowledge will make it possible to manipulate these information-laden molecules in both benign and malign ways. Modern biotechnology thus presents humanity with a great promise, to better health and life in peace, and a great peril, to multiply sickness and death in war. Many scientists, politicians, and ordinary people hope that humanity will choose the path of promise.

The origin of the COVID-19 pandemic became a contentious topic, with debates over whether the virus emerged naturally or resulted from a laboratory incident in China’s Wuhan Institute of Virology. These allegations were not confirmed, but they highlighted the potential devastation of biological weapons. This concern sparked conversations about biosecurity and the dual-use nature of biological research facilities. Additionally, the proliferation of gene-editing technologies, such as Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), lowered the barriers to developing sophisticated biological agents. Some experts called for enhanced transparency to ensure compliance with international treaties like the BWC.

Key terms

  • Anthrax: an acute bacterial disease that affects animals and humans and that is especially deadly in its pulmonary form
  • Biological weapon: the military or terrorist use of such organisms as bacteria and viruses to cause disease and death in people, animals, or plants
  • Bioterrorist: an individual or group that coercively threatens or uses biological weapons, often for ideological reasons
  • Ethnic weapons: genetic weapons that target certain racial groups
  • Genetic engineering: the use of recombinant DNA to alter the genetic material in an organism
  • Immune system: the biological defense mechanism that protects the body from disease-causing microorganisms
  • Recombinant DNA: DNA prepared by transplanting and splicing genes from one species into the cells of another species
  • Smallpox: an acute, highly infectious, often fatal disease characterized by fever followed by the eruption of pustules

Bibliography

Alibeck, Ken, with Stephen Handelman. Biohazard: The Chilling True Story of the Largest Covert Biological Weapons Program in the World, Told from the inside by the Man Who Ran It. Delta, 2014.

Bentley, Michelle. The Biological Weapons Taboo. Oxford UP, 2024.

“Biological Weapons Convention.” United Nations Office for Disarmament Affairs, disarmament.unoda.org/en/our-work/weapons-mass-destruction/biological-weapons/biological-weapons-convention. Accessed 11 May 2026.

“Biological Weapons.” The World Health Organization, www.who.int/health-topics/biological-weapons. Accessed 11 May 2026.

Blokdyk, Gerardus. Biological Weapons A Complete Guide - 2024 Edition. Emereo Publishing, 2023.

British Medical Association. Biotechnology, Weapons, and Humanity. Harwood, 1999.

Cole, Leonard A. The Eleventh Plague: The Politics of Biological and Chemical Warfare. Freeman, 1996.

Croddy, Eric. Chemical and Biological Warfare: A Comprehensive Survey for the Concerned Citizen. Copernicus, 2002.

Cross, Glenn. “Biological Weapons in the ‘Shadow War.’” War on the Rocks, 9 Nov. 2021, warontherocks.com/biological-weapons-in-the-shadow-war/. Accessed 11 May 2026.

“Gene.” National Human Genome Research Institute, 12 May 2026, www.genome.gov/genetics-glossary/Gene. Accessed 11 May 2026.

Gerstein, Daniel M. National Security and Arms Control in the Age of Biotechnology: The Biological and Toxin Weapons Convention. Rowman, 2013.

Guillemin, Jeanne. Biological Weapons: From the Invention of State-Sponsored Programs to Contemporary Bioterrorism. Columbia UP, 2005

“The Havoc Wrought by COVID-19 Will Spark New Concern over Bioweapons.” The Economist, 23 Apr. 2020, www.economist.com/united-states/2020/04/23/the-havoc-wrought-by-covid-19-will-spark-new-concern-over-bio-weapons?. Accessed 11 May. 2026.

Lutwick, Larry I., and Suzanne M. Lutwick, editors. Beyond Anthrax: The Weaponization of Infectious Diseases. Springer, 2009.

Miller, Judith, et al. Germs: Biological Weapons and America’s Secret War. Simon, 2012.

Paris, Katherine. Genome Editing and Biological Weapons: Assessing the Risk of Misuse. Springer, 2023.

Piller, Charles, and Keith R. Yamamoto. Gene Wars: Military Control over the New Genetic Technologies. Morrow, 1988.

Rhodes, John. The End of Plagues: The Global Battle against Infectious Disease. Palgrave, 2013.

Smith, Frank L. American Biodefense: How Dangerous Ideas about biological Weapons Shape National Security. Cornell UP, 2014.

Southwick, Frederick S. Infectious Diseases: A Clinical Short Course. 4th ed., McGraw, 2020.

United States Mission to International Organizations in Geneva. “The Ninth Biological Weapons Convention Review Conference.” 21 Dec. 2022, geneva.usmission.gov/2022/12/21/the-ninth-biological-weapons-convention-review-conference/. Accessed 11 May 2026.

Full Article

SIGNIFICANCE: Just as twentieth-century discoveries in chemistry and physics led to such devastating weapons as poison gases and nuclear bombs, so humanity in the twenty-first century faces the prospect that the biotechnological revolution will lead to the development and use of extremely deadly biological weapons.

Early History

Biological warfare antedates by several centuries the discovery of the gene. Just as the history of genetics did not begin with Gregor Mendel, whose pea-plant experiments eventually helped found modern genetics, the history of biological warfare began long before the Japanese dropped germ-filled bombs on several Chinese cities during World War II. For example, the Assyrians, six centuries before the common era, knew enough about rye ergot, a fungus disease, to poison their enemies’ wells. The ancient Greeks also used disease as a military weapon, and the Romans catapulted diseased animals into enemy camps. A famous medieval use of biological weapons occurred during the Tatar siege of Kaffa, a fortified Black Sea port, then held by Christian Genoans. When Tatars started dying of the bubonic plague, the survivors catapulted cadavers into the walled city. Many Genoans consequently died of the plague, and the remnant who sailed back to Italy contributed to the spread of the Black Death into Europe.

Once smallpox was recognized as a highly contagious disease, military men made use of it in war. For example, the conquistador Francisco Pizarro presented South American natives with smallpox-contaminated clothing, and, in an early case of ethnic cleansing, the British and Americans used deliberately induced smallpox epidemics to eliminate native tribes from desirable land.

As scientists in the nineteenth and twentieth centuries learned more about the nature and modes of reproduction of such diseases as anthrax and smallpox, germ warfare began to become part of such discussions as the First International Peace Conference in The Hague (1899). The worldwide revulsion against the chemical weapons used in World War I, along with a concern that biological weapons would be more horrendous, led to the Geneva Protocol (1925), which prohibited the first use of germ weapons, but not their development.

From Germ Warfare to Genetic Weapons

With the accelerating knowledge about the genetics of various disease-causing microorganisms, several countries became concerned with the threat to their security posed by the weaponization of these pathogens. Although several states signed the Geneva Protocol in the late 1920s, others signed only after assurances of their right to retaliate. The United States, which did not ratify the treaty until 1975, did extensive research on germ weapons during the 1950s and 1960s. American scientists were able to make dry infectious agents that could be packed into shells and bombs, and estimates were made that ten airplanes with such bombs could kill or seriously disable tens of millions of people. Unknown to Congress and the American people, tests using apparently harmless microbes were performed on such large communities as San Francisco. When news of these secret tests was made public, many questioned their morality. Extensive criticism of the research and development of these weapons, together with the realization that these weapons posed a threat to the attackers as well as the attacked, led President Richard Nixon to end the American biological weapons program formally in 1969.

Abhorrence of biological weapons extended to the world community, and the Biological and Toxin Weapons Convention (BTWC), also called the Biological Weapons Convention (BWC)—a treaty that prohibited the development, production, and stockpiling of bacteriological weapons—was signed in Washington, DC, London, and Moscow in 1972 and was put into force in 1975. Although it was eventually signed by most members of the United Nations (189 states parties by 2026), the nations that signed the pact failed to reach an agreement on an inspection system that would control the proliferation of these weapons. In 2022, the BWC’s Ninth Review Conference adopted a final document that launched a new expert-led process aimed at strengthening the Convention. A pivotal irony of the BTWC is that while most of the world was renouncing germ warfare, biologists were learning how to manipulate DNA, the molecule that carries genetic information, in powerful new ways. This knowledge made possible the creation of “superbugs,” infectious agents for which there are no cures.

Some scientists warned the public and international agencies about these new germ weapons. Other investigators discovered that American researchers were creating infectious agents that would confuse diagnosticians and defeat vaccines. Similarly, Soviet researchers on an island in the Aral Sea, described as the world’s largest biological weapons test site, were producing germ weapons that could be loaded on missiles. When Boris Yeltsin became president of Russia, he discovered that the secret police and military officials had misinformed him about these programs, in which deadly accidents had occurred. Also troubling was the spread of biological agents to such countries as Iraq. American and French companies legally shipped anthrax and botulinum bacteria to Iraq, whose scientists later acknowledged that they had used these microbes to make tons of biological weapons during the 1980s.

With the demise of the Soviet Union and increasing violence in the Balkans and the Middle East, politicians became fearful that experts who had dedicated their careers to making biological weapons would sell their knowledge to rogue nations or terrorist groups. Indeed, deadly pathogens were part of world trade, since the line separating legitimate and illegitimate research, defensive and offensive biological weapons, was fuzzy. In the 1980s, members of a religious cult spread salmonella, a disease-causing bacterium, in an Oregon town, causing more than seven hundred people to become very ill. The same company that sold salmonella to this religious cult also sold pathogens to the University of Baghdad. Bioterrorism had become both a reality and a threat.

The Future of Genetic Weapons

Some scientists and politicians have posited that a nation’s best defense against bioterrorism is advanced genetic knowledge so that scientists can tailor vaccines to respond to traditional and new biological weapons. For example, the Human Genome Project, which succeeded in mapping the human genetic material, has the potential for revealing both the vulnerabilities and defenses of the immune system. (The human genome sequence contains about 3.2 billion bases and approximately 20,000 protein-coding genes. These data are available online in a variety of formats.) On the other hand, such knowledge could prove dangerous if bioengineered microbes could target the genetic vulnerabilities of certain ethnic groups. Some scientists have found these speculations about genocidal biological weapons unevidenced and unsubstantial. Other scientists pointed out that dramatic genetic differences between ethnic groups are a reality. Believers in ethnic biological weapons point to existing techniques for selectively killing certain cells and for inactivating certain DNA sequences. These techniques, developed with the hope of curing genetic diseases, could also be used to cause harm. Knowledge of the structure of the human genome will increasingly lead to an understanding of its function, and this knowledge will make it possible to manipulate these information-laden molecules in both benign and malign ways. Modern biotechnology thus presents humanity with a great promise, to better health and life in peace, and a great peril, to multiply sickness and death in war. Many scientists, politicians, and ordinary people hope that humanity will choose the path of promise.

The origin of the COVID-19 pandemic became a contentious topic, with debates over whether the virus emerged naturally or resulted from a laboratory incident in China’s Wuhan Institute of Virology. These allegations were not confirmed, but they highlighted the potential devastation of biological weapons. This concern sparked conversations about biosecurity and the dual-use nature of biological research facilities. Additionally, the proliferation of gene-editing technologies, such as Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), lowered the barriers to developing sophisticated biological agents. Some experts called for enhanced transparency to ensure compliance with international treaties like the BWC.

Key terms

  • Anthrax: an acute bacterial disease that affects animals and humans and that is especially deadly in its pulmonary form
  • Biological weapon: the military or terrorist use of such organisms as bacteria and viruses to cause disease and death in people, animals, or plants
  • Bioterrorist: an individual or group that coercively threatens or uses biological weapons, often for ideological reasons
  • Ethnic weapons: genetic weapons that target certain racial groups
  • Genetic engineering: the use of recombinant DNA to alter the genetic material in an organism
  • Immune system: the biological defense mechanism that protects the body from disease-causing microorganisms
  • Recombinant DNA: DNA prepared by transplanting and splicing genes from one species into the cells of another species
  • Smallpox: an acute, highly infectious, often fatal disease characterized by fever followed by the eruption of pustules

Bibliography

Alibeck, Ken, with Stephen Handelman. Biohazard: The Chilling True Story of the Largest Covert Biological Weapons Program in the World, Told from the inside by the Man Who Ran It. Delta, 2014.

Bentley, Michelle. The Biological Weapons Taboo. Oxford UP, 2024.

“Biological Weapons Convention.” United Nations Office for Disarmament Affairs, disarmament.unoda.org/en/our-work/weapons-mass-destruction/biological-weapons/biological-weapons-convention. Accessed 11 May 2026.

“Biological Weapons.” The World Health Organization, www.who.int/health-topics/biological-weapons. Accessed 11 May 2026.

Blokdyk, Gerardus. Biological Weapons A Complete Guide - 2024 Edition. Emereo Publishing, 2023.

British Medical Association. Biotechnology, Weapons, and Humanity. Harwood, 1999.

Cole, Leonard A. The Eleventh Plague: The Politics of Biological and Chemical Warfare. Freeman, 1996.

Croddy, Eric. Chemical and Biological Warfare: A Comprehensive Survey for the Concerned Citizen. Copernicus, 2002.

Cross, Glenn. “Biological Weapons in the ‘Shadow War.’” War on the Rocks, 9 Nov. 2021, warontherocks.com/biological-weapons-in-the-shadow-war/. Accessed 11 May 2026.

“Gene.” National Human Genome Research Institute, 12 May 2026, www.genome.gov/genetics-glossary/Gene. Accessed 11 May 2026.

Gerstein, Daniel M. National Security and Arms Control in the Age of Biotechnology: The Biological and Toxin Weapons Convention. Rowman, 2013.

Guillemin, Jeanne. Biological Weapons: From the Invention of State-Sponsored Programs to Contemporary Bioterrorism. Columbia UP, 2005

“The Havoc Wrought by COVID-19 Will Spark New Concern over Bioweapons.” The Economist, 23 Apr. 2020, www.economist.com/united-states/2020/04/23/the-havoc-wrought-by-covid-19-will-spark-new-concern-over-bio-weapons?. Accessed 11 May. 2026.

Lutwick, Larry I., and Suzanne M. Lutwick, editors. Beyond Anthrax: The Weaponization of Infectious Diseases. Springer, 2009.

Miller, Judith, et al. Germs: Biological Weapons and America’s Secret War. Simon, 2012.

Paris, Katherine. Genome Editing and Biological Weapons: Assessing the Risk of Misuse. Springer, 2023.

Piller, Charles, and Keith R. Yamamoto. Gene Wars: Military Control over the New Genetic Technologies. Morrow, 1988.

Rhodes, John. The End of Plagues: The Global Battle against Infectious Disease. Palgrave, 2013.

Smith, Frank L. American Biodefense: How Dangerous Ideas about biological Weapons Shape National Security. Cornell UP, 2014.

Southwick, Frederick S. Infectious Diseases: A Clinical Short Course. 4th ed., McGraw, 2020.

United States Mission to International Organizations in Geneva. “The Ninth Biological Weapons Convention Review Conference.” 21 Dec. 2022, geneva.usmission.gov/2022/12/21/the-ninth-biological-weapons-convention-review-conference/. Accessed 11 May 2026.

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