Timeline of lab leaks

This is a timeline of lab leaks, documenting notable laboratory-acquired infections, confirmed and suspected laboratory leaks, biosafety failures, research controversies, and policy responses related to the handling of dangerous pathogens. It spans from the early twentieth century to the present and includes both well-documented incidents and debated hypotheses. The timeline aims to provide historical context on how laboratory risks have evolved, how biosafety standards have emerged, and how scientific, governmental, and international institutions respond to accidents, controversies, and ongoing uncertainties in high-risk biological research.

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Year (Month and date)	Event type	Details	Country (location)
1900s	Laboratory-acquired infection	Early plague research leads to laboratory infections among scientists studying *Yersinia pestis*, underscoring the dangers of aerosol exposure before modern containment standards.	India; France
1903		A young, previously healthy assistant bacteriologist becomes infected with glanders after accidental laboratory exposure while handling material from two fatal human cases. The infection is traced to occupational contact during bacteriological work, indicating direct laboratory origin. The case demonstrates that routine handling of pathogenic samples, in the absence of effective biosafety controls, can result in severe human disease. It provides early documented evidence of laboratory-acquired infection involving a highly dangerous zoonotic pathogen.
1918–1920	Laboratory research controversy	Influenza virus samples from the 1918 pandemic are later preserved and studied under laboratory conditions, raising long-term biosafety concerns regarding pathogen retention.	Global
1930	Laboratory-acquired infection	Psittacosis outbreaks affect laboratory and animal-handling staff studying avian pathogens, contributing to recognition of airborne transmission risks.	United States; Europe
1930s	Laboratory-acquired infections	Early bacteriology laboratories report frequent infections among researchers working with tuberculosis, plague, and brucellosis, illustrating the absence of standardized containment practices.	Global
1936	Laboratory-acquired infection	Q fever infections occur among laboratory workers handling *Coxiella burnetii*, contributing to recognition of extreme infectivity via aerosols.	Australia; United States
1941	Laboratory accident	Accidental infections occur among personnel handling *Coccidioides* spp., leading to early recommendations for respiratory protection in mycology labs.	United States
1940s	Early laboratory accident	Researchers working with Brucella and other zoonotic pathogens experience frequent laboratory-acquired infections, helping establish the modern concept of laboratory biosafety and containment.	United States; United Kingdom
1943	Laboratory accident	U.S. biological research programs experience accidental infections among staff working with anthrax and brucellosis during wartime research expansion.	United States
1949	Laboratory safety incident	A release of radioactive materials from a U.S. government experiment exposes gaps in laboratory containment and monitoring, influencing later biosafety and biosecurity frameworks.	United States
1950s	Laboratory-acquired infections	Multiple cases of smallpox, tularemia, and Q fever occur among laboratory workers, highlighting the risks of inadequate containment in early microbiology research.	Global
1951	Laboratory-acquired infection	Multiple tularemia infections occur among laboratory personnel, reinforcing the need for respirators and controlled airflow in microbiology labs.	United States
1952	Laboratory-acquired infection	Laboratory workers contract hepatitis during blood and serum research, contributing to later adoption of universal precautions in clinical laboratories.	United States
1954	Laboratory-acquired infection	Researchers studying Venezuelan equine encephalitis experience laboratory infections, contributing to recognition of aerosol transmission risks in laboratories.	United States
1957	Laboratory biosafety incident	Influenza research laboratories report accidental exposures during vaccine strain development, highlighting risks in large-scale viral culture.	Global
1959	Laboratory-acquired infection	Poliovirus infections among laboratory workers prompt tighter controls during vaccine research and production.	Global
1962	Laboratory containment concern	Concerns emerge over accidental release risks during large-scale poliovirus production for oral polio vaccines.	Global
1963	Laboratory-acquired infection	Smallpox infections occur among laboratory personnel handling viral samples, reinforcing the need for higher containment levels for orthopoxviruses.	United Kingdom
1964	Laboratory safety incident	Accidental laboratory infections with rabies virus occur during reminder-vaccine research, highlighting risks associated with neurotropic pathogens.	United States
1965	Laboratory safety incident	Accidental exposure to Venezuelan equine encephalitis virus occurs during aerosol studies, reinforcing the need for negative-pressure facilities.	United States
1967 (March)	Confirmed lab leak	Smallpox virus escapes from a laboratory at the Marburg Medical Mission Hospital, infecting a laboratory worker and resulting in secondary cases.	Germany (Marburg)
1967 (August)	Confirmed lab accident	The Marburg virus outbreak originates from laboratory work with infected African green monkeys imported for research, causing severe hemorrhagic fever among laboratory staff.	Germany; Yugoslavia (Belgrade)
1968	Laboratory-acquired infection	Lassa fever virus infects laboratory workers during diagnostic and research activities, emphasizing the need for maximum-containment facilities.	Nigeria; United States
1969	Policy milestone	The United States renounces offensive biological weapons research, partly motivated by risks associated with laboratory handling of dangerous pathogens.	United States
1971 (March)	Laboratory-associated outbreak	A smallpox outbreak in London is linked to laboratory handling of variola virus, reinforcing concerns about urban laboratory siting.	United Kingdom (London)
1971	Laboratory safety reform milestone	The U.S. National Cancer Institute suspends several viral oncology programs following biosafety concerns related to tumor virus research.	United States
1972	Biosafety policy milestone	The Biological Weapons Convention enters into force, restricting biological weapons development and indirectly shaping laboratory biosecurity norms.	Global
1975	Laboratory safety failure	A laboratory-associated smallpox outbreak in India is linked to research handling variola virus prior to global eradication efforts.	India
1976	Laboratory-linked outbreak investigation	The Legionnaires’ disease outbreak leads to scrutiny of laboratory handling of *Legionella* cultures during early investigations.	United States (Philadelphia)
1977	Alleged lab-origin outbreak	The 1977–1978 reemergence of H1N1 influenza shows genetic sequences nearly identical to 1950s strains, making a natural origin unlikely. The outbreak is unusually mild and primarily affects younger populations, consistent with prior immunity in older individuals. Possible explanations include a laboratory accident, a vaccine trial escape, or deliberate release. Although a lab origin is plausible, available evidence does not allow a definitive conclusion. The episode would be frequently cited in gain-of-function debates but would provide limited guidance for modern biosafety policy.	Global (origin disputed)
1978 (April)	Confirmed lab leak	Smallpox virus escapes from the University of Birmingham Medical School, infecting photographer Janet Parker, who later dies; the incident leads to major reforms in laboratory biosafety.	United Kingdom (Birmingham)
1979 (April)	Suspected lab leak	An anthrax outbreak in Sverdlovsk is later attributed to an accidental release from a military microbiology facility, a conclusion officially acknowledged by Russian authorities in 1992.	Soviet Union (Sverdlovsk; now Yekaterinburg, Russia)
1980	Biosafety milestone	Following global eradication of smallpox, remaining variola virus stocks are restricted to two high-security laboratories to reduce accidental release risk.	United States; Soviet Union
1981	Laboratory biosafety reform	The emergence of HIV heightens awareness of laboratory exposure risks and leads to strengthened universal precautions in clinical and research settings.	Global
1983	Laboratory-acquired infection	Rift Valley fever virus infects laboratory staff during diagnostic work, prompting upgrades to animal and vector containment.	Kenya; United States
1984	Laboratory safety incident	A laboratory worker contracts Rift Valley fever virus during research, prompting reviews of mosquito-borne pathogen containment.	United States
1988	Laboratory containment incident	A laboratory worker is exposed to Machupo virus during research activities, underscoring risks associated with arenavirus research.	United States
1989 (November)	Suspected lab-origin outbreak	The Reston ebolavirus emerges in a primate quarantine facility, raising concerns about laboratory and animal-research-related transmission, though no human disease develops.	United States (Virginia)
1990	Laboratory-acquired infection	Laboratory exposure to Crimean–Congo hemorrhagic fever virus leads to infections among medical and research personnel.	Pakistan; South Africa
1991	Laboratory exposure	Accidental exposure to hantavirus occurs during rodent research, illustrating zoonotic risks in laboratory animal facilities.	United States
1992	Official acknowledgment	Russian authorities acknowledge that the 1979 Sverdlovsk anthrax outbreak results from a military laboratory accident, influencing international transparency debates.	Russia
1994	Laboratory-acquired infection	A researcher contracts Sabia virus following laboratory exposure, drawing attention to risks in handling rare hemorrhagic fever viruses.	Brazil
1996	Laboratory accident	A laboratory worker becomes infected with Ebola virus following a needle-stick injury during animal research, surviving after intensive care.	Russia (Moscow)
1997	Laboratory exposure	Accidental exposure to *Burkholderia pseudomallei* (melioidosis) occurs in clinical laboratories, highlighting risks from misidentified pathogens.	Australia
1999	Laboratory safety failure	A laboratory worker dies following exposure to genetically modified adenovirus, intensifying scrutiny of biosafety in gene therapy research.	United States (Pennsylvania)
2001	Laboratory safety review	Reviews of biodefense laboratories intensify following expanded pathogen research programs, emphasizing inventory control and personnel reliability.	United States
2001 (September)	Suspected lab-linked biocrime	Anthrax spores are mailed to U.S. media and government offices; the FBI later attributes the material to a U.S. biodefense laboratory, though debate persists.	United States
2002	Biosafety lapse	Improper handling of West Nile virus samples leads to laboratory infections, prompting reviews of biosafety training and protocols.	United States
2003 (December)	Confirmed lab leaks	SARS-CoV leaks from research laboratories in Singapore and Taiwan due to biosafety failures following the original SARS outbreak.	Singapore; Taiwan
2004 (April)	Confirmed lab leak	A SARS laboratory accident at China’s National Institute of Virology in Beijing infects multiple researchers and causes secondary transmission.	China (Beijing)
2004	Laboratory biosafety review	Global reviews of SARS laboratory incidents lead to strengthened WHO biosafety guidance for coronavirus research.	Global
2005	Laboratory containment lapse	Influenza virus samples are accidentally distributed to laboratories worldwide during proficiency testing, raising concerns about quality control.	Global
2006	Laboratory containment failure	Accidental exposure to live tuberculosis bacteria occurs during laboratory work, highlighting ongoing risks in clinical microbiology laboratories.	Canada
2006	Laboratory-acquired infection	Laboratory workers are infected with vaccinia virus during smallpox vaccine research, prompting updates to vaccination and handling policies.	United States
2007 (August)	Confirmed lab leak	The 2007 United Kingdom foot-and-mouth disease outbreak results from the release of infectious effluent from a laboratory site near Pirbright, Surrey. Leaking waste pipes from animal health laboratories allow the virus to infect four nearby farms, with cases detected through routine surveillance. Investigations identify serious deficiencies in effluent containment systems. The outbreak leads to farm quarantines, animal culling, trade restrictions, and government compensation, prompting laboratory infrastructure upgrades and renewed scrutiny of biosafety and waste management practices.	United Kingdom
2008	Laboratory-acquired infection	Brucellosis infections are reported among laboratory workers due to improper handling of bacterial cultures.	Spain
2009	Biosafety concern	Laboratories handling pandemic H1N1 influenza rapidly scale up work, raising concerns about containment capacity and personnel training under emergency conditions.	Global
2009		A fatal laboratory-acquired infection with Yersinia pestis is reported in Chicago. The case involves a university researcher working with an attenuated pigmentation-negative (pgm-) strain (KIM D27), previously not associated with human fatalities. An investigation by local and federal health authorities concludes that death had likely resulted from unrecognized occupational exposure, leading to septic shock. Postmortem analysis identifies hereditary hemochromatosis, suggesting iron overload may have increased the strain’s virulence.	United States
2010	Laboratory-acquired infection	Q fever infections among laboratory workers trigger revisions to handling protocols for highly infectious intracellular bacteria.	Netherlands
2011	Research controversy	Experiments modifying H5N1 influenza to enhance transmissibility in mammals spark global debate over laboratory risk and dual-use research of concern.	Netherlands; United States
2011	Laboratory infection	A researcher in Taiwan becomes infected with SARS-CoV during laboratory work, leading to temporary suspension and investigation of facilities.	Taiwan
2012	Biosafety controversy	Researchers in the Netherlands and the United States publish studies showing that avian influenza H5N1 can be experimentally altered to transmit through the air between mammals, using ferrets as models. The work, led by Ron Fouchier and Yoshihiro Kawaoka, demonstrates that a highly lethal virus can acquire airborne transmissibility. Publication of the findings triggers global concern over biosafety and dual-use research, intensifies debate on gain-of-function experiments, and prompts temporary moratoria on U.S.-funded studies.	Netherlands; United States
2013	Laboratory oversight issue	High-containment laboratories expand globally, prompting debate over whether increased numbers of BSL-3 and BSL-4 facilities elevate accident risks.	Global
2014 (June–July)	Confirmed lab safety failures	The U.S. CDC reports multiple biosafety incidents, including accidental exposure of workers to live anthrax and improper shipment of live avian influenza virus.	United States (multiple locations)
2014 (July)	Discovery of lab containment failure	Forgotten vials of viable smallpox virus are discovered in an FDA laboratory storage room, prompting renewed scrutiny of pathogen storage practices.	United States (Bethesda, Maryland)
2014	Laboratory safety stand-down	U.S. federal laboratories temporarily halt work with select agents to review biosafety practices after multiple reported incidents.	United States
2014		L’Institut Pasteur faces a serious biosafety and governance problem after discovering that 29 tubes containing 2,349 SARS virus fragments are missing from a laboratory inventory. The loss is detected during routine checks, but inadequate tracking systems prevent recovery or reconstruction of the samples’ whereabouts. Internal and regulatory investigations fail to resolve the issue, prompting legal action. Although the samples are non-infectious, the incident exposes critical weaknesses in laboratory oversight, sample management, and institutional accountability.	France
2015	Biosafety policy response	The U.S. government pauses federal funding for certain gain-of-function research involving influenza, SARS, and MERS viruses due to laboratory risk concerns.	United States
2015		Researchers at the University of North Carolina at Chapel Hill report the discovery of a novel bat SARS-like coronavirus, SHC014-CoV, capable of infecting human cells without prior mutation. Published in Nature Medicine in November 2015, the study shows the virus uses the same receptor as SARS-CoV and replicates efficiently in human lung cells. No existing treatments neutralize it. The finding highlights zoonotic risk from bat coronaviruses and intensifies debate over gain-of-function research restrictions and pandemic preparedness.
2015	Laboratory-acquired infection	Laboratory exposure leads to brucellosis cases among researchers, reinforcing the need for biosafety cabinets and respiratory protection.	United States
2015	Laboratory oversight incident	A biosafety lapse involving live *Bacillus anthracis* samples prompts temporary shutdowns and retraining at U.S. federal laboratories.	United States
2016	Laboratory safety incident	A laboratory worker is potentially exposed to Zika virus during research, prompting internal reviews of vector-borne pathogen handling.	United States
2017	Regulatory action	International scientific bodies emphasize stricter oversight of dual-use life sciences research following repeated laboratory safety incidents.	Global
2017		Scientists in Canada successfully synthesize the extinct horsepox virus in a laboratory using commercially available DNA, demonstrating the feasibility of reconstructing large orthopoxviruses. The work raises major biosecurity concerns because horsepox is closely related to variola, the virus that causes smallpox. Public health experts warn that the research exemplifies dual-use science, where potential benefits such as vaccine development are outweighed by risks of misuse, regulatory gaps, and the possible facilitation of smallpox re-creation.	Canada
2018	Biosafety warning	U.S. diplomatic cables express concern about safety practices at the Wuhan Institute of Virology during visits by embassy officials.	China (Wuhan)
2018	Laboratory compliance action	A major U.S. biodefense laboratory loses access to select agents following repeated safety violations, underscoring enforcement of biosafety regulations.	United States (Fort Detrick, Maryland)
2019	Biosafety governance concern	Calls intensify for international transparency and incident reporting standards for high-risk pathogen laboratories.	Global
2019	Industrial laboratory accident	An accidental release of *Brucella* bacteria from a pharmaceutical facility results in thousands of infections, drawing attention to biosafety beyond research laboratories.	China (Lanzhou)
2019 (November–December)	Disputed origin hypothesis	The origin of the COVID-19 pandemic becomes the subject of global debate, with one hypothesis proposing accidental release from a research laboratory in Wuhan; no definitive conclusion is reached.	China (Wuhan)
2020	Laboratory safety scrutiny	Global attention intensifies on biosafety standards, laboratory transparency, and pathogen research governance following the COVID-19 pandemic.	Global
2021 (May)	Official investigation milestone	The U.S. government directs intelligence agencies to assess the likelihood of a laboratory accident versus natural spillover as the origin of SARS-CoV-2.	United States
2020	Laboratory operations adjustment	Many high-containment laboratories reduce or suspend non-essential work during the COVID-19 pandemic to minimize accident risk under strained conditions.	Global
2021	Biosafety reporting initiative	International discussions advance proposals for standardized, transparent reporting of laboratory accidents involving high-risk pathogens.	Global
2022	Policy reassessment	The World Health Organization calls for stronger international frameworks governing high-risk pathogen research and laboratory safety.	Global
2022		Claims circulate that researchers at Boston University create a COVID-19 strain lethal to 80% of people, but the underlying study involves only animal experiments. Scientists engineer a chimeric SARS-CoV-2 combining the Omicron spike protein with an ancestral viral backbone to investigate why Omicron causes milder disease. Tests in transgenic mice show 100% mortality with the ancestral strain, 80% with the hybrid virus, and no deaths with Omicron. Experts emphasize that these findings cannot be generalized to humans.
2022	Biosafety audit expansion	Governments increase audits and reporting requirements for laboratories handling select agents following pandemic-era reviews.	United States; European Union
2023	Laboratory workforce concern	Reports highlight fatigue, staffing shortages, and training gaps as emerging risk factors for laboratory accidents.	Global
2023	Ongoing reassessments	Multiple intelligence agencies and scientific bodies maintain differing assessments regarding the plausibility of a COVID-19 lab-leak scenario, reflecting continued uncertainty.	Global
2024	Governance debate	Policymakers and scientists debate limits on gain-of-function and pathogen-enhancement research amid expanding global high-containment capacity.	Global
2024	Ongoing biosafety debate	Advances in synthetic biology and pathogen reconstruction renew concerns about accidental release risks from high-containment laboratories.	Global
2025	Ongoing biosafety challenge	The rapid adoption of AI-assisted biology and automated laboratories raises new questions about oversight, error propagation, and accidental release risks.	Global

Meta information on the timeline

How the timeline was built

The initial version of the timeline was written by FIXME.

Funding information for this timeline is available.

Feedback and comments

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What the timeline is still missing

• https://en.wikipedia.org/wiki/List_of_laboratory_biosecurity_incidents
• https://www.lemonde.fr/en/science/article/2022/11/13/virology-a-timeline-of-lab-accidents-biological-attacks-and-increasingly-dangerous-experiments_6004113_10.html
• https://www.openmindmag.org/articles/the-murky-history-of-lab-leaks
• https://reporter.rit.edu/features/lab-leaks-history
• https://www.independentsciencenews.org/health/the-long-history-of-accidental-laboratory-releases-of-potential-pandemic-pathogens/
• https://www.phe.gov/s3/BioriskManagement/biosecurity/Pages/History.aspx