View source for List of military nuclear accidents

{{Short description|none}}
This article lists notable military accidents involving nuclear material. Civilian accidents are listed at [[List of civilian nuclear accidents]]. For a general discussion of both civilian and military accidents, see [[nuclear and radiation accidents]]. For other lists, see [[Lists of nuclear disasters and radioactive incidents]].

==Scope of this article==
In listing military nuclear accidents, the following criteria have been adopted:
# There must be well-attested and substantial health risks associated with nuclear materials; or, it must involve nuclear weapons (even if lacking an installed fissile core or if nuclear detonation was not possible).
# To qualify as "military", the nuclear operation/material must be principally for military purposes.
# To qualify as "accident", the damage should not be intentional, unlike in [[nuclear warfare]].

This list may be incomplete due to military secrecy.

==1940s==
{{toptextcells}}
{| class="wikitable toptextcells"

|-
! Date
! Location
! Type
! Description

|-
| June 23, 1942 
| [[Leipzig]], [[Nazi Germany]]
| Steam explosion and reactor fire
| [[Leipzig L-IV experiment accident]]: Shortly after the Leipzig L-IV [[atomic pile]] – worked on by [[Werner Heisenberg]] and [[Robert Doepel]] – demonstrated Germany's first signs of neutron propagation, the device was checked for a possible [[heavy water]] leak. During the inspection, air leaked in, igniting the uranium powder inside. The burning uranium boiled the water jacket, generating enough steam pressure to blow the reactor apart. Burning uranium powder scattered throughout the lab causing a larger fire at the facility.<ref>R. Döpel (1941 bzw. 1942), [http://www.deutsches-museum.de/archiv/archiv-online/geheimdokumente/forschungszentren/leipzig/unfaelle/dokument-1/ Beschreibung zweier Unfälle mit Uranoxid].</ref><ref>{{cite journal |last=Goudsmit |first=S. A. |date=November 1947 |title=Heisenberg on the German Uranium Project |url=https://books.google.com/books?id=vA0AAAAAMBAJ&q=Leipzig%20pile%20fire&pg=PA343 |journal=Bulletin of the Atomic Scientists |publisher=Educational Foundation for Nuclear Science, Inc. |volume=3 |issue=1 |pages=343ff |doi=10.1080/00963402.1947.11459137 |bibcode=1947BuAtS...3k.343G |issn=0096-3402 |access-date=2014-06-26}}
</ref>

|-
| February 11, 1945
| [[Los Alamos National Laboratory]], [[Los Alamos, New Mexico]], United States 
| Accidental criticality
| During an experiment with the [[Dragon machine]] (a "fast burst" criticality experiment designed by [[Otto Robert Frisch|Otto Frisch]]), [[uranium hydride]] cubes were used in increasingly larger amounts. During the final experiment, 10<sup>15</sup> fissions were produced, blistering and swelling the cubes by approximately 1/8th of an inch. No personnel were injured.<ref>{{cite web|last1=Sanchez|first1=Rene Gerardo|last2=Hutchinson|first2=Jesson D.|title=History of Special Purpose Reactors and Critical Assemblies (LA-UR-24-23943)|url=https://www.osti.gov/servlets/purl/2342023|date=2024-04-25|publisher=Los Alamos National Laboratory|page=32}}</ref>

|-
| June 6, 1945
| [[Los Alamos National Laboratory]], [[Los Alamos, New Mexico]], United States 
| Accidental criticality
| A pseudosphere of 35.4 kg of [[highly enriched uranium]] (enriched to an average of 79.2% U-235) was put inside of a polyethylene box, and the box put into a tank that was filled with water. Before the tank was filled, the system unexpectedly went critical. An estimated 3-4×10<sup>16</sup> fissions occurred and the temperature of the metal may have risen to 200&nbsp;°C. Several personnel were exposed to non-lethal amounts of radiation, and the material was re-used for experiments within days.<ref>{{cite web|last1=Sanchez|first1=Rene Gerardo|last2=Hutchinson|first2=Jesson D.|title=History of Special Purpose Reactors and Critical Assemblies (LA-UR-24-23943)|url=https://www.osti.gov/servlets/purl/2342023|date=2024-04-25|publisher=Los Alamos National Laboratory|page=33}}</ref>

|-
| August 21, 1945
| [[Los Alamos National Laboratory]], [[Los Alamos, New Mexico]], United States 
| Accidental criticality
| [[Harry Daghlian]] dropped a [[tungsten carbide]] brick onto a [[plutonium]] core, inadvertently creating a [[critical mass]] at the Los Alamos Omega site. He quickly removed the brick, but was fatally [[radiation poisoning|irradiated]], and died on September 15.<ref>{{cite web | title = Harry K. Daghlian, Jr.: America's First Peacetime Atom Bomb Fatality | url =  http://members.tripod.com/~Arnold_Dion/Daghlian/ | access-date = 2007-06-17}}</ref>

|-
| May 21, 1946 
| [[Los Alamos National Laboratory]], Los Alamos, [[New Mexico]], United States
| Accidental criticality
| [[File:Slotin criticality drawing.jpg|right|250px|thumb|A sketch of [[Louis Slotin]]'s [[criticality accident]] used to determine exposure of those in the room at the time.]]

While demonstrating his technique to visiting scientists at Los Alamos, Canadian [[Nuclear physics|physicist]] [[Louis Slotin]] manually assembled a [[critical mass (nuclear)|critical mass]] of [[plutonium]]. A momentary slip of a screwdriver caused a [[prompt critical]] reaction. Slotin died on May 30 from massive radiation poisoning, with an estimated dose of 1,000 [[rad (unit)|rad]]s (rad), or 10 [[gray (unit)|grays]] (Gy). Seven observers, who received doses as high as 166 rads, survived, yet three died within a few decades from conditions believed to be radiation-related.<ref>{{cite journal | url=https://www.nytimes.com/1989/11/19/magazine/america-s-radiation-victims-the-hidden-files.html | title=America's Radiation Victims: The Hidden Files | author=Clifford T. Honicker | journal=The New York Times Magazine | date=November 19, 1989 | access-date=2011-04-23}}</ref>

Slotin worked with the same bomb core as Daghlian which became known as the "[[demon core]]." It was later melted down and combined with existing weapons-grade material.

|}

==1950s==
{| class="wikitable toptextcells"
|+
!Date
!Location
!Type
!Description
|-
|February 13, 1950
|British Columbia
| Non-nuclear detonation of an atomic bomb
|{{Main|1950 British Columbia B-36 crash}}
A [[United States Air Force|USAF]] [[Convair B-36 Peacemaker|B-36]] [[Bomber aircraft|bomber]] was flying a simulated combat mission from [[Eielson Air Force Base]], near [[Fairbanks, Alaska|Fairbanks]], Alaska, to [[Carswell Air Force Base]] in [[Fort Worth, Texas|Fort Worth]], Texas, carrying a [[Mark 4 nuclear bomb]] (minus a [[pit (nuclear weapon)|fissile core]]). After six hours of flight, the bomber experienced mechanical problems and was forced to shut down three of its six engines at an altitude of {{convert|12000|ft}}. Fearing that severe weather and icing would jeopardize a safe emergency landing, the weapon was jettisoned over the Pacific Ocean from a height of {{convert|8000|ft|abbr=on}}. The weapon's [[high explosive]]s detonated upon impact with a bright flash visible. All of the sixteen crew members and one passenger were able to parachute from the plane and twelve were subsequently rescued from [[Princess Royal Island]].<ref name="Tiwari">{{cite web|url=http://www.cdi.org/Issues/NukeAccidents/accidents.htm|title=U.S. Nuclear Weapons Accidents|author=Tiwari J, Gray CJ|archive-url=https://web.archive.org/web/20120423145613/http://www.cdi.org/issues/nukeaccidents/accidents.htm|archive-date=2012-04-23|access-date=2007-06-17}}</ref> The accident was categorized as a [[United States military nuclear incident terminology#Broken Arrow|Broken Arrow]], that is an accident involving a nuclear weapon but which does not present a risk of war.<ref>{{cite news|url=https://www.spiegel.de/international/world/a-nuclear-needle-in-a-haystack-the-cold-war-s-missing-atom-bombs-a-590513.html|title=The Cold War's Missing Atom Bombs|date=14 November 2008|work=Der Spiegel|access-date=20 August 2019|url-status=live|archive-url=https://web.archive.org/web/20190627105727/https://www.spiegel.de/international/world/a-nuclear-needle-in-a-haystack-the-cold-war-s-missing-atom-bombs-a-590513.html|archive-date=27 June 2019}}</ref>
|-
|April 11, 1950 
|[[Albuquerque, New Mexico]], US
|Non-nuclear detonation of an atomic bomb
|Three minutes after departure from [[Kirtland Air Force Base]] in Albuquerque a USAF [[Boeing B-29 Superfortress]] carrying a [[Mark 4 nuclear bomb]] (minus a [[pit (nuclear weapon)|fissile core]]), four spare detonators, and a crew of thirteen crashed into a mountain near [[Manzano Base]]. The crash resulted in a fire that ''[[The New York Times]]'' reported as being visible from {{convert|15|mi}}. The bomb's casing was demolished and its high explosives ignited upon contact with the plane's burning fuel. However, according to the [[United States Department of Defense|Department of Defense]], the four spare detonators and all nuclear components, including a "dummy capsule" simulating a nuclear core, were recovered. All thirteen crew members died.<ref name="Tiwari" />
|-
|July 13, 1950 
|[[Lebanon, Ohio|Lebanon]], Ohio, US
|Non-nuclear detonation of an atomic bomb
|A USAF [[B-50 Superfortress|B-50]] aircraft on a training mission from [[Biggs Army Airfield|Biggs Air Force Base]] with a [[Mark 4 nuclear bomb]] (minus a [[pit (nuclear weapon)|fissile core]]) flew into the ground resulting in a high-explosive detonation, but no nuclear explosion. The cause of the accident could not be established; the aircraft gave no signals of distress, and was flying on a clear day, but simply went into a steep dive and crashed nose-first, killing four officers and twelve airmen.<ref name="AFRRI">{{cite web|url=http://www.afrri.usuhs.mil/outreach/reports/pdf/SP86-2.pdf|title=DoD Mishaps|author=HR Lease|date=March 1986|publisher=[[Armed Forces Radiobiology Research Institute]]|url-status=dead|archive-url=https://web.archive.org/web/20081218233551/http://www.afrri.usuhs.mil/outreach/reports/pdf/SP86-2.pdf|archive-date=2008-12-18|access-date=2008-12-04}}</ref><ref name="summary1978">{{Cite web|title=Summary of Nuclear Weapon/Material Accidents and Related Explosive Ordnance Disposal (EOD) Activities (RS 1210/24)|author=Sandia Laboratories|date=December 14, 1978|url=https://www.governmentattic.org/40docs/NNSApost1980BrokenArrow_2021.pdf|publisher=Sandia National Laboratories (via Government Attic)}} (report begins on page 117 of the PDF)</ref>
|-
|August 5, 1950
|[[Travis Air Force Base|Fairfield-Suisun AFB]], California, US
|Non-nuclear detonation of an atomic bomb
|{{Main|1950 Fairfield-Suisun Boeing B-29 crash}}
A USAF B-29 bomber with a [[Mark 4 nuclear bomb]] (minus a [[pit (nuclear weapon)|fissile core]]) on board, flying to [[Guam]], experienced malfunctions with two propellers and with landing gear retraction during take-off and crashed while attempting an emergency landing at Fairfield Suisun-AFB. In the resulting fire, the bomb's high-explosive material exploded, killing nineteen people from the crew and rescue personnel. [[Brigadier general (United States)|Brigadier General]] [[Robert F. Travis]], command pilot of the bomber, was among the dead.<ref>[http://www.check-six.com/Crash_Sites/Travis_B-29_crash_site.htm The Crash of the B-29 on Travis AFB, CA August 5, 1950], ''Check-six.com''.</ref>
|-
|November 10, 1950
|[[Rivière-du-Loup]], [[Québec]], Canada
|Non-nuclear detonation of an atomic bomb
|{{Main|1950 Rivière-du-Loup B-50 nuclear weapon loss incident}}
Returning one of several U.S. [[Mark 4 nuclear bomb]]s (minus a [[pit (nuclear weapon)|fissile core]]) secretly deployed in Canada, a USAF [[B-50 Superfortress|B-50]] [[1950 Rivière-du-Loup B-50 nuclear weapon loss incident|had engine trouble and jettisoned the weapon]] at {{convert|10500|ft}}. The crew set the bomb to self-destruct at {{convert|2500|ft|abbr=on}} and dropped over the [[St. Lawrence River]]. The explosion shook area residents and scattered nearly {{convert|100|lb}} of [[uranium]] (U-238) used in the weapon's tamper.<ref>{{cite journal|last1=Norris|first1=Robert S.|last2=Arkin|first2=William M.|last3=Burr|first3=William|year=1999|title=Where they were|url=http://www-personal.umich.edu/~sanders/214/other/news/nd99norris.pdf <!-- http://www.bullatomsci.org/issues/1999/nd99/nd99norris.html is a dead link -->|journal=Bulletin of the Atomic Scientists|volume=55|issue=6|pages=26–35|doi=10.2968/055006011}}</ref>
|-
|March 1, 1954
|[[Bikini Atoll]], [[Marshall Islands|Republic of the Marshall Islands]] (then [[Trust Territory of the Pacific Islands]])
|Nuclear test accident
|[[File:Bravo Fallout.jpg|right|200px|thumb|The [[Castle Bravo]] fallout pattern.]]During the [[Castle Bravo test]] of the first deployable [[Thermonuclear weapon|hydrogen bomb]], a miscalculation resulted in the explosion being over twice as large as predicted, with a total explosive force of {{convert|15|MtonTNT|lk=on}}. Of the total yield, {{convert|10|MtonTNT|lk=in|abbr=on}} were from fission of the natural uranium tamper, but those fission reactions were quite [[Dirty bomb#Other uses of the term|dirty]], producing a large amount of [[Nuclear fallout|fallout]]. Combined with the much larger than expected yield and an unanticipated wind shift, [[nuclear radiation|radioactive]] fallout spread into unexpected areas. A Japanese [[fishing boat]], the ''[[Daigo Fukuryū Maru|Daigo Fukuryu Maru/Lucky Dragon]]'', came into contact with the fallout, which caused many of the crew to become ill, with one fatality. The fallout spread eastward onto the inhabited [[Rongelap Atoll|Rongelap]] and [[Rongerik Atoll]]s. These islands were not evacuated before the explosion due to the unanticipated fallout zone and the financial cost involved, but many of the [[Marshall Islands]] natives have since suffered from radiation burns and radioactive [[dust]]ing and also similar fates as the Japanese fishermen and have received little, if any, compensation from the [[U.S. government|federal government]].<ref>{{cite web|url=http://america.aljazeera.com/articles/2015/7/28/bikini-nuclear-test-survivors-demand-compensation.html|title=Bikinians evacuated 'for good of mankind' endure lengthy nuclear fallout|author=Renee Lewis|date=2015-07-28|access-date=2016-09-11}}</ref> The test resulted in an international uproar and reignited Japanese concerns about radiation, especially with regard to the possible [[Radioactive contamination|contamination]] of fish. Personal accounts of the Rongelap people can be seen in the documentary ''Children of Armageddon''.
|-
|November 29, 1955
|[[Idaho]], US 
|Partial meltdown
|Operator error led to a partial [[core meltdown]] in the experimental [[Experimental Breeder Reactor I|EBR-I]] [[breeder reactor]], resulting in temporarily elevated radioactivity levels in the reactor building and necessitating significant repair.<ref>{{cite web|url=https://www.cdc.gov/niosh/ocas/pdfs/tbd/anlw2.pdf|title=Dose Reconstruction Project for NIOSH|author=Rohrig ND|date=2004-09-09|access-date=2007-06-17}}</ref><ref>{{cite web|url=http://mt.sopris.net/mpc/industrial/nuclear.operations.html|title=Industrial/Warnings of Serious Risks for Nuclear Reactor Operations|archive-url=https://web.archive.org/web/20050405204941/http://mt.sopris.net/mpc/industrial/nuclear.operations.html|archive-date=2005-04-05|access-date=2007-06-17}}</ref>
|-
|March 10, 1956
|Over the [[Mediterranean Sea]]
|Loss of two capsules of nuclear weapons material in carrying cases
|{{Main|1956 B-47 disappearance}}
A USAF [[B-47 Stratojet]] on a non-stop mission from [[MacDill Air Force Base]], Florida, to an overseas base descended into a cloud formation at 14,000 feet over the Mediterranean in preparation for an in-air refueling and vanished while transporting two capsules of [[nuclear weapon]]s material in carrying cases (and no complete weapons; a nuclear detonation was not possible).<ref>{{Cite web |url=http://www.dod.mil/pubs/foi/operation_and_plans/NuclearChemicalBiologicalMatters/21.pdf |title=DEPARTMENT OF DEFENSE – NARRATIVE SUMMARIES OF ACCIDENTS INVOLVING U.S. NUCLEAR WEAPONS 1950–1980 |access-date=20 November 2011 |archive-url=https://web.archive.org/web/20140113030431/http://www.dod.mil/pubs/foi/operation_and_plans/NuclearChemicalBiologicalMatters/21.pdf |archive-date=13 January 2014 |url-status=dead  }}</ref> A French news agency reported that the plane had exploded in the air Northeast of [[Saïdia]], in French Morocco in the same general location of its last known position. The plane was lost while flying through dense clouds, and no trace of the cores and other wreckage was ever located.<ref>{{cite web|url=http://www.aerospaceweb.org/question/weapons/q0268.shtml|title=Broken Arrow Nuclear Weapon Accidents|access-date=2008-11-29}}</ref><ref>{{cite web|url=http://www.check-six.com/lib/Famous_Missing/Broken_Arrow_B47.htm|title=Broken Arrow B-47|access-date=2008-11-29}}</ref><ref name="CG-HR-3">{{cite web|url=https://fas.org/sgp/othergov/doe/cg-hr-3/appb.pdf|title=Historical Records Declassification Guide, CG-HR-3, U.S. Department of Energy, Appendix B|date=October 2005|publisher=Office of Classification and Information Control, DoE}}</ref> 
|-
|July 27, 1956
|[[RAF Lakenheath]] in Suffolk, UK 
|Nuclear weapons damaged
|{{Main|RAF Lakenheath nuclear weapons accidents}}
A USAF [[B-47 Stratojet|B-47]] crashed into a [[Weapons Storage and Security System#History|storage igloo]], spreading burning fuel over three [[Mark 6 nuclear bomb]]s at [[RAF Lakenheath]]. A bomb disposal expert stated it was a miracle exposed detonators on one bomb did not fire.<ref>{{cite web|url=http://www.gwu.edu/~nsarchiv/nsa/NC/nh4_1.gif|title=nh4_1.gif|url-status=dead|archive-url=https://web.archive.org/web/20000519154728/http://www.gwu.edu/~nsarchiv/nsa/NC/nh4_1.gif|archive-date=2000-05-19|access-date=2007-06-17}}</ref> The weapons were in a storage configuration and there were no fissile capsules inside the weapons or the igloo.<ref name="summaryaccidents">{{Cite web|title=Narrative Summaries of Accidents Involving U.S. Nuclear Weapons, 1950-1996|author=U.S. Department of Defense and U.S. Department of Energy|date=1996|url=https://www.governmentattic.org/40docs/NNSApost1980BrokenArrow_2021.pdf|publisher=Sandia National Laboratories (via Government Attic)}} (report begins on page 359 of the PDF)</ref>
|-
|May 22, 1957
|[[Kirtland AFB]] in [[New Mexico]], US 
|Non-nuclear detonation of a [[Mark 17 nuclear bomb|Mark 17]] thermonuclear bomb<ref>{{cite news|url=https://www.latimes.com/archives/la-xpm-1986-08-27-mn-14421-story.html|title=Accident Revealed After 29 Years: H-Bomb Fell Near Albuquerque in 1957|date=August 27, 1986|access-date=31 August 2014|work=Los Angeles Times|agency=Associated Press}}</ref>
|A B-36 ferrying a [[Mark 17 nuclear bomb|Mark 17]] nuclear bomb from [[Biggs Air Force Base|Biggs AFB]] to [[Kirtland Air Force Base|Kirtland AFB]] dropped a thermonuclear weapon on approach to Kirtland. The weapon struck the ground 4.5 miles south of the Kirtland control tower and 0.3 miles west of the [[Sandia Base]] reservation. The weapon was completely destroyed by the detonation of its high explosive material, creating a crater 12 feet (3.7 m) deep and 25 feet (7.62 m) in diameter.  Radioactive contamination at the crater lip amounted to 0.5 [[milliroentgen]].<ref name="CG-HR-3" /> The aircraft contained a nuclear capsule, containing the fissile core for the weapon, but it was not installed in the weapon at the time of the accident, and was not involved in the explosion of the weapon.<ref name="summaryaccidents"></ref>
|-
|July 28, 1957
|Atlantic Ocean 
|Two nuclear weapons jettisoned and not recovered
|A USAF [[C-124 Globemaster II|C-124]] aircraft from [[Dover Air Force Base]], [[Delaware]] was carrying three weapons and one nuclear capsule aboard the aircraft at the time. Nuclear components were not installed in the weapons.  While flying over the Atlantic Ocean, the aircraft experienced a loss of power. For their own safety, the crew jettisoned two bombs which were never recovered.<ref name="AFRRI" /> Neither of the weapons detonated. The C-124 landed later with the other weapon and the nuclear capsule.<ref name="summaryaccidents"></ref>
|-
|September 11, 1957
|[[Rocky Flats Plant]], [[Golden, Colorado|Golden]], Colorado, US
|Fire, release of nuclear materials
|{{Main|Radioactive contamination from the Rocky Flats Plant}}
A fire began in a theoretically fireproof area inside the [[plutonium]] processing building, in a [[glovebox]] used to handle radioactive materials, igniting the combustible rubber gloves and [[plexiglas]] windows of the box.  The fire quickly spread to the plutonium as various safety features failed. The fire spread through the ventilation system as the containment ability of the facility became compromised, with plumes of radioactive smoke sent high into the outside air. The fire raged inside the building for 13 hours over the night of the 11th & 12th before firefighters could finally extinguish it. In the aftermath, [[United States Department of Energy|Department of Energy]] officials, and the [[Dow Chemical Company|Dow Chemical]] officials who ran the facility, did not admit the extent of the catastrophe, or the radiation danger, to local officials or the media. Knowledge of the extent of the damage and contamination was kept from the public for years. After the fire, plutonium was detected near a school {{convert|12|miles|km}} away and around [[Denver]] {{convert|17|miles|km}} away. An independent group of scientists conducting off-site testing 13 years later found plutonium contamination in areas in nearby [[Rocky Flats National Wildlife Refuge|Rocky Flats]] to be 400 to 1,500 times higher than normal, higher than any ever recorded near any urban area, including [[Atomic bombing of Nagasaki|Nagasaki]]. The [[United States Atomic Energy Commission|Atomic Energy Commission]] then conducted its own off-site study, and that study confirmed plutonium contamination as far as {{convert|30|miles|km}} from the plant.<ref>{{cite web|url=http://www.energy-net.org/01NUKE/nhistory.htm|title=A Brief History of Nuclear Fission and its Opposition|access-date=2007-06-17}}</ref><ref>{{cite web|url=https://www.colorado.gov/pacific/sites/default/files/HM_sf-rocky-flats-1957-fire.pdf|title=1957 Fire|work=Citizen Summary: Rocky Flats Historical Public Exposures Studies|access-date=2007-06-17|archive-date=2021-06-24|archive-url=https://web.archive.org/web/20210624203229/https://www.colorado.gov/pacific/sites/default/files/HM_sf-rocky-flats-1957-fire.pdf|url-status=dead}}</ref><ref>{{cite web|url=http://www.racteam.com/Experience/Publications/RF_1957_Fire_Risk.htm|title=Estimated Exposure and Lifetime Cancer Incidence Risk from Plutonium Released from the 1957 Fire at the Rocky Flats Plant|author=Rood AS, Grogan HA|work=RAC Report No. 2-CDPHE-RFP-1999-FINAL|archive-url=https://web.archive.org/web/20061229235048/http://www.racteam.com/Experience/Publications/RF_1957_Fire_Risk.htm <!-- Bot retrieved archive -->|archive-date=2006-12-29|access-date=2007-06-17}}</ref><ref>{{cite book|author=Wasserman H, Solomon N|url=http://www.ratical.org/radiation/KillingOurOwn/KOO8.html|title=Bomb Production at Rocky Flats: Death Downwind. In: Killing Our Own: The Disaster of America's Experience with Atomic Radiation|year=1982|publisher=Delta|isbn=0-440-04567-3|access-date=2007-06-17}}</ref>
|-
|September 29, 1957
|[[Kyshtym]], [[Chelyabinsk Oblast]], [[Russian Soviet Federative Socialist Republic]], [[Union of Soviet Socialist Republics|USSR]] (now [[Russian Federation]])
|Explosion, release of nuclear materials
|{{Main|Kyshtym disaster}}
A [[Nuclear reactor coolant|cooling system]] [[catastrophic failure|failure]] at the [[Mayak]] nuclear processing plant resulted in a major explosion and release of radioactive materials. A large area was subjected to [[radioactive contamination]] and thousands of local inhabitants were evacuated.<ref>{{cite web|url=http://www1.american.edu/TED/URAL.HTM|title=Ural Mountains Nuclear Waste|url-status=dead|archive-url=https://web.archive.org/web/20070630140845/http://www.american.edu/ted/ural.htm|archive-date=2007-06-30|access-date=2007-06-17}}</ref>
|-
|October 8–12, 1957
|[[Sellafield]], Cumbria, UK 
|Reactor core fire
|{{Main|Windscale fire}}
Technicians mistakenly overheated Windscale [[Pile (nuclear reactor)|Pile]] No. 1 during an [[annealing (metallurgy)|annealing]] process to release [[Wigner energy]] from [[graphite]] portions of the reactor. Poorly placed temperature sensors indicated the reactor was cooling rather than heating. The excess heat led to the failure of a nuclear cartridge, which in turn allowed uranium and irradiated graphite to react with air. The resulting fire burned for days, damaging a significant portion of the reactor core. About 150 burning fuel cells could not be removed from the core, but operators succeeded in creating a [[firebreak]] by removing nearby fuel cells. An effort to cool the graphite core with water and the switching off of the air cooling system eventually quenched the fire. The reactor had released radioactive gases into the surrounding countryside, primarily in the form of [[iodine-131]] (<sup>131</sup>I). Milk distribution was banned in a {{convert|200|sqmi|adj=on}} area around the reactor for several weeks. A 1987 report by the [[National Radiological Protection Board]] predicted the accident would cause as many as 100 long-term cancer deaths, although the [[Medical Research Council (United Kingdom)|Medical Research Council Committee]] concluded that "it is in the highest degree unlikely that any harm has been done to the health of anybody, whether a worker in the Windscale plant or a member of the general public." The reactor that burned was one of two air-cooled, graphite-moderated natural uranium reactors at the site used for production of [[plutonium]].<ref>{{cite web|url=http://www.nucleartourist.com/events/windscal.htm|title=Windscale Nuclear Incident|date=2005-12-22|work=The Virtual Nuclear Tourist|access-date=2007-06-17|archive-url=https://web.archive.org/web/20060424074257/http://www.nucleartourist.com/events/windscal.htm|archive-date=2006-04-24|url-status=dead}}</ref><ref>{{cite web|url=http://www.lakestay.co.uk/1957.htm|title=The 1957 Windscale Fire|access-date=2007-06-17}}</ref><ref>{{cite web|url=http://www.globalsecurity.org/wmd/world/uk/sellafield.htm|title=Sellafield|date=2005-04-28|work=United Kingdom Nuclear Forces|access-date=2007-06-17}}</ref> A 2007 study concluded that because the actual amount of radiation released in the fire could be double the previous estimates, and that the radioactive plume actually travelled further east, there were 100 to 240 cancer fatalities in the long term as a result of the fire.<ref name="BBC Windscale">{{cite news |last1=Black |first1=Richard |title=Fukushima – disaster or distraction? |url=https://www.bbc.co.uk/news/science-environment-12789749 |access-date=30 June 2020 |work=BBC News |date=18 March 2011}}</ref><ref name="Irish Times Windscale">{{cite news |last1=Ahlstrom |first1=Dick |title=The unacceptable toll of Britain's nuclear disaster |url=https://www.irishtimes.com/news/the-unacceptable-toll-of-britain-s-nuclear-disaster-1.970400 |access-date=15 June 2020 |newspaper=The Irish Times |date=8 October 2007}}</ref><ref name="2007 Telegraph">{{cite news |last1=Highfield |first1=Roger |title=Windscale fire: 'We were too busy to panic' |url=https://www.telegraph.co.uk/news/science/science-news/3309842/Windscale-fire-We-were-too-busy-to-panic.html |access-date=15 June 2020 |work=The Telegraph |date=9 October 2007 |archive-url=https://web.archive.org/web/20200615223147/https://www.telegraph.co.uk/news/science/science-news/3309842/Windscale-fire-We-were-too-busy-to-panic.html |archive-date=15 June 2020 |url-status=live }}</ref>
|-
|October 11, 1957 
|[[Homestead Air Force Base]], Florida
|Nuclear bomb burned after B-47 aircraft accident
|B-47 aircraft crashed during take-off after a wheel exploded; one [[Mark 15 nuclear bomb|Mark 15 Mod 0]] nuclear bomb burned in the resulting fire.<ref name="DOD1981">{{cite web|url=http://www.dod.gov/pubs/foi/reading_room/21.pdf|title=Narrative Summary of Accidents Involving U.S. Nuclear Weapons 1950–1980|date=April 1981|publisher=[[United States Department of Defense]]|url-status=dead|archive-url=https://web.archive.org/web/20100528154819/http://www.dod.gov/pubs/foi/reading_room/21.pdf|archive-date=2010-05-28|access-date=2009-04-23}}</ref> The aircraft was carrying the unarmed weapon in a ferry configuration in the bomb bay, and the nuclear capsule in the crew compartment. Two "low-order" explosions occurred during the two hours that the plane and weapons burned. The nuclear capsule was recovered intact with minor damage.<ref name="summaryaccidents"></ref> The "pit" of the bomb itself melted and re-solidified within the weapon case.<ref name="summary1978"></ref>
|-
|January 31, 1958
|[[Sidi Slimane Air Base]], Morocco
|Nuclear bomb damaged in crash<ref name="DOD1981" />
|During a simulated takeoff, a wheel casting failure caused the tail of a [[U.S. Air Force|USAF]] B-47 carrying a [[Mark 36 nuclear bomb|Mark 36 Mod 1]] nuclear bomb to hit the runway, rupturing a fuel tank and sparking a fire which burned for some 7 hours.<ref>Schlosser identifies the weapon as a Mark 36 bomb: {{cite web|last=Schlosser|first=Eric|title= Accidents will happen: An excerpt from ''Command and Control''|date=3 March 2014|publisher=Bulletin of the Atomic Scientists|url=https://thebulletin.org/2014/03/accidents-will-happen-an-excerpt-from-command-and-control/}} A USAF historical report indicates that only the Mark 36 Mod 1 and the Mark 6 bombs were stored at Sidi Slimane: {{cite web|url=https://www.nukestrat.com/us/afn/SACdep58.PDF|title=History of the Strategic Air Command, 1 January 1958–30 June 1958|author=US Air Force|publisher=Air Force Historical Research Center|date=1958}}</ref> The weapon used in-flight insertion and the weapon was in its retracted, unarmed state.<ref>See Accident #24 on page 4 of this report: {{cite web|url=https://www.pbs.org/wgbh/americanexperience/media/filer_public/24/db/24dbd8c1-c74a-4841-ab63-c3258a14ceb4/_cc_afswp_technical_incidents_reduced1.pdf|title=Accidents and Incidents Involving Nuclear Weapons (DASA Technical Letter 20-3)|author=Defense Atomic Support Agency|website=[[PBS]] |date=1 March 1966}}</ref> The high explosives in the weapon burned but did not detonate, but the weapon capsule melted and "settled into a molten slag of the burned aircraft and bomb." A report described the slag as former "a slab of slag material weighing approximately 8,000 pounds, approximately 6 to 8 feet wide and 12 to 15 feet in length with a thickness of 10 to 12 inches," and that a jackhammer was used to break it into smaller pieces, with the "hot" pieces carted out, but the rest buried nearby. Some contamination was detected immediately following the accident in the remains of the airplane and weapon, as well as part of the runway, and [[explosive ordnance disposal]] crew tracked contamination on their shoes and clothing back to their home base.<ref name="DOD1981" /><ref>{{cite journal|year=1981|title=U.S. Department of Defense Nuclear Weapons Accident 1950–1980: Introduction |url=http://www.milnet.com/cdiart.htm|journal=The Defense Monitor|issn=0195-6450|archive-url=https://web.archive.org/web/20090923002908/http://www.milnet.com/cdiart.htm|archive-date=2009-09-23|access-date=2007-06-17}}</ref><ref name="GlobalSecurity">{{cite web|url=http://www.globalsecurity.org/wmd/ops/broken-arrow.htm|title=Broken Arrows|date=2005-04-28|work=United Kingdom Nuclear Forces|access-date=2007-06-17}}</ref><ref name="summary1978"></ref><ref>Re: the slab and the jackhammer, see: {{cite web|last=Schlosser|first=Eric|title= Accidents will happen: An excerpt from ''Command and Control''|date=3 March 2014|publisher=Bulletin of the Atomic Scientists|url=https://thebulletin.org/2014/03/accidents-will-happen-an-excerpt-from-command-and-control/}}</ref> After the accident, B-47 flights were temporarily suspended pending inspection of their wheels for defects.<ref name="summaryaccidents"></ref>
|-
|February 5, 1958 
|[[Savannah, Georgia|Savannah]], Georgia, US 
|Unarmed nuclear bomb lost
|{{Main|1958 Tybee Island mid-air collision}}
A USAF B-47 bomber jettisoned a [[Mark 15 nuclear bomb|Mark 15 Mod 0 nuclear bomb]] (the nuclear capsule was not aboard the aircraft; the bomb contained a simulated 150-pound (68 kg) capsule made of lead) over the Atlantic Ocean after a [[midair collision]] with a USAF [[North American F-86 Sabre|F-86 Sabre]] during a simulated combat mission from [[Homestead Air Force Base]], Florida. The F-86's pilot [[ejection seat|ejected]] and [[parachute]]d to safety.<ref name="Natola">{{Cite book|title=Boeing B-47 Stratojet|publisher=Schiffer Publishing Ltd.|year=2002|isbn=0764316702|editor=Mark Natola|pages=77–80}}</ref>  The USAF claimed the B-47 tried landing at [[Hunter Air Force Base]], Georgia three times before the bomb was jettisoned at {{convert|7200|ft|abbr=on}} near [[Tybee Island, Georgia|Tybee Island]], Georgia. The B-47 pilot successfully landed in one attempt only after he first jettisoned the bomb.  A {{convert|3|sqmi|adj=on}} area near [[Wassaw Sound]] was searched for nine weeks before the search was called off.
|-
|February 28, 1958
|[[RAF Greenham Common|Greenham Common US Base]], [[Newbury, Berkshire|Newbury]], England
|
|A [[B-47E]] of the [[310th Bomb Wing]] developed problems shortly after takeoff and jettisoned its two 1,700 gallon external fuel tanks. They missed their designated safe impact area, and one hit a hangar while the other struck the ground 65 feet (20 m) behind a parked B-47E. The parked plane, which was fuelled, had a pilot on board, and was carrying a 1.1 megaton (4.6 PJ) [[B28 nuclear bomb]], was engulfed by flames. The conflagration took sixteen hours and over a million gallons of water to extinguish, partly because of the magnesium alloys used in the aircraft. Although two men were killed and eight injured, the US and UK governments kept the accident secret: as late as 1985, the British government claimed that a taxiing aircraft had struck a parked one and that no fire was involved.
|-
|March 11, 1958
|[[Mars Bluff, South Carolina|Mars Bluff]], South Carolina
|Non-nuclear detonation of a nuclear bomb
|{{Main|1958 Mars Bluff B-47 nuclear weapon loss incident}}
A USAF [[Boeing B-47 Stratojet|B-47E bomber]], number 53-1876A, was flying from [[Hunter Air Force Base]] in [[Savannah, Georgia|Savannah]], Georgia, to England in a formation of four B-47s on a top-secret mission called [[Operation Snow Flurry]] to perform a mock bombing exercise. The flight navigator/bombardier was checking the locking harness on the massive ({{convert|7600|lb|0}}) [[Mark 6 nuclear bomb]] when he accidentally pushed the emergency release lever. The bomb fell on the bomb-bay doors, smashing them open and going into a {{convert|15,000|ft|0}} free fall. The high-explosive detonator went off after it hit the ground 6.5 [[Statute mile|miles]] [[Cardinal direction|east]] of [[Florence, South Carolina|Florence]], South Carolina, in [[Mars Bluff, South Carolina#Nuclear bomb accident|Mars Bluff]], creating a {{convert|70|ft|0}} wide crater, {{convert|30|ft|0}} deep.<ref>{{cite web|url=https://news.google.com/newspapers?id=VHVLAAAAIBAJ&pg=6195,966992&dq=florence+h+bomb+hunter&hl=en|title=Accident Stirs Concern Here And in Britain|work=Oxnard Press-Courier|date=March 12, 1958|via=news.google.com|access-date=13 April 2018}}</ref> A nearby house was destroyed and several people were injured.<ref name="Natola" />{{rp|136–137}}<ref>[http://www.thecolumbiastar.com/news/2008-03-21/news/036.html Atomic Bomb dropped on Florence, S.C., March 11, 1958].</ref> The weapon did not have an installed nuclear capsule at the time of the accident, and so a nuclear detonation was not possible. There was a nuclear capsule onboard the plane, in another section of the aircraft.<ref name="summaryaccidents"></ref>
|-
|June 16, 1958
|[[Oak Ridge, Tennessee]], US
|Accidental criticality
|A supercritical portion of highly enriched [[uranyl nitrate]] was allowed to collect in the drum causing a [[prompt critical|prompt neutron criticality]] in the C-1 wing of building 9212 at the [[Y-12 National Security Complex|Y-12]] complex. It is estimated that the reaction produced 1.3&nbsp;×&nbsp;10<sup>18</sup><!-- <math>\begin{smallmatrix}1.3 * 10^{18}\end{smallmatrix}</math> --> fissions. Eight employees were in close proximity to the drum during the accident, receiving [[neutron radiation|neutron]] doses ranging from 30 to 477 [[Röntgen equivalent man|rems]]. No fatalities were reported.<ref name="Walker">{{cite web|url=http://www.abomb1.org/accident/critical.html|title=Criticality Accidents|author=Walker G|work=Trinity Atomic Web Site|access-date=2007-06-17}}</ref>
|-
|November 4, 1958 
|[[Dyess Air Force Base]], Texas, US
|Non-nuclear detonation of a nuclear bomb
|A USAF [[Boeing B-47 Stratojet|B-47 bomber]] developed a fire shortly after take-off and went down with a sealed-pit [[Mark 39 nuclear bomb|Mark 39 Mod 1]] nuclear weapon on board from an altitude of {{convert|1500|ft|abbr=on}}. The detonation of the high explosive material in the bomb created a crater 6 feet (1.8 m) deep and 35 feet (10.7 m) in diameter. Three crew members escaped, and one was killed.<ref>[http://www.military1.com/air-force/article/271002-air-force-concludes-clean-up-at-old-b-47-nuclear-bomb-crash-site Air Force concludes clean up at old B-47 nuclear bomb crash site], ''Military1.com''</ref> All weapons components were ultimately accounted for, after digging for them in the crater.<ref name="summaryaccidents"></ref><ref name="summary1978"></ref>
|-
|November 26, 1958
|[[Chennault Air Force Base]], [[Louisiana]], US
|Non-nuclear detonation of a nuclear bomb
|A USAF [[Boeing B-47 Stratojet|B-47 bomber]] with a sealed-pit nuclear weapon on board developed a fire while on the ground. The aircraft wreckage and the site of the accident were contaminated after a limited explosion of non-nuclear material.<ref>Rebecca Grant. [http://www.airforcemag.com/magazinearchive/pages/2011/august%202011/0811dome.aspx The Perils of Chrome Dome], ''Air Force Magazine'', Vol. 94, No. 8, August 2011.</ref>

|-
|December 30, 1958 
|[[Los Alamos, New Mexico]], US
|Accidental criticality
|During chemical purification, a [[critical mass]] of a plutonium solution was accidentally assembled at [[Los Alamos National Laboratory]]. A chemical operator named [[Cecil Kelley criticality accident|Cecil E. Kelley]] died of [[Acute radiation syndrome|acute radiation sickness]]. The March 1961 ''[[Journal of Occupational and Environmental Medicine]]'' printed a special supplement medically analyzing this accident. Hand manipulation of critical assemblies was abandoned as a matter of policy in U.S. federal facilities after this accident.<ref name="Walker" />
|-
|January 18, 1959
|[[Osan Air Base]], South Korea
|Nuclear weapon on fire
|A parked USAF [[North American F-100 Super Sabre|F-100C Super Sabre]], loaded with a nuclear weapon, developed a fire after its external fuel tanks were dropped and exploded during a practice alert. The resulting fire was put out in seven minutes and there was no nuclear explosion.<ref>Maggelet, Michael H., and James C. Oskins. ''[https://books.google.com/books?id=DF1RAgAAQBAJ&pg=PA88&lpg=PA88&dq=Pacific+USAF+base+F-100+1959+nuclear+accident Broken Arrow: A Disclosure of Significant U.S., Soviet, and British Nuclear Weapon Incidents and Accidents, 1945–2008]''. Volume II. Raleigh, NC: Lulu, 2010.</ref> When originally disclosed in 1980, the location was identified as a base in the Pacific region. In 2016, the newspaper ''[[The Asahi Shimbun|Asahi Shimbun]]'' reported that the location of the accident was [[Osan Air Base]].<ref>Gil Yun-hyung.''[http://english.hani.co.kr/arti/english_edition/e_international/728975.html Osan Air Base the site of 1959 nuclear weapon-related accident, Japanese paper reports]''</ref>
|-
|July 6, 1959
|[[Barksdale Air Force Base|Barksdale AFB]], Louisiana, US
|Limited contamination
|A USAF [[Douglas C-124 Globemaster II|C-124]] transporting three [[Mark 39 nuclear bomb|Mark 39 Mod 2]] sealed-pit nuclear weapons crashed and burned down during take-off. The high explosives did not detonate, but one weapon was completely destroyed by the fire, and the other two suffered heat damage and [[tritium]] leakage. The wreckage area experienced limited contamination.<ref name="summary1978"></ref>
|-
|September 25, 1959
|Eastern Pacific Ocean
|Lost nuclear weapon casing
|A U.S. Navy [[Martin P5M Marlin|P5M]] [[Antisubmarine warfare|antisubmarine]] aircraft patrolling out of NAS Whidbey Island with an unarmed Mark 90 [[nuclear depth charge]] casing on board [[Water landing|crash-landed]] in the Pacific Ocean, about 100 miles (160 km) west of the Washington-Oregon border.<ref name="Gibson">Gibson, James N. ''Nuclear Weapons of the United States – An Illustrated History''. Atglen, PA: Schiffer Publishing Ltd., 1996, {{LCCN|9667282}}, {{ISBN|0-7643-0063-6}},  Chapter 12, "Nuclear Anti-Submarine Weapons", p. 214.</ref> The casing was not recovered.<ref>{{cite news|author=Richard Halloran|url=https://www.nytimes.com/1981/05/26/us/us-discloses-accidents-involving-nuclear-weapons.html|title=U.S. discloses accidents involving nuclear weapons|date=May 26, 1981|newspaper=The New York Times}}</ref>
|-
|October 15, 1959
|[[Hardinsburg, Kentucky]], US
|Nuclear weapon partially damaged
|After both planes took off from [[Columbus Air Force Base]] in [[Mississippi]], a USAF [[Boeing B-52 Stratofortress|B-52F-100-BO]] (No. 57-036), with two sealed-pit nuclear weapons [[midair collision|collided]] at {{convert|32,000|ft|0}} with a [[KC-135]] [[tanker aircraft|refueling aircraft]] (No. 57-1513), during a [[midair refueling|refueling procedure]] near Hardinsburg, Kentucky. Both planes crashed killing eight crew members. One unarmed nuclear weapon was partially damaged, but no contamination resulted.<ref>[http://www.ksla.com/story/8708856/listing-of-b-52-crashes-since-1957 Listing of B-52 crashes since 1957], ''KSLA News, Channel 12''</ref>
|-
|November 20, 1959
|[[Oak Ridge, Tennessee]], US
|Explosion
|A [[chemical explosion]] occurred during [[decontamination]] of processing machinery in the radiochemical processing plant at [[Oak Ridge National Laboratory]] in [[Tennessee]] . (Report ORNL-2989, Oak Ridge National Laboratory). The accident resulted in the release of about {{convert|15|g|lk=on}} of [[Plutonium-239|<sup>239</sup>Pu]].
|}

==1960s==
{| class="wikitable toptextcells"
|+
!Date
!Location
!Type
! Description
|-
|June 7, 1960
|[[New Egypt, New Jersey]], US
|Nuclear warhead damaged by fire
|A [[helium]] tank exploded and ruptured the fuel tanks of a USAF [[BOMARC]]-A [[surface-to-air missile]] at [[McGuire Air Force Base]], [[New Jersey]]. The fire destroyed the missile, and contaminated the area directly below and adjacent to the missile.<ref name="GlobalSecurity" /><ref>{{Cite news|last=Gambardello|first=Joseph A.|title=Plutonium Spill Neither Gone Nor Forgotten, 40 Years Later|date=1 June 2000|newspaper=[[The Philadelphia Inquirer]]|location=[[Philadelphia]]|page=A01}}</ref>
|-
|October 13, 1960
|[[Barents Sea]], Arctic Ocean 
|Release of nuclear materials
|A leak developed in the [[steam generator]]s and in a pipe leading to the compensator reception on the ill-fated {{ship|Soviet submarine|K-8||2}} while the [[Soviet Navy|Soviet]] [[Red Banner Northern Fleet|Northern Fleet]] {{sclass2|November|submarine|0}} [[Nuclear submarine|submarine]] was on [[Military exercise|exercise]]. While the crew rigged an improvised [[Nuclear reactor coolant|cooling system]], [[Radiation leak|radioactive gases]] leaked into the vessel and three of the crew suffered visible radiation injuries according to radiological experts in Moscow. Some crew members had been exposed to doses of up to 1.8–2 [[Sievert|Sv]] (180–200 rem).<ref>{{cite web|url=http://www.johnstonsarchive.net/nuclear/radevents/1960USSR1.html|title=K-8 submarine reactor accident, 1960|date=2004-06-10|work=Database of radiological incidents and related events – Johnston's Archive|access-date=2007-06-17}}</ref>
|-
|January 3, 1961
|[[National Reactor Testing Station]], [[Idaho]], US
|Accidental criticality, steam explosion, 3 fatalities, release of fission products
|[[File:US AEC SL-1.JPG|thumb|right|333px|[[SL-1]] reactor being removed from the [[National Reactor Testing Station]].]]{{Further|SL-1#Accident_and_response}}During a maintenance shutdown, the [[SL-1]] experimental nuclear reactor underwent a [[prompt critical]] reaction causing core materials to explosively vaporize. [[Water hammer]] estimated at {{convert|10000|psi}} struck the top of the reactor vessel propelling the entire reactor vessel upwards over {{convert|9|ft}} in the air. One operator who had been standing on top of the vessel was killed when a shield plug impaled him and lodged in the ceiling. Two other military personnel were also killed from the trauma of the explosion, one of which had removed the central control rod too far. The plant had to be dismantled and the contamination was buried permanently nearby. Most of the release of radioactive materials was concentrated within the reactor building.
|-
|January 24, 1961
|[[Goldsboro, North Carolina]], US
|Physical destruction of a nuclear bomb, loss of nuclear materials
|{{Main|1961 Goldsboro B-52 crash}}
A USAF [[Boeing B-52 Stratofortress|B-52]] [[bomber aircraft|bomber]] caught fire and exploded in midair due to a major leak in a wing fuel cell {{convert|12|mi}} north of [[Seymour Johnson Air Force Base]], [[North Carolina]]. Five crewmen [[parachute]]d to safety, but three others died&mdash;two in the aircraft and one on landing. The incident released the bomber's two [[Mark 39 nuclear bomb]]s. Three of the four arming devices on one of the bombs activated, causing it to carry out many of the steps needed to arm itself, such as the charging of the firing [[capacitor]]s and, critically, the deployment of a {{convert|100|ft|adj=on}} diameter [[Retarded bomb|retardation parachute]]. The parachute allowed the bomb to hit the ground with little damage. The fourth arming device—the pilot's safe/arm switch—was not activated, preventing detonation. The second bomb plunged into a muddy field at around {{convert|700|mph|m/s|abbr=on|sigfig=1}} and disintegrated. Its tail was discovered about {{convert|20|ft|sigfig=1}} down and much of the bomb recovered, including the [[tritium]] bottle and the [[plutonium]]. However, excavation was abandoned due to uncontrollable ground water flooding. Most of the [[thermonuclear]] stage, containing [[uranium]], was left on site. It is estimated to lie around {{convert|55|ft}} below ground. The [[United States Air Force|Air Force]] purchased the land and fenced it off to prevent its disturbance, and it is tested regularly for contamination, although none has so far been found.<ref>{{cite web|url=http://www.ibiblio.org/bomb/|title=Broken Arrow: Goldsboro, NC|date=2000-12-04|access-date=2007-06-17}}</ref>
|-
|March 14, 1961
|[[Yuba City, California]], US
|Physical destruction of a nuclear bomb, loss of nuclear materials
|{{Main|1961 Yuba City B-52 crash}}
USAF [[Boeing B-52 Stratofortress|B-52]] [[bomber aircraft|bomber]] departed [[Mather Air Force Base]], California and experienced a [[uncontrolled decompression|decompression event]] that required it to fly below 10,000 feet.  Resulting increased fuel consumption led to fuel exhaustion; the aircraft crashed near [[Yuba City, California]] with two nuclear bombs, which did not trigger a nuclear explosion.
|-
|July 4, 1961
|Coast of [[Norway]] 
|Near meltdown
|The [[Soviet Navy|Soviet]] {{sclass2|Hotel|submarine|0}} submarine {{ship|Soviet submarine|K-19||2}} suffered a failure in its cooling system. Reactor core temperatures reached {{convert|800|C|sigfig=2}}, nearly enough to melt the fuel rods, although the crew was able to regain temperature control by using emergency procedures. The incident contaminated parts of the ship, some of the onboard ballistic missiles and the crew, resulting in several fatalities.  The film ''[[K-19: The Widowmaker]]'', starring [[Harrison Ford]] and [[Liam Neeson]], {{cn-span|text=offers a controversially fictionalized story of these events.|date=July 2021}}
|-
|May 1, 1962 
|[[Sahara]] desert, [[French Algeria]] (now [[Algeria]])
|Accidental venting of underground nuclear test
|The second French underground nuclear test, codenamed [[Béryl incident|Béryl]], took place in a shaft under Mount Taourirt, near [[In Ecker]], {{cvt|150|km|mi}} north of [[Tamanrasset]], Algerian [[Sahara]]. Due to improper sealing of the shaft, a spectacular flame burst through the concrete cap and radioactive gases and dust were vented into the atmosphere. The plume climbed up to {{cvt|2600|m|ft}} high and radiation was detected hundreds of kilometers away. About a hundred soldiers and officials, including two ministers, were irradiated. The number of contaminated Algerians is unknown.
|-
|May 22, 1962 
|[[Chico, California]], US
|Explosion of [[HGM-25A Titan I|Titan I ICBM]] 
|A [[HGM-25A Titan I|Titan I ICBM]] exploded in its silo in Chico, California.<ref>{{Cite web|url=http://www.themilitarystandard.com/missile/titan1/beale_afb.php|title=Titan I at Beale AFB, California|website=www.themilitarystandard.com}}</ref> During a contractor checkout, a leak and subsequent explosion occurred at launcher 1 at complex 4C at Chico, destroying a Titan I and causing heavy damage to the silo. The Air Force concluded that the two separate explosions occurred because of a blocked vent and blocked valve.  All contractors and crew of the silo escaped unharmed.
|-
|June 20, 1962
|Johnson Island
|Self-destruction of nuclear-armed Thor missile
|Part of the Starfish test series by the US military, a Thor missile was launched but had its flight aborted one minute after its takeoff. No nuclear explosion took place. However, heavily contaminated missile components fell back down upon the island where service personnel worked and lived. 
|-https://nautilus.org/apsnet/cleaning-up-johnston-atoll/
|-
|July 25, 1962
|Johnson Island
|Explosion of nuclear-armed Thor missile
|A Thor missile exploded on its launchpad, scattering highly contaminated debris all over the island. Service personnel were heavily exposed to radiation both during the explosion and in subsequent emergency clean-up efforts. Veterans who were exposed to the high radiological hazards all suffered lethal long-term effects of radiation-based cancers.
|-https://nautilus.org/apsnet/cleaning-up-johnston-atoll/
|- 
|April 10, 1963 
|
|Loss of nuclear reactor
|The submarine {{USS|Thresher|SSN-593|6}} sank about {{convert|190|nmi|mi km|abbr=on}} east of [[Cape Cod]], [[Massachusetts]] due to improper welds allowing in seawater which forced a shutdown of the reactor. Poor design of its emergency blow system prevented the ship from surfacing and the disabled ship ultimately descended to [[crush depth]] and [[implosion (mechanical process)|imploded]], killing all 129 on board. Wreckage remains on the sea floor  at  8,400 feet (2,600 m) below the surface
|-
|January 13, 1964
|[[Salisbury, Pennsylvania]] and [[Frostburg, Maryland]], US
|Accidental loss and recovery of thermonuclear bombs
|{{Main|1964 Savage Mountain B-52 crash}}
A USAF B-52 on airborne alert duty encountered a severe winter storm and extreme turbulence, ultimately disintegrating in midair over South Central Pennsylvania.<ref>{{cite web|url=http://www.salisburypa.com/buzzonefour.html|title=Cold War Mission Ended In Tragedy for B-52 Crew|access-date=2008-05-26|archive-url=https://web.archive.org/web/20181130005736/http://www.salisburypa.com/buzzonefour.html|archive-date=2018-11-30|url-status=dead}}</ref> Only the two pilots survived. One crew member failed to bail out and the rest succumbed to injuries or exposure to the harsh winter weather. A search for the missing weapons was initiated, and recovery was effected from portions of the wreckage at a farm northwest of Frostburg, MD.
|-
|December 5, 1964
|[[Ellsworth AFB]], [[South Dakota]]
|[[LGM-30 Minuteman|Minuteman ICBM]] missile warhead separation
|The warhead separated in the launch tube due to an electrical short circuit and fell to the bottom of the tube, at launch facility Lima-02 near [[Vale, South Dakota]]. The missile site was part of the former [[44th Missile Wing]] at [[Ellsworth AFB]], South Dakota.<ref>{{cite web|url=http://rapidcityjournal.com/news/local/article_92b6722d-9cd5-5551-8831-f61964da70b2.html|title=South Dakota's secret nuclear missile accident revealed|last=staff|first=Seth Tupper Journal|website=rapidcityjournal.com|date=3 November 2017 |access-date=13 April 2018}}</ref>
|-
|December 8, 1964 
|[[Grissom Joint Air Reserve Base|Bunker Hill Air Force Base]], [[Indiana]], US 
|Fire, radioactive contamination
|A USAF [[Convair B-58 Hustler|B-58]] aircraft carrying a [[B53 nuclear bomb]] internally, and four [[B43 nuclear bomb]]s externally, caught fire while taxiing after its landing gear collapsed. The B53 burned, causing contamination of the crash area. Two of the B43s caused some plutonium and uranium contamination.<ref name="AFRRI" /><ref>{{cite web|author=Mason & Hanger - Silas Mason Co. Inc.|title=Broken Arrow Examination|page=13-38 of PDF|date=16 February 1965|url=https://www.governmentattic.org/40docs/NNSApost1980BrokenArrow_2021.pdf|publisher=Government Attic}}</ref> One of the B43 bombs was crushed between the plane's collapsed wing and a snowbank while the plane burned, causing a "unique and previously unevaluated situation" in which a nuclear weapon was made to experience "extreme cold, crushing impact, and intense heat simultaneously."<ref>{{cite web|last1=Mora|first1=Carl|last2=Taylor|first2=John|last3=Ullrich|first3=Rebecca|title=A History of Exceptional Service in the National Interest (SAND97-1029)|publisher=Sandia National Laboratories|date=1997|url=https://www.sandia.gov/app/uploads/sites/194/2022/01/JohnsonExceptionalServiceInTheNationalInterest971029.pdf|pp=143}}</ref>
|-
|January 1965
|[[Livermore, California]], US
|Release of nuclear materials
|An accident at [[Lawrence Livermore National Laboratory]] released 300&nbsp;kCi (11 PBq) of [[tritium]] gas. Subsequent study found this release was not likely to produce adverse health effects in the surrounding communities.<ref>{{cite web|url=http://www.atsdr.cdc.gov/HAC/PHA/livermore1/lnl_p1.html|archive-url=https://web.archive.org/web/20020110103643/http://www.atsdr.cdc.gov/HAC/PHA/livermore1/lnl_p1.html|url-status=dead|archive-date=January 10, 2002|title=ATSDR – Health Consultation – Lawrence Livermore National Laboratory (U.S. DOE), Livermore, Alameda County, California|date=2009-11-30|publisher=Atsdr.cdc.gov|access-date=2010-01-27}}</ref>
|-
|October 11, 1965
|Rocky Flats Plant, Golden, Colorado, US
|Fire, exposure of workers
|{{Further|Radioactive contamination from the Rocky Flats Plant}}A fire at Rocky Flats exposed a crew of 25 to up to 17 times the legal limit for radiation.
|-
|December 5, 1965 
|[[Philippine Sea]]
|Loss of a nuclear bomb
|{{Main|1965 Philippine Sea A-4 incident}}
A [[U.S. Navy]] [[A-4 Skyhawk|A-4E Skyhawk]] aircraft with one [[B43 nuclear bomb]] on board fell off the [[aircraft carrier]] {{USS|Ticonderoga|CV 14|6}} into {{convert|16200|ft}} of water while the ship was underway from [[Vietnam]] to [[Yokosuka (city)|Yokosuka]], Japan. The plane, pilot and weapon were never recovered. There is dispute over exactly where the incident took place&mdash;the [[United States Department of Defense|U.S. Defense Department]] originally stated it took place {{convert|500|mi}} off the coast of Japan; The accident was said to occur {{convert|68|mi|nmi km}} from [[Kikai Island]], [[Kagoshima Prefecture]], [[Japan]].<ref name="amami2015">{{cite book |author=Maruyama Kuniaki 丸山邦明 |chapter=Gunji kichi mondai to Amami |script-chapter=ja:軍事基地問題と奄美 |title=Amami sengo-shi |script-title=ja:奄美戦後史 |editor=Kagoshima-ken chihō jichi kenkyūsho 鹿児島県地方自治研究所 |year=2005 |language=ja |page=254}}</ref>
U.S. Navy documents later show it happened about {{convert|80|mi}} from the [[Ryukyu Islands]] and {{convert|200|mi}} from [[Okinawa Prefecture|Okinawa]].<ref>{{cite news|url=http://www.cnn.com/SPECIALS/cold.war/experience/the.bomb/broken.arrows/content/1960e.html |title=Cold War: Broken Arrows (1960e) |access-date=2007-06-17 |archive-url=https://web.archive.org/web/20070327211540/http://www.cnn.com/SPECIALS/cold.war/experience/the.bomb/broken.arrows/content/1960e.html |archive-date=2007-03-27 |work=[[CNN]] |year=1998}}</ref> 

|-
|January 17, 1966 
|[[Palomares, Almería]], Spain
|Accidental destruction, loss and recovery of nuclear bombs
|{{Main|1966 Palomares B-52 crash}}
A [[United States Air Force|USAF]] B-52 carrying four hydrogen bombs collided with a USAF [[KC-135]] [[tanker aircraft|jet tanker]] during over-ocean [[in-flight refueling]]. Four of the B-52's seven crew members parachuted to safety while the remaining three were killed along with all four of the KC-135's crew. The conventional explosives in two of the bombs detonated upon impact with the ground, dispersing plutonium over nearby farms. A third bomb landed intact near [[Palomares, Almería]] (Spain) while the fourth fell {{convert|12|mi}} off the coast into the Mediterranean sea. The U.S. Navy conducted a three-month search involving 12,000 men and successfully recovered the fourth bomb. The U.S. Navy employed the use of the deep-diving research submarine {{ship|DSV|Alvin}} to aid in the recovery efforts. During the ensuing cleanup, {{convert|1500|t|ST|lk=on}} of radioactive soil and tomato plants were shipped to a nuclear dump in [[Aiken, South Carolina]]. The U.S. settled claims by 522 Palomares residents for [[United States dollar|$]]600,000. The town also received a $200,000 [[desalinization]] plant. The motion picture ''[[Men of Honor]]'' (2000), starring [[Cuba Gooding, Jr.]], as [[United States Navy|USN]] Diver, Master Chief Petty Officer Carl Brashear, and [[Robert De Niro]] as USN Diver, Chief Petty Officer Billy Sunday, contained an account of the fourth bomb's recovery.<ref>{{cite web|url=http://www.iht.com/articles/2008/09/11/europe/journal.php|title=Spanish town still haunted by its brush with Armageddon|url-status=dead|archive-url=https://web.archive.org/web/20080914002703/http://iht.com/articles/2008/09/11/europe/journal.php|archive-date=2008-09-14|access-date=2008-09-13}}</ref>
|-
|January 21, 1968
|[[Thule Air Base]], Greenland
|Loss and partial recovery of nuclear bombs
|{{Main|1968 Thule Air Base B-52 crash}}
A fire broke out in the [[navigator]]'s compartment of a USAF [[Boeing B-52 Stratofortress|B-52]] near Thule Air Base, Greenland. The bomber crashed {{convert|7|mi}} from the airbase, rupturing the bomber's bomb bay and causing the conventional explosives in the four [[B28 nuclear bomb|B28FI thermonuclear bombs]] to detonate, fragmenting and spreading the [[Nuclear weapon design|radioactive primary and secondary components]] across a large area. The burning bomber and its fuel load melted through the ice, dropping wreckage to the seafloor underneath.  The recovery and decontamination effort was complicated by Greenland's harsh weather. Contaminated ice and debris were returned and buried in the United States. Recovered bomb fragments were recycled by [[Pantex]], in [[Amarillo, Texas]]. The incident caused outrage and protests in [[Denmark]], as Greenland is a Danish possession, and Denmark forbade nuclear weapons on its territory.
|-
|March 8, 1968
||1,560 nautical miles (2,890 km) northwest of Oahu in the Pacific Ocean
|?
|The Soviet nuclear submarine {{ship|Soviet submarine|K-129|1960|2}} sank with a crew of 98 due to an explosion of unknown cause. The International Atomic Energy Agency stated that two nuclear warheads from K-129 were located in the Pacific 1,230 miles from Kamchatka at coordinates 40°6'N and 179°57'E at a depth of 6,000 metres (20,000 ft), and lists them as recovered.
|-
|May 22, 1968 
|740&nbsp;km (400 nmi) southwest of the [[Azores]]
|Loss of nuclear reactor and two [[W34 (nuclear warhead)|W34]] nuclear warheads
|[[File:Mark 45 Nuclear Torpedo.jpg|thumb|Mark 45 nuclear torpedo, similar to the two that were lost]]The [[United States Navy|U.S.]] [[submarine]] {{USS|Scorpion|SSN-589|6}} sank while en route from [[Rota, Spain|Rota]], Spain, to [[Norfolk Naval Base|Norfolk]], [[Commonwealth of Virginia|Virginia]], United States. All 99 officers and men on board were killed, and while the cause of the sinking remains unknown, Scorpion's originally planned full overhaul was reduced in scope, and long-overdue SUBSAFE work, such as a new central valve control system, was not performed {{citation needed|date=January 2025}}. The wreckage of the submarine, its [[S5W reactor|S5W]] [[nuclear reactor]], and its two [[Mark 45 torpedo|Mark 45]] torpedoes with [[W34 (nuclear warhead)|W34]] nuclear warheads, remain on the sea floor in more than {{cvt|3000|m|ft}} of water.
|-
|May 24, 1968
||[[Barents Sea]], Arctic Ocean 
|Loss of cooling, radioactive contamination, nuclear fuel damaged
|During sea trials, the Soviet nuclear submarine {{ship|Soviet submarine|K-27||2}} (Project 645) suffered severe problems with its reactor cooling systems. After spending some time at reduced power, reactor output inexplicably dropped and sensors detected an increase of [[gamma ray|gamma radiation]] in the reactor compartment to 150 [[rad (unit)|rad]]/h. The safety buffer tank released radioactive gases further contaminating the submarine. The crew shut the reactor down and subsequent investigation found that approximately 20% of the fuel assemblies were damaged. The entire submarine was scuttled in the [[Kara Sea]] in 1981.
|-
|August 27, 1968
|[[Severodvinsk]], Russia (then [[USSR]])
|Reactor power excursion, contamination
|While in the naval yards at Severodvinsk for repairs, the Soviet {{sclass2|Yankee|submarine|0}} [[nuclear submarine]] {{ship|Soviet submarine|K-140||2}} suffered an uncontrolled increase of the reactor's power output. One of the reactors activated automatically when workers raised control rods to a higher position and power increased to 18 times normal, while pressure and temperature levels in the reactor increased to four times normal. The accident also increased radiation levels aboard the vessel. The problem was traced to the incorrect installation of control rod electrical cables.
|-
|May 11, 1969
|Rocky Flats Plant, Golden, Colorado, US
|Plutonium fire, contamination
|{{Further|Radioactive contamination from the Rocky Flats Plant#1969 fire}}An accident in which 5&nbsp;kilograms of plutonium burnt inside a [[glovebox]] at Rocky Flats. Cleanup took two years and was the costliest industrial accident ever to occur in the United States at that time.<ref>{{cite web
 |last=Snider 
 |first=Laura 
 |title=Looking back on Mother's Day fire at Rocky Flats 
 |work=Boulder & County News 
 |publisher=[[Boulder Daily Camera]] 
 |date=2009-05-10 
 |url=http://www.dailycamera.com/news/2009/may/10/rocky-flats-1969-fire-plutonium-denver-boulder/ 
 |quote=On Mother's Day in 1969... the worst industrial conflagration the country had ever seen... when Building 776–777 on the Rocky Flats campus eight miles south of Boulder caught fire... 
 |access-date=2009-07-26 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20090512111428/http://www.dailycamera.com/news/2009/may/10/rocky-flats-1969-fire-plutonium-denver-boulder/ 
 |archive-date=May 12, 2009 
}}</ref><ref>{{cite web
 |last=Greenlee 
 |first=Robert 
 |title=Rocky Flats Colorado Nuclear Weapons Production Facility 1952–1988 
 |work=ME 360L – Mechanical Engineering Design III 
 |publisher=[[University of New Mexico]] 
 |date=2008-04-24 
 |url=http://www.unm.edu/~bgreen/ME360/Rocky%20Flats%20Colorado.pdf 
 |quote=1969 Fire ... * Most costly industrial accident in US * 2 years to clean up 
 |access-date=2009-07-26 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20120929074854/http://www.unm.edu/~bgreen/ME360/Rocky%20Flats%20Colorado.pdf 
 |archive-date=September 29, 2012 
}}</ref><ref>{{cite web
 |last=Moore 
 |first=LeRoy 
 |title=Guilt or innocence at Rocky Flats 
 |work=NUCLEAR NEXUS » Local Hazards » Rocky Flats 
 |publisher=Rocky Mountain Peace and Justice Center 
 |date=January 2006 
 |url=http://www.rmpjc.org/system/files/RF%2Bcase%2Bto%2Bjury_Moore%2B1-06.pdf 
 |quote=A fire at Rocky Flats on Mother's Day, May 11, 1969, turned out to be the worst industrial fire to date in US history. 
 |access-date=2009-07-26 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20080821113933/http://www.rmpjc.org/system/files/RF%2Bcase%2Bto%2Bjury_Moore%2B1-06.pdf 
 |archive-date=August 21, 2008 
}}</ref>
|}

==1970s==
{| class="wikitable toptextcells"
|+
!Date
!Location
!Type
!Description
|-
|April 12, 1970
|[[Bay of Biscay]]
|Loss of a nuclear submarine
|The Soviet {{sclass2|November|submarine|0}} [[attack submarine]] {{ship|Soviet submarine|K-8||2}} sank during salvage with 52 sailors on board after suffering fires in two compartments simultaneously. Both reactors were shut down. The crew attempted to hook a tow line to a [[People's Republic of Bulgaria|Bulgarian]] [[merchant marine|merchant vessel]], but ultimately failed.<ref>{{cite news |work=CNN |title=Cold War: Broken Arrows (1970a)| url = http://www.cnn.com/SPECIALS/cold.war/experience/the.bomb/broken.arrows/content/1970a.html |year=1998 |access-date=2007-06-17 |archive-url = https://web.archive.org/web/20070330225510/http://www.cnn.com/SPECIALS/cold.war/experience/the.bomb/broken.arrows/content/1970a.html <!-- Bot retrieved archive --> |archive-date = 2007-03-30}}</ref>
|-
|December 18, 1970
|[[Nevada Test Site]]
|Accidental venting of nuclear explosion
|[[File:Operation Emery - Baneberry.jpg|thumb|Baneberry's radioactive plume rises from a shock fissure. Contaminants were carried in three different directions by the wind.]]The [[Partial Nuclear Test Ban Treaty]] of 1963 was meant to prevent the nuclear fallout freely associated with the earlier above ground tests. Some venting might still happen on site, but the 1970 "Baneberry" test blast &ndash; part of [[Operation Emery]] &ndash; resulted in extensive off-site fallout. The 10-kiloton  "Baneberry" test took place under [[Area 8 (Nevada National Security Site)|Area 8]] on [[Yucca Flat]]. The weapon detonated as planned at the bottom of a sealed vertical shaft {{cvt|900|ft|m}} below the Earth's surface, but the device's energy cracked the soil in unexpected ways, causing a fissure near ground zero and releasing a plume of hot gases and radioactive dust that continued for many hours, raining fallout on workers within NTS.<ref>{{Cite web |url=https://asc.llnl.gov/news/news_archive/baneberry.pdf |title=Lawrence Livermore National Laboratory. News Archive. Tarabay H. Antoun. ''Three Dimensional Simulation of the Baneberry Nuclear Event'' |access-date=2008-07-11 |archive-date=2010-05-27 |archive-url=https://web.archive.org/web/20100527170837/https://asc.llnl.gov/news/news_archive/baneberry.pdf |url-status=dead }}</ref><ref>{{cite web |url=http://digital.library.unlv.edu/cdm4/item_viewer.php?CISOROOT=/nts&CISOPTR=1283 |title=University of Las Vegas. Nevada Test Site Oral History Project. ''Clifford Olsen'' (interviewed September 20, 2004) |publisher=Digital.library.unlv.edu |access-date=2010-01-27 |archive-url=https://web.archive.org/web/20080801214838/http://digital.library.unlv.edu/cdm4/item_viewer.php?CISOROOT=%2Fnts&CISOPTR=1283 |archive-date=August 1, 2008 |url-status=dead }}</ref> Six percent of the explosion's radioactive products were vented, releasing 6.7 MCi of radioactive material, including 80 kCi of [[Iodine-131]] and a high ratio of noble gases.<ref>{{cite journal|url=http://www.cancer.gov/i131/fallout/Chapter2.pdf|journal=[[National Cancer Institute]]|at=Chapter 2|title=Estimated Exposures and Thyroid Doses Received by the American People from Iodine-131 in Fallout Following Nevada Atmospheric Nuclear Bomb Tests: History of the Nevada Test Site and Nuclear Testing Background|date=September 1997|id=[[National Institute of Health|NIH]] 97-4264|access-date=2008-07-11|archive-date=2010-12-21|archive-url=https://web.archive.org/web/20101221175816/http://www.cancer.gov/i131/fallout/Chapter2.pdf|url-status=dead}}</ref> The hot cloud's lighter particles were carried to three altitudes by three diverging [[jet stream]] layers and conveyed by winter storms and the jet stream to be deposited heavily as [[radionuclide]]-laden snow in [[Lassen County, California|Lassen]] and [[Sierra County, California|Sierra]] counties in northeast California, and to lesser degrees in northern [[Nevada]], southern Idaho and some eastern sections of [[Oregon]] and Washington states.<ref>{{cite web|url=http://www.260press.com/gallery-33.htm |title=Two-Sixty Press. Richard L. Miller. Fallout Maps. ''Gallery 33'' |publisher=260press.com |access-date=2010-01-27}}</ref> The three diverging jet stream layers conducted radionuclides across the U.S. to Canada, the [[Gulf of Mexico]] and the Atlantic Ocean. Some 86 workers at the site were exposed to radioactivity, but according to the [[United States Department of Energy|Department of Energy]], none received a dose exceeding site guidelines and, similarly, radiation drifting offsite was not considered to pose a hazard by the DOE.<ref>{{cite web |url=http://www.brookings.edu/projects/archive/nucweapons/nts.aspx |archive-url=https://web.archive.org/web/20081110112057/http://www.brookings.edu/projects/archive/nucweapons/nts.aspx |url-status=dead |archive-date=2008-11-10 |title=Nuclear testing at the Nevada Test Site |work=Brookings }}</ref> In March 2009, ''TIME'' magazine identified the Baneberry Test as one of the world's worst nuclear disasters.<ref>{{cite web|url=https://content.time.com/time/photogallery/0,29307,1887705,00.html|title=The Worst Nuclear Disasters – Photo Essays|website=[[Time (magazine)|Time]]|access-date=13 April 2018}}</ref>
|-
|December 12, 1971
|[[New London, Connecticut]], US
|Spill of irradiated water
|During the transfer of radioactive coolant water from the submarine {{USS|Dace|SSN-607|6}} to the [[submarine tender]] {{USS|Fulton|AS-11|6}} {{convert|500|usgal}} were spilled into the [[Thames River (Connecticut)|Thames River]] (US).
|-
|December 1972
|[[Pawling (village), New York|Pawling, New York]], US
|Contamination
|A major fire and two explosions contaminated the plant and grounds of a plutonium fabrication facility resulting in a permanent shutdown.<ref>{{cite web|url=https://lucian.uchicago.edu/blogs/atomicage/2014/08/13/dateline-blast-in-72-fueled-fears-about-nuclear-lake-via-poughkeepsie/|title=Dateline: Blast in '72 fueled fears about Nuclear Lake via Poughkeepsie|access-date=17 January 2021}}</ref><ref>{{cite web|url=https://www.nrc.gov/docs/ML0037/ML003703553.pdf|title=NRC Releases Site in Pawling, NY for Unrestricted Use – 19 July 1994|access-date=17 January 2021}}</ref>
|-
|April 21, 1973
|[[Pacific Ocean]], 370 miles from [[Puget Sound]] 
|Primary coolant leak
|[[Nuclear reactor coolant|The primary coolant]] leaked on board the submarine {{USS|Guardfish|SSN-612|6}} while underway<ref>{{Cite web|url=https://www.upi.com/Archives/1989/05/29/Report-Nuclear-sub-suffers-accident-off-Oregon-in-1973/5351612417600/|title = Report: Nuclear sub suffers accident off Oregon in 1973}}</ref> 
|-
|1975
|Location unknown
|Contamination
|Radioactive resin contaminated the [[United States Navy|American]] {{sclass|Sturgeon|submarine|1}} {{USS|Guardfish|SSN-612|6}} after the wind unexpectedly blew the powder back towards the ship. The resin is used to remove dissolved radioactive minerals and particles from the primary coolant loops of submarines. This type of accident was fairly common; however, U.S. Navy nuclear vessels no longer discharge resin at sea.{{citation needed|date=December 2018}}
|-
|October 1975
|[[Apra Harbor]], [[Guam]]
|Spill of irradiated water
|While disabled, the submarine tender {{USS|Proteus|AS-19|6}} discharged radioactive coolant water. A [[Geiger counter]] at two of the harbor's public beaches showed 100 [[millirem]]s/hour, fifty times the allowable dose.<ref>{{cite book |last=Jamadhagni |first=S Utham Kumar |date=2014 |title= The Unrecognised Peril: Threats to Environmental Security |url= https://books.google.com/books?id=1weqCQAAQBAJ&q=USS+Proteus+radioactive+coolant+water&pg=PA265|publisher= Vij Books India Pvt Ltd|page= 265 |isbn= 978-9382652502}}</ref><ref name="Kaplan1983">{{cite journal |last=Kaplan |first=David B. |date=August 1983 |title=When Incidents are Accidents, The Silent Saga of the Nuclear Navy |url=http://oc.itgo.com/kitsap/nuclear/clymer.htm |journal=Oceans Magazine |access-date=2016-09-11 |archive-url=https://web.archive.org/web/20190827200112/http://oc.itgo.com/kitsap/nuclear/clymer.htm |archive-date=2019-08-27 |url-status=dead }}</ref>
|-
|August 1976
|[[Benton County, Washington]], United States
|Explosion, contamination of worker
|An explosion at the [[Hanford site]] Plutonium Finishing Plant blew out a quarter-inch-thick lead glass window. [[Harold McCluskey]], a worker, was showered with [[nitric acid]] and radioactive glass. He inhaled the largest dose of [[Americium-241|<sup>241</sup>Am]] ever recorded, about 500 times the U.S. government occupational standards. The worker was placed in isolation for five months and given an experimental drug to flush the isotope from his body. By 1977, his body's radiation count had fallen by about 80 percent. He died of natural causes in 1987 at age 75.<ref>{{cite news|author=AP wire |title=Hanford nuclear workers enter site of worst contamination accident |url=http://www.billingsgazette.com/index.php?id=1&display=rednews/2005/06/03/build/nation/94-contamination.inc |date=2005-06-03 |access-date=2007-06-17 |url-status=dead |archive-url=https://web.archive.org/web/20051222173316/http://www.billingsgazette.com/index.php?id=1 |archive-date=2005-12-22 }}</ref>
|-
|1977
|Coast of [[Kamchatka Peninsula|Kamchatka]]
|Loss and recovery of a nuclear warhead
|The [[Soviet Navy|Soviet]] [[Nuclear submarine|submarine]] {{ship|Soviet submarine|K-171||2}} accidentally released a nuclear warhead. The warhead was recovered after a search involving dozens of ships and aircraft.<ref>{{cite news |title=Cold War: Broken Arrows (1970d) |url=http://www.cnn.com/SPECIALS/cold.war/experience/the.bomb/broken.arrows/content/1970d.html |work=[[CNN]] |year=1998 |access-date = 2007-06-17 |archive-url=https://web.archive.org/web/20070602203629/http://www.cnn.com/SPECIALS/cold.war/experience/the.bomb/broken.arrows/content/1970d.html |archive-date = 2007-06-02}}</ref>
|-
|January 24, 1978
|[[Northwest Territories]], Canada
|Spill of nuclear fuel
|[[Kosmos 954]], a Soviet [[RORSAT|Radar Ocean Reconnaissance Satellite]] with an onboard nuclear reactor, failed to separate from its booster and broke up on reentry over [[Western Canada|Western]] and Northern Canada. The fuel was spread over a wide area and some radioactive pieces were recovered. The Soviet Union eventually paid the [[Government of Canada|Canadian government]] $3 million [[Canadian dollar|CAD]] (${{inflation|CA|3|1978}} million today) for expenses relating to the crash.
|-
|May 22, 1978
|Near [[Puget Sound]], [[Washington (state)|Washington]], United States
|Spill of irradiated water
|A valve was mistakenly opened aboard the submarine {{USS|Puffer|SSN-652|6}} releasing up to {{convert|500|usgal}} of radioactive water.<ref name="Kaplan1983" />
|}

==1980s==
{| class="wikitable toptextcells"
|+
!Date
!Location
!Type
!Description
|-
|September 18, 1980
|[[Little Rock Air Force Base|Little Rock AFB]], [[Arkansas]]
|Nuclear missile fuel explosion
|{{Main|1980 Damascus Titan missile explosion}}
At about 6:30&nbsp;p.m., an airman conducting maintenance on a USAF [[LGM-25C Titan II|Titan-II]] missile at [[Little Rock Air Force Base]]'s Launch Complex 374-7 in [[Southside, Van Buren County, Arkansas|Southside]] ([[Van Buren County, Arkansas|Van Buren County]]), just north of [[Damascus, Arkansas]], dropped a {{convert|9|lb|adj=on|spell=in|0}} [[socket wrench|socket]] from a socket wrench, which fell about {{convert|80|ft}} before hitting and piercing the skin on the rocket's first-stage fuel tank, causing it to leak. The area was evacuated.  Overnight, at about 3:00 [[12-hour clock|a.m.]], the [[hypergolic]] fuel exploded. The [[B53 nuclear bomb|W53]] warhead landed about {{convert|100|ft}} from the launch complex's entry gate; its safety features operated correctly and prevented any explosion, chemical or nuclear. An Air Force airman, David Livingston, was killed and the launch complex was destroyed.<ref>{{cite web | title = Titan Missile Explosion | url = http://www.encyclopediaofarkansas.net/encyclopedia/entry-detail.aspx?entryID=2543}}</ref>
|-
|February 1982 to December 1989
|[[Kola Peninsula]], Russia (former USSR)
|Release of nuclear materials
|The [[Andreev Bay nuclear accident]] was associated with leaks in a massive cooling and storage pool.  The leaks caused about 700,000 tonnes of highly radioactive water to leak into the Barents Sea during that time period. During the extensive period of attempted repairs and subsequent dismantling of the pool, other incidents occurred on site, including accidental accumulations of critical masses of material releasing radiation and an "industrial accident" that caused two cleanup workers to plunge directly into the radioactive pool.
|-
|August 8, 1982
|[[Barents Sea]]
|Release of nuclear materials
|While on duty in the Barents Sea, there was a release of liquid metal coolant from the reactor of the Soviet Project 705 {{sclass2|Alfa|submarine|1}} {{ship|Soviet submarine|K-123||2}}. The accident was caused by a leak in the steam generator. Approximately two tons of metal alloy leaked into the reactor compartment, irreparably damaging the reactor so it had to be replaced. It took nine years to repair the submarine.
|-
|January 3, 1983
|South Atlantic
|Contamination
|The Soviet nuclear-powered spy satellite [[Kosmos 1402]] burned up over the South Atlantic.
|-
|August 10, 1985
|[[Chazhma Bay]], [[Vladivostok]]
|Release of nuclear materials
|About {{convert|35|mi}} from Vladivostok in Chazhma Bay, the [[Soviet Navy|Soviet]] {{sclass2|Echo|submarine|0}} [[Nuclear submarine|submarine]] {{ship|Soviet submarine|K-431||2}} suffered a reactor explosion, producing fatally high levels of radiation. Ten men were killed, but the deadly cloud of radioactivity did not reach [[Vladivostok]].<ref>{{cite news |title=Cold War: Broken Arrows (1980b)| url = http://www.cnn.com/SPECIALS/cold.war/experience/the.bomb/broken.arrows/content/1980b.html |work=CNN | year = 1998 | access-date = 2007-06-17 |archive-url = https://web.archive.org/web/20070328010005/http://www.cnn.com/SPECIALS/cold.war/experience/the.bomb/broken.arrows/content/1980b.html |archive-date = 2007-03-28}}</ref>
|-
|1986
|[[Hanford Site]], Washington, US
|Release of nuclear materials
|The U.S. government declassified 19,000 pages of documents indicating that between 1946 and 1986, the Hanford Site near [[Richland, Washington]], released thousands of [[U.S. liquid gallon|US gallons]] of radioactive liquids. Many of the people living in the affected area received low doses of radiation from [[Iodine-131|<sup>131</sup>I]].
|-
|October 3, 1986
|North Atlantic
|Loss of two nuclear reactors and either 32 or 48 warheads<ref>{{cite book|date=2003|url=https://books.google.com/books?id=73_zmsMEpLcC&pg=RA1-PA130 |page=131 |title=Prisoners of the Nuclear Dream|editor-first1=M V |editor-last1=Ramana |editor-first2=C |editor-last2=Rammanohar Reddy |isbn=978-8125024774 |publisher=Orient Blackswan}}</ref><ref>{{cite web|last=Wade |first=Mark |title=R-27U |url=http://www.astronautix.com/r/r-27u.html |archive-url=https://web.archive.org/web/20161228044247/http://astronautix.com/r/r-27u.html |url-status=dead |archive-date=December 28, 2016 |access-date=5 May 2020}}</ref><ref>{{cite web|title=667A YANKEE I |url=https://fas.org/nuke/guide/russia/slbm/667A.htm|access-date=5 May 2020}}</ref>{{refn|group=nb|The missiles involved in the accident must have been the R-27U version as the original version was retired by 1983. Sources given conflicting numbers on the number of warheads carried by the R-27U, either two or three.}}
|{{convert|480|mi}} east of [[Bermuda]], the Soviet {{sclass2|Yankee I|submarine|0}} [[Ballistic missile submarine|submarine]] {{ship|Soviet submarine|K-219||2}} experienced an explosion in one of its missile tubes and at least three crew members were killed. Sixteen nuclear missiles and two reactors were on board. [[General Secretary of the Communist Party of the Soviet Union|Soviet leader]] [[Mikhail Gorbachev]] privately communicated news of the disaster to U.S. President [[Ronald Reagan]] before publicly acknowledging the incident on October 4. Two days later, on October 6, the submarine sank in the Atlantic Ocean while under tow in {{convert|18000|ft}} of water.<ref>{{cite news | title = Cold War: Broken Arrows (1980c)| url = http://www.cnn.com/SPECIALS/cold.war/experience/the.bomb/broken.arrows/content/1980c.html | work=CNN | year = 1998 | access-date = 2007-06-17 |archive-url = https://web.archive.org/web/20070328010015/http://www.cnn.com/SPECIALS/cold.war/experience/the.bomb/broken.arrows/content/1980c.html <!-- Bot retrieved archive --> |archive-date = 2007-03-28}}</ref>
|-
|October 1988
|Rocky Flats Plant, Golden, Colorado, US
|Contamination, exposure of workers
|At the nuclear pit fabrication facility at [[Rocky Flats Plant|Rocky Flats]] in [[Colorado]], two employees and a [[United States Department of Energy]] inspector inhaled radioactive particles, causing closure of the plant. Several safety violations were cited, including uncalibrated monitors, inadequate fire equipment, and groundwater contaminated with radioactivity.
|}

==1990s==

{| class="wikitable toptextcells"

|-
! Date
! Location
! Type
! Description
|-
| 1997 
| [[Georgia (country)|Georgia]] 
| Radiological accident
| Soldiers suffered radiation poisoning and burns. They were eventually traced back to training sources abandoned, forgotten, and unlabeled after the [[dissolution of the Soviet Union]]. One was a [[Caesium-137|<sup>137</sup>Cs]] pellet in a pocket of a shared jacket which put out about 130,000 times the level of background radiation at a {{convert|1|m|ft|adj=on|spell=in}} distance.<ref>{{cite journal | last=Lluma | first=Diego | title = Former Soviet Union: What the Russians left behind | journal = Bulletin of the Atomic Scientists |date=May–June 2000 | volume = 56 | issue = 3| pages = 14–17 | doi=10.2968/056003005 | s2cid=145248534 }}</ref>

|}

==2000s==

{| class="wikitable toptextcells"

|-
! Date
! Location
! Type
! Description

|-
| February 2003
| [[Y-12 National Security Complex|Y-12 facility]], [[Oak Ridge, Tennessee]]
| Processing vessel explosion
| [[File:Y-12 Aerial.jpg|thumb|Y-12 National Security Complex]]
During the final testing of a new saltless [[uranium]] processing method, there was a small explosion followed by a fire. The explosion occurred in an unvented vessel containing unreacted calcium, water and [[depleted uranium]]. An [[exothermic]] reaction in the vessel generated enough steam to burst the container. This small explosion breached its [[glovebox]], allowing air to enter and ignite some loose uranium powder. Three employees were contaminated. BWXT Y-12 (now B&W Y-12), a partnership of [[BWXT|Babcock & Wilcox]] and [[Bechtel]], was fined $82,500 for the accident.<ref>{{cite news | author = Parson P | title = BWXT Y-12 fined for explosion, fire | url = http://nucnews.net/nucnews/2004nn/0406nn/040612nn.htm#010 | publisher = The Oak Ridger | date = 2004-06-11 | access-date = 2007-06-17 | archive-date = 2016-03-12 | archive-url = https://web.archive.org/web/20160312121937/http://nucnews.net/nucnews/2004nn/0406nn/040612nn.htm#010 | url-status = dead }}</ref>

|}

==2010s==

{| class="wikitable toptextcells"

|-
! Date
! Location
! Type
! Description

|-
| 8 August 2019
| [[State Central Navy Testing Range]] near [[Nyonoksa]]
| Explosive destruction of a nuclear power source
| {{main|Nyonoksa radiation accident}}

According to the version presented by Russian officials, it was a result of a failed test of an "[[Atomic battery|isotope power source]] for a liquid-fuelled rocket engine".<ref>{{Cite news|url=https://www.theguardian.com/world/2019/aug/10/russian-nuclear-agency-confirms-role-in-rocket-test-explosion|title=Russian nuclear agency confirms role in rocket test explosion|last=Roth|first=Andrew|date=10 August 2019|work=The Guardian|access-date=2019-08-10}}</ref><ref>{{cite web|last=Johnson|first=Reuben |url=https://thebulwark.com/how-russia-is-tempting-fate-and-the-next-chernobyl/|title=How Russia Is Tempting Fate—And the Next Chernobyl|website=The Bulwark|date=15 August 2019|access-date=2019-08-16}}</ref><ref>{{Cite news|url=https://www.nytimes.com/2019/08/10/world/europe/russia-explosion-radiation.html|title=Russia Confirms Radioactive Materials Were Involved in Deadly Blast|last=Kramer|first=Andrew E.|date=10 August 2019|work=The New York Times|access-date=2019-08-10}}</ref> Nonproliferation expert [[Jeffrey Lewis (academic)|Jeffrey Lewis]] and [[Federation of American Scientists]] fellow Ankit Panda suspect the incident resulted from a test of the [[9M730 Burevestnik|Burevestnik]] cruise missile.<ref name=reuterblast>{{Cite news|url=https://www.reuters.com/article/us-russia-blast-usa-idUSKCN1UZ2H5|title=U.S.-based experts suspect Russia blast involved nuclear-powered missile|last=Landay|first=Jonathan |date=10 August 2019|work=Reuters|archive-url=https://web.archive.org/web/20190811085231/https://www.reuters.com/article/us-russia-blast-usa-idUSKCN1UZ2H5|archive-date=2019-08-11 |url-status=live |access-date=2019-08-12}}</ref> However, other arms control experts disputed the assertions; Ian Williams of the [[Center for Strategic and International Studies]] and [[James M. Acton|James Acton]] of the [[Carnegie Endowment for International Peace]] expressed skepticism over Moscow's financial and technical capabilities to field the weapon,<ref>{{cite news|title=Is Russia's Doomsday Missile Fake News?|url=https://foreignpolicy.com/2019/08/22/is-russias-doomsday-missile-fake-news-putin-hypersonic-nuclear-cruise-moscow-kremlin/|publisher=[[Foreign Policy]]|date=22 August 2019}}</ref> while [[Michael Kofman]] of the [[Woodrow Wilson International Center for Scholars|Wilson Center]] concluded that the explosion was probably not related to [[9M730 Burevestnik|Burevestnik]] but instead to the testing of another military platform.<ref>{{cite news|url=https://russianmilitaryanalysis.wordpress.com/2019/08/15/mystery-explosion-at-nenoksa-test-site-its-probably-not-burevestnik/| author=Michael Kofman|title=Mystery explosion at Nenoksa test site: it's probably not Burevestnik|date=15 August 2019}}</ref> According to [[CNBC]], the Russians were trying to recover a missile from the seabed which was lost during a previously failed test.<ref name=CNBC29082019>{{cite news |url=https://www.cnbc.com/2019/08/29/intel-says-russian-explosion-was-not-from-nuclear-powered-missile-test.html |title=US intel report says mysterious Russian explosion was triggered by recovery mission of nuclear-powered missile, not a test |work=CNBC |last=Macias |first=Amanda |date=21 August 2019 |access-date=11 October 2019}}</ref>

|}

==See also==
{{Portal|Nuclear technology}}
*[[1983 Soviet nuclear false alarm incident]]
*[[International Nuclear Event Scale]]
*[[List of accidents and incidents involving military aircraft]]
*[[Lists of disasters]]
*[[Nuclear weapon]]
*[[Radiation]]
*[[United States military nuclear incident terminology]]
*[[Vulnerability of nuclear plants to attack]]
*[[Broken Arrow (nuclear)]]

== Notes and references ==
{{reflist|group=nb}}
{{Reflist|35em}}

== Bibliography ==
* [http://alsos.wlu.edu/qsearch.aspx?browse=issues/Nuclear+Accidents+-+Military Annotated bibliography from the Alsos Digital Library for Nuclear related Issues and Incidents]
* {{in lang|fr}} Jean-Hugues Oppel, ''Réveillez le président !'', Éditions Payot et rivages, 2007 ({{ISBN|978-2-7436-1630-4}}). The book is a fiction about the [[Force de Frappe|nuclear weapons of France]]; the book also contains about ten chapters on true historical incidents involving nuclear weapons and strategy  (during the second half of the twentieth century).
* Nilsen, Thomas, Igor Kudrik and Alexandr Nikitin. [http://spb.org.ru/bellona/ehome/russia/nfl/The Russian Northern Fleet: Sources of Radioactive Contamination]{{dead link|date=January 2017}}. ''Bellona Report'' 2:1996, 28. August 1996.
* {{cite book|title=Command and Control: Nuclear Weapons, the Damascus Accident, and the Illusion of Safety|url=https://archive.org/details/commandcontrol00eric|url-access=registration|author=Eric Schlosser|year=2013|publisher=Penguin Press|isbn=978-1594202278}}
*''The Limits of Safety'' (1993, Princeton University Press) by Scott Sagan {{ISBN?}}

==External links==
*[https://web.archive.org/web/20080518071708/http://www.progettohumus.it/nucleare.php?name=specialtrinity ProgettoHumus: From Trinity Test to...] List of nuclear explosions in the world
*[http://www.progettohumus.it/public/forum/index.php?topic=40.0 ProgettoHumus] {{Webarchive|url=https://web.archive.org/web/20110722050554/http://www.progettohumus.it/public/forum/index.php?topic=40.0 |date=2011-07-22 }} List of all nuclear accidents in the history (updated)
*[http://alsos.wlu.edu/adv_rst.aspx?keyword=accidents*military&creator=&title=&media=all&genre=all&disc=all&level=all&sortby=relevance&results=10&period=15 Bibliography of military nuclear accidents from the Alsos Digital Library for Nuclear Issues] {{Webarchive|url=https://web.archive.org/web/20110606113108/http://alsos.wlu.edu/adv_rst.aspx?keyword=accidents*military&creator=&title=&media=all&genre=all&disc=all&level=all&sortby=relevance&results=10&period=15 |date=2011-06-06 }}
*[https://web.archive.org/web/20031221154956/http://www.thememoryhole.org/nukes/mod-nuke-accidents.htm Official List of accidents involving nuclear weapons from the UK Ministry of Defence]
*[http://schema-root.org/technology/nuclear/power/accidents/ Schema-root.org: Nuclear Power Accidents ] 2 topics, both with a current news feed
*[https://www.nrc.gov/ US Nuclear Regulatory Commission (NRC) website] with search function and electronic public reading room
*[http://www.iaea.org/ International Atomic Energy Agency website] with extensive online library
*[http://www.nuclearactive.org/ Concerned Citizens for Nuclear Safety] Detailed articles on nuclear watchdog activities in the US
*[https://web.archive.org/web/20060222055940/http://www.world-nuclear.org/education/ne/neap1.htm Radiation Doses] Background on ionizing radiation and doses, [[World Nuclear Association]]
*[http://www.ccohs.ca/oshanswers/phys_agents/ionizing.html Canadian Centre for Occupational Health & Safety] More information on radiation units and doses.
*[http://www.johnstonsarchive.net/nuclear/radevents/index.html Radiological Incidents Database] Extensive, well-referenced list of radiological incidents.
*[https://web.archive.org/web/20071012030433/http://www.nuclearfiles.org/menu/key-issues/nuclear-weapons/issues/accidents/20-mishaps-maybe-caused-nuclear-war.htm 20 Mishaps That Might Have Started Accidental Nuclear War] A handy (if somewhat chilling) list of close calls.
*[https://web.archive.org/web/20001118115400/http://www.cdi.org/Issues/NukeAccidents/accidents.htm US Nuclear Weapons Accidents] list published by the Center for Defense Information ([http://www.cdi.org/ CDI])
*[https://www.gutenberg.org/ebooks/277 Trinity Atomic Bomb by U.S. National Atomic Museum]

{{Nuclear and radiation accidents and incidents}}
{{Disasters}}

{{DEFAULTSORT:Military Nuclear Accidents}}
[[Category:Military nuclear accidents and incidents| ]]
[[Category:Nuclear safety and security|*]]
[[Category:Lists of nuclear disasters]]
[[Category:Non-combat military accidents|Nuclear]]
[[Category:Nuclear technology-related lists]]