MILNET Mirror Document

Center For Defense Information

The DEFENSE MONITOR

Attached are unclassified summaries describing the circumstances surrounding 32 accidents involving nuclaer weapons. Also attached is the Department of Defense (DOD)/Department of Energy (DOE) definition of "accident" used in researching this project.

Twenty-six of these summaries were first released by the Air Force in 1977; another was prepared following the Titan II explosion in Arkansas in September 1980.

There never has been even a partial inadvertant U.S. nuclear detonation despite the very severe stresses impossed upon the weapons involved in these accidents. All "detonations" reported in the summaries involved conventional high explosives (HE) only. Only two accidents, those at Palomares and Thule, resulted in widespread dispersal of nuclear materials.

Nuclear weapons are never carried on training flights. Most of the aircraft accidents represented here occurred during logistic/ferry missions or airborne alert flights by Strategic Air Command (SAC) aircraft. Airborne alert was terminated in 1968 becaus of:

• Accidents, particulary those at Palomares and Thule,
• The rising cost of maintaining a portion of the SAC bomber force constantly on airborne alert, and,
• The advent of a responsive and survivable intercontinental ballistic missile force which relieved the manned bomber force of a part of its more time-sensitive responsibilities. (A portion of the SAC force remains on a nuclear ground alert.) [Since 1/97, U.S. nuclear ground force is no longer on alert, silo launched weapons have been or in the process of being dismantled, and nuclear submarine forces are no longer able to independently fire their missiles. - MILNET]

Since the location of a nuclear weapon is classified defense information, it is Department of Defense policy normally neither to confirm or deny the presence of nuclear weapons at any specific place. In the case of an accident involving nuclear weapons, their presence may or may not be divulged at the time depending upon the possibility of public hazard or alarm. Therefore, in some of the events summarized here, the fact of the presence of nuclear weapons or materials may not have been confirmed at the time. Furthermore, due to diplomatic considerations, it is not possible to specify the location of the accidents that occurred overseas, except for Palomares and Thule.

Most of the weapon systems involved in these accidents are no longer in the active inventory. Those include the B-29, B-36, B-47, B-50, B-58, C-124, F-100, and P-5M aircraft, and the Minuteman I missile [BOMARC]. With some early models of nuclear weapons, it was standard procedure during most operations to keep a capsule of nuclear material separate from the weapon for safety purposes. While a weapon with the capsule removed did contain a quantity of natural (not enriched) uranium with an extremely low level of radioactivity, accidental detonation of the HE element would not cause a nuclear detonation or contamination. More modern designs incorporate improved redundant safety features to insure that a nuclear explosion does not occur as a result of an accident.

This list of accidents was complied by DOD/DOE researchers during December 1980-January 1981. The researchers reviewed all available records of the military services and DOE, applying current definitions to determine if an event warranted categorization as an accident.

For example, one event not covered by these narratives was included in a "Chronology of Nuclear Accident Statements," released by DOD in 1968:

"March 18, 1963, Titan (I) Missile Burned in Silo near Moses Lake, Washington."

The researchers found, however, that only a small retrorocket on the missile had accidentally fired. The missile and its warhead were not damaged. That event does not warrant inclusion in a list of accidents involving nuclear weapons.

Another event from the 1968 list, involving a U.S. Navy Terrier missile (January 20, 1966; NAS Mayport, Florida) was not considered to be an accident, it has been categorized as a significant incident. In that incident, a nuclear warhead separated from the missile, and fell about eight feet [aboard the USS Luce, a guided missile frigate. The event occurred on January 19]. The warhead was dented; no other damage occurred.

The events outlined in the attached narratives involved operational weapons, nuclear materials, aircraft and/or missiles under control of the U.S. Air Force, U.S. Navy or

No. 1 , February 13, 1950/B-36/Pacific Ocean, off Coast of British Columbia
The B-36 was enroute from Eielson Air Force Base, [near Fairbanks, Alaska] to Carswell Air Force Base [Fort Worth, Texas] on a simulated combat profile mission. The weapon aboard the aircraft had a dummy capsule installed. After six hours of flight, the aircraft developed serious mechanical difficulties, making it necessary to shut down three engines. The aircraft was at 12,000 feet altitude. Icing conditions complicated the emergency and level flight could not be maintained. The aircraft headed out over the Pacific Ocean and dropped the weapon from 8,000 feet. A bright flash occurred on impact, followed by a sound and shock wave. Only the weapon's high explosive material detonated. The aircraft was then flown over Princess Royal Island where the crew bailed out. The aircraft wreckage was later found on Vancouver Island.

CDI: Sixteen crewman and one passenger parachuted safely and were rescued. An accompanying B-36 flew safely to Carswell Air Force Base. No mention is made of an attempt to recover the nuclear weapon and presumably it is still in the ocean. As early as 1950 nuclear weapons were carried to and from Alaska. The B-36 was operational from 1948-1959 and 325 were built.

CDI: The New York Times reported the B-29 crashed in a "remote secret area of Sandia Special Weapons Base...and burned, shooting up flames visible for fifteen miles." Manzano Mountain was used as a "dead storage" site where outmoded weapons were stored. The B-29 was the United States' first nuclear delivery aircraft and comprised the majority of our strategic bomber force through 1952. The Enola Gay was a B-29 which dropped the bomb on Hiroshima. By June 1948 only 32 B-29s were modified to deliver nuclear weapons. All were assigned to 509th Bomb Group. The B-29 was operational from 1943-1954; 3970 were built.

CDI: The explosion was heard over a radius of 25 miles and made a crater 25 feet deep and 200 feet square. The B-50 was an improved derivative of the B-29 with the same general appearance. It was operational from 1948-1953 and 370 were built.

CDI: The aircraft crashed near a trailer camp occupied by 200 service families. The exposion of 10-12 500 lb. conventional explosive bombs shattered more than half of the fifty automobiles and trailers, blasted a crater 20 yards across and six feet deep and was felt 30 miles away. The fire could be seen for 65 miles. There were also 60 people hurt.

CDI: There is no record of recovery of this nuclear weapon.

CDI: This dissappearance of the B-47, its crew, and nuclear weapons material was assumed to be an accident. The B-47 was America's first jet bomber and was operational from 1951-1956. Faster than its predecessors, it lacked the range to reach the Soviet Union from the U.S. and thus bases were established in England and French Morocco in 1950-51. 2060 B-47s were built.

CDI: The crash occurred at Lakenheath Royal Air Force Station, 20 miles northeast of Cambridge, England. The plane was part of hte 307th Bombardment Wing and had recently come from Lincoln Air Force Base, Nebraska. As part of what was called "Operation Reflex," B-47 bombers were regularly rotated, usually on a 90-day basis, to bases in the United Kingdom and North Africa. In the storage igloo were three Mark 6 nuclear bombs, each 12 feet long and 6 feet in diamter. Each bomb had about 8000 lbs. of TNT as part of its trigger mechanism. The blazing jet fuel did not ignite TNT and was extinguished by the base fire fighters. The four crewman were killed. "It is possible that a part of Eastern England would have become a desert" had the TNT exploded and showered radioactive materials over a wide area, said a now retired Air Force general who was in the U.K. at the time. "It was a combination of tremendous heroism, good fortune and the will of God," said a former Air Force officer who was on the scene.

It is not clear when American nuclear weapons were first deployed to Europe. The process went through several stages. In early July 1950 President Truman approved forward bases in England. On December 6, 1950 President Truman endorsed the Joint Chiefs' request that non-nuclear components of atomic bombs be stocked on board the aircraft carrier, USS Franklin Roosevelt, stationed in the Mediterrannean.

CDI: In a New York Times report of the 1968 list of accidents, there is mention of a B-36 bomber dropping an atomic bomb near Kirtland Air Force Base in 1956 that was publicly reported. Either a similar event did occur in 1956 or it has been confused with this event.

Inadvertent Explosion "Nuclear weapons are designed with great care to explode only when deliberately armed and fired. Nevertheless, there is always a possibility that, as a result of accidental circumstances, an explosion will take place inadvertently. Although all conceivable precautions are taken to prevent them, such accidents might occur in areas where weapons are assembled and stored, during the course of loading and transportation on the ground, or when actually in the delivery vehicle, e.g., an airplane or a missile." Atomic Energy Commission/Department of Defense The Effects of Nuclear Weapons 1962

CDI: Three of the 32 accidents occurred while transporting nuclear weapons from one place to another, using the C-124 "Globemaster" transport. In this instance weapons and a nuclear capsule were being taken to Europe. The weapons were jettisoned within an area 100 miles southeast of the Naval Air Station, Pomona, N.J. where the aircraft landed. The two weapons are still presumably in the area, somewhere east of Rehobeth Beach, Delaware, Cape May and Wildwood, N.J. Plutonium-239, an isotope used to fuel atomic bombs has a half-life of 24,400 years and remains poisonous for at least half a million years. [why CDI chose to mention this does not make sense...the nuclear material capsule contains the critical mass of enriched fuel - MILNET]

CDI: Four crewmen were killed.

CDI: The crash might have taken place at a U.S. air base in Sidi Slimane, French Morocco. An earlier Air Force document reported, "Contamination of the wreckage was high, but that of the surrounding area was low." The New York Times of June 8, 1960 mentions a nuclear weapons accident having occurred" at a United States field near Tripoli, Libya," but gives no date.

CDI: Some accounts of nuclear weapons accidents list a February 12, 1958 accident involving a B-47 off Savannah, Georgia. An earlier DOD narrative was more precise on where it landed. "The best estimate," they say, "was determined to be 31 degress xx' yy" North, 80 degrees xx' yy" West." [coordinates censored by MILNET - MILNET]

CDI: Accounts of this widely reported accident describe the bomb falling in garden of the home of Mr. Walter Gregg in Mars Bluff, S.C. The high explosive detonation virtually destroyed his house creating a crater 50-70 feet in diameter adn 25-30 feet deep. It caused minor injuries to Mr. Gregg and five members of his family, and additionally damaged five other houses and a church. The clean-up effort required several days. Air Force personnel recovered hundreds of pieces of bomb fragments that were carried off as souvenirs by local residents. The inhabitants of Mars Bluff were examined for several months to see if they had been exposed to any radiation. Five months later the Greeg family was awarded $54,000 from the Air Forc. After this accident Air Force crews were ordered t "lock in" nuclear bombs. This reduced the possibility of accidental drops but increased the hazards if the plane crashed.

Triggering a Nuclear Exchange "The explosion of a nuclear device by accident--mechanical or human--could be a disaster for the United States, for its allies, and for its enemies. If one of these devices accidentally exploded, I would hope that both sides had sufficient means of verification and control to prevent the accident from triggering a nuclear exchange. But we cannot be certain that this would be the case." John T. McNuaghton Assistant Secretary of Defense 1962 [Fiction writers in the military genre postulate that U.S. NUDET satellites are able to pinpoint the type of nuclear weapon causing a nuclear detonation by the spectra observed. As an example read Tom Clancey's Sum of All Fears - MILNET]

CDI: This is the eighth and last acknowledged B-47 accident, making it the most accident-prone of the nuclear-capable systems reported.

CDI: During the late 1950s and early 1960s, the F-100 Super Sabre served as a primary interceptor. The F-100 could carry nuclear capable air-to-air missiles. In 1959 the United States had bases in the Pacific on Okinawa, in the Philippines, Taiwan, South Korea, and Thailand. 2,294 F-100s of all types were produced [bomb racks for arming fighters with special weapons-- read nuclear weapons--were not compatible with conventional weapons and vice versus, thus disallowing the accidental mounting of a nuclear weapon in the place of a conventional weapon. Also, nuclear weapons of a size to be mounted on fighters in this period were most likely "boosted" tactical yield (less than 100kt) weapons...anything larger could not be lifted by even an afterburner equipped F-100 - MILNET]

CDI: The crew of ten was rescued. The prime mission of the P-5M was anti-submarine warfare. Weapons used for this purpose include nuclear depth charges which have an explosive power of 5-10 kilotons (one kiloton equals 1,000 tons of TNT). The bomb dropped on Hiroshima has been estimated to have been 13.5 kilotons [either would be considered a tactical nuclear weapon - MILNET].

CDI: The B-52 entered service in June 1955 and continues to be the primary aircraft for the strategic bomber force [due for retirement at the end of this year, 1997 - MILNET]. In 1959, the United States reached its peak bomber strength of 1,366 B-47s and 488 B-52s [one would assume this meant over 1,800 nuclear bombers - MILNET]. In the early 1960s, as much as 15% of the B-52 force (50-70) planes) was placed on airborne alert, in the air at all times armed and ready for attack. At that time B-52s carried from 1-4 nuclear bombs with yields between 1 and 24 megatons (one megaton equals 1,000,000 tons of TNT). The present strategic bomber force includes 316 B-52s and 60 FB-111s [circa 1981--in the year 1997, the fleet has a fraction of the B-52s, and also includes B-1B and B-2A bombers, and F-111s are no longer in the nuclear fleet. Also, few nuclear bombs are ever loaded (if at all) on aircraft, since the U.S. no longer have aircraft on nuclear alert - MILNET].

CDI: The BOMARC missile was one of the 56 housed at the 46th Air Defense Missile Squadron in Jackson Township, N.J., ten miles east of McGuire Air Force Base. Each missile was housed in a separate concrete and steel shelter. The BOMARC had earned a reputation as a dangerous weapon system. The New York Times reported the 47-foot missile "melted under an intense blaze fed by its 100-pound detonator TNT...THe atomic warhead apparently dropped into the molten mass that was left of the missile, which burned for forty-five minutes." The radiation "had been caused when thoriated magnesium metal which forms part of the weapon, caught fire,... the metal, already radioactive, becomes highly radioactive when it is burned." [interesting but faulty analysis - MILNET]

CDI: The crew of eight survived though a fireman died extinguishing the fire. The nuclear weapons involved could have been either the free fall bombs located in the interior bomb bay compartment or "Hound Dog" (AGM-28B) air-to -ground missiles which are carried in pairs underneath the wings of B-52s. The Hound Dog was a stand-off nuclear tipped strategic missile with a range of 500-600 miles. It was intertially guided and powered by a turbo-jet, air- breathing engine and had a warhead of about 1 megaton. It was first assigned to SAC in late 1959, and was part of the Air Force's nuclear inventory until it was phased out in 1977.

By July 1961, SAC had increased the percentage of the bomber force on 15-minute ground alert from approximately 33% to 50%. [Note that the pilot risked his life to guide the buff away from Marysville- Yuba City area. We can only hope he received the DFC - MILNET]

components of nuclear weapons caused minor injuries to three Atomic Energy Commission employees. There was little contamination from the nuclear components stored elsewhere in the building. The components were from obsolete weapons being disasembled.

CDI: While three employees were dismantling the high-explosive component of a nuclear bomb it began burning spontaneously, setting off the larger amount of high explosives. Three other accounts of accidents (as well as this one) involving components of nuclear weapons were suplied to Dr. Joel Larus of New York University by the AEC on January 13, 1966:

Hamburg, New York (January 4, 1958)...An eastbound Nickel Plate railroad freight train was derailed, and five cars carrying "AEC classified material" were involved in the accident. According to the report there was no damage to the material and no injury to AEC personnel escorting the shipment.

Winslow, Arizona (November 4, 1961)...A trailer truck caught fire wile carrying a small amount of radioactive material. There was no contamination resulting from the fire.

Marietta, Georgia (December 2, 1962)...A Louisville and Nashville train was derailed while carrying nuclear weapons components. The material was not damaged, but three couriers were injured.

Accidents of this sort probably happen more frequently than reported. In December 1980 a Department of Energy trailer carrying plutonium overturned on icy roads on Interstate 25 near Fort Collins, Colorado, on its way from Richland, Washington, to Los Alamos, New Mexico [see Nuclear Weapons Couriers on MILNET - MILNET]. Each year hundreds of nuclear convoys [approximately 50 tractor-trailer combos according to DoT - MILNET] travel millions of miles [total miles for all years up to 1996 was stated as 3.5 million miles by DoT - MILNET] on U.S. highways. Even when there is no accident, exposure over a period of years to radioactive material by certain Department of Energy couriers and privately contracted transporters and personnel may be carcinogenic. It has been estimated that nearly 120,000 persons have access to U.S. nuclear weapons and weapons-grade fissionable material. A study on the hazards of low level, intrinsic radiation inherent in nuclear weapons is being conducted by the Defense Nuclear Agency and will be released in 1982.

The weapons work at Mediana was phased out in 1966 and consolidated with production activities in the Pantex, Texas (near Armarillo) and Burlington, Iowa, final assembly plants.

CDI: The Minuteman I was a three stage intercontiental ballistic missile [ICBM - MILNET] carrying a one megaton warhead. The first missiles became operational in November 1962. Throughout the 1960s and 1970s they were gradually replaced by Minuteman IIs and IIIs. The Office of Technology Assessment study calculated that a one megaton surface burst in Detroit would cause 70 square miles of property destruction, a quarter of a million fatalities, and half a million injuries.

CDI: The B-58 [Hustler - MILNET] supersonic bomber was operational from 1960-69 and 104 were built [until the B-1B went into service, the B-58 was had been the highest performance bomber capable of carrying the five huge nuclear weapons in its bomb bay. also, the B-58 was configurable to carry a large fuel tank on its belly at the centerline, which had to be ejected in order to open the bomb bay doors. - MILNET]

CDI: The A-4 is [no longer in U.S. service - MILNET] a lightweight attack bomber. The weapon may have been a B-43 nuclear bomb.

CDI: The DOD summary is ia typically low-key account of the most well publicized nuclear accident which resulted in what has been described as "the most expensive, intensive, harrowing and feverish underwater search for a man-made object in world history." The B-52 was returning to Seymour Johnson Air Force Base at Goldsboro, North Carolina, after flying the southern route of the SAC air alert missions (code named "Chrome Dome"). It was attempting its third refueling of the mission with a KC-135 tanker from the American base at Moron, southwestern Spain, near Sevilla. Although the official report of the cause of the accident was not released to the public, it is believed that while attempting to dock at 30,000 ft above the Spanish coast, the nozzle of the tanker's boom, which was supposed to hook up with the B-52's orifice, struck the bomber, ripping open the B-52 along its spine and causing aerodynamic stress which snapped the bomber into pieces. Flames spurted through both planes and the KC-135s 40,000 gallons of jet fuel ignited, killing its four crew members almost immediately. Four of the seven crew members of the B-52 managed to eject and parachute to safety.

As the two planes, worth $11,000,000 and weighing loaded nearly 800,000 lbs., crashed and burned, wreckage fell across an area of land and water of about 100 square miles. Of the four H-bombs (believed to be in the 20-25 megaton range) aboard, one fell to earth and remained relatively intact, two [were destroyed, - MILNET] scattered plutonium widely over the fields of Palomares when their high explosive material detonated, and one [the fourth - MILNET] fell into the ocean. For the next three months the village was turned upside down as the search, decontamination and removal operation began. Estimates for the amount of radioactive soil and vegetation removed to the nuclear dumping site at Aiken, South Carolina, range up to 1,750 tons.

Accidental Nuclear War "Despite the most elaborate precautions, it is conceivable that technical malfunction or human failure, a misinterpreted incident or unauthorized action, could trigger a nuclear disaster or nuclear war." Introduction of U.S.-Soviet Treaty U.S. Arms Control and Disarmament Agency September 1971

The weapon that sank in the Mediterranean caused the greatest problem. Its recovery required the assembly of a naval task force, including a small armada of miniature research submarines, scuba teams, sonar experts, nuclear weapons engineers, oceanic photographers, and hundreds of sailors aboard ships of the Sixth Fleet which were called in to seal the area. It took two weeks for the midget sub "Alvin" to sight the bomb, entangled in its parachute 12 miles off Palomares on a 70 degree slope at a depth of 2,500 feet. After a series of failed attempts, the bobm was finally recovered on April 7, dented but intact, with no known radiation leakage. The Palomares search took about eighty days and required services of 3,000 Navy personnel and 33 Navy vessels, not counting ships, planes, and people used to move equipment to the site. By 1969, a U.S.Commission had settled 522 claims by Palomares residents totalling $600,000. It also gave the town of Palomares the gift of a desalting plant, which cost about $200,000 to build.

CDI: The B-52 was flying the Artic Circle route as part of the continuous airborne alert operation, "Chrome Dome," involving anywhere from 6 to 50 B-52s. A fire broke out in the navigator's compartment and was soon out of control, spreading smoke throughout the plnae. The pilot headed the bomber towards Thule Air Base, located about 700 miles above the Arctic Circle on the northwestern Greenland coast, to attempt an emergency landing. The seven crew members had to eject when the plane was at about 8-9,000 feet and about four miles south of the runway. Six of the crew members parachuted to safety with only slight injuries while one, the co-pilot died. After it was abandoned, the plane did a 180 degree turn and crashed onto the ice of North Star Bay, seven and one-half miles southwest of Thule, whereupon it skidded across the ice in flames and exploded. It is believed that the high explosives in the outer coverings of the four 1.1 megaton H-Bombs aboard detonated, releasing radiation from the plutonium in the bombs and causing fires which destroyed all four. Wreckage of the plane was widely scattered in an area about 300 yards on either side of the plane's path, much of it in "cigarette box-sized" pieces.

A team of 70 Air Force and civilian specialists were flown in to monitor radiation and search for debris and the bombs, soon followed by the Navy's special team which at worked at Palomares. The bombs' parts were discovered and ten days later on the snow within 1,000 feet of the path of the plane.

A massive collection and removal effort began. The contaminated ice and crash debris were removed to the United States, the bomb debris to the AEX Pantex plant at Amarillo, Texas, where the bombs had been manufactured. A few days after the crash, Secretary of Defense McNamara ordered the removal of nuclear weapons on airborne alert. The alerts were later curtailed and then suspended altogether.

The government of Denmark, which owns Greenland and prohibits nuclear weapons on or over their territory, issued a strong protest. There were large demonstrations throughout Denmark against the U.S. and its base at Thule. Costs of the crash, clean-up and compensation ran into the millions of dollars.

CDI:The accident probably refers to the nuclear powered attack submarine USS Scorpion. The Scorpion was last heard from on May 21, 1968. It was returning to Norfolk, Va. after a three month training exercise with the Sixth Fleet in the Mediterranean. It sank 400-500 miles southwest of the Azores. Initial suspicion that the Soviets were somehow involved was allayed when the research ship Mizar photographed the wreckage lying at 10,000 feet on the sea floor. A Navy seven-man court of inquiry met for eleven weeks and heard 90 witnesses. The found "No evidence of any kind to suggest foul play or sabotage," and that the "certain cause of the loss of the scorpion cannot be ascertained from evidence now available." Ninety-nine men were lost. The nuclear weapons aboard may have been either SUBROC [Submarine launched ROCkets propelled depth charge - MILNET] or ASTOR, or both. SUBROC, first deployed in 1965, is an anti-submnarine missile and nuclear depth charge. Attack submarines normally carry 4-6 SUBROCs, which have a range of 25-30 miles and high explosive power. ASTOR is the nuclear version of the MK45 torpedo which went into service around 1960 and has low explosive power.

CDI: The explosion of volatile fuel blew off the 740 ton silo door of reinforced concrete and steel and catapulted the warhead 600 feet. The 54 liquid-fueled Titan II missiles have been operational since 1963 [no liquid fuel silo missiles remain in operation today - MILNET]. It is estimated that Titan II ICBMs carry a 9 megaton warhead. The Office of Technology Assessment study estimated that a 9 megaton airburst on Leningrad would result in 2.4 million fatalities and 1.1 million injuries. With age, the seals on the missiles are corroding, increasing the number of leaks. The worst missile accident occured in Searcy, Arkansas on August 9, 1965, when a fire in a Titan II silo killed 53. The Air Force has disclosed that between 1975 and 1979 there have been 125 accidents at Titan sites in Arkansas, Arizona and Kansas. From March 1979 to September 1980 there were ten other leaks and accidents at Arkansas Titan sites. On August 24, 1978 at a Titan sit in Rock, Kansas, two airmen were killed and thirty others injured when they were exposed to deadly oxidizer gas. The silo at Damascus, Arkansas will be filled in with gravel while that at Rock, Kansas is being refurbished and is planned to be operational in September 1982.

• The Department of Defense report on nuclear weapons accidents is a clear warning of the continuing danger of nuclear accidents.
• The variety of nuclear weapons accidents which have occurred in the past and the increased numbers of nuclear weapon suggest that more accidents and perhaps more serious accidents will occur in the future.
• A General Accounting Office or other governmental organization investigation is needed to identify major risks and preventive measures in order to reduce the possibility of accidents in the future.
• Development and promulgation of U.S. government plans for handling emergencies arising from nuclear weapons accidents could reduce civilian casualties in areas where nuclear weapons are handled.

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