Largest artificial non-nuclear explosions

There have been a number of extremely large explosions, many accidental, caused by modern high explosives, BLEVEs, older explosives such as gunpowder, volatile petroleum-based fuels such as gasoline (petrol), and other chemical reactions. This list contains the largest known examples, sorted by date. An unambiguous ranking in order of severity is not possible; a 1994 study by historian Jay White of 130 large explosions suggested that they need to be ranked by an overall effect of power, quantity, radius, loss of life and property destruction, but concluded that such rankings are difficult to assess. The weight of an explosive does not directly correlate with the energy or destructive impact of an explosion, as these can depend upon many other factors such as containment, proximity, purity, preheating, and external oxygenation (in the case of thermobaric weapons, gas leaks and BLEVEs).

Before 1900

Fall of Antwerp

On 4 April 1585, during the Spanish siege of Antwerp, a fortified bridge named "Puente Farnesio" had been built by the Spanish on Scheldt river, in order to isolate the city of any reinforcement. With the purpose of breaking the bridge, the Dutch designed four large fire ships, filled with a huge amount of gunpowder and rocks. Three of the fire ships failed the target, but one of 800 tons clashed with "Puente Farnesio". It did not explode immediately, which gave time to some curious Spaniards to board her. Then, a devastating blast killed 800 Spaniards on the bridge, throwing bodies, rocks and pieces of metal several kilometers away. A little tsunami took place in Scheldt river, the Earth shook for miles around and a big, dark cloud covered the area. The blast could be felt as far as 35 kms away, in the city of Ghent, where windows vibrated.

Great Torrington, Devon

On 16 February 1646, 80 barrels (57.2 tons) of gunpowder were accidentally ignited by a stray spark during the Battle of Torrington in the English Civil War, destroying the church in which the magazine was located and killing several Royalist guards and a large number of Parliamentarian prisoners who were being held there. The explosion effectively ended the battle, bringing victory to the Parliamentarians. It narrowly missed killing the Parliamentarian commander, Sir Thomas Fairfax. Great damage was caused in the town.

Delft Explosion

About 40 tonnes of gunpowder exploded on 12 October 1654, destroying much of the city of Delft in the Netherlands. Over a hundred people were killed and thousands were wounded.

Destruction of the Parthenon

On 26 September 1687, the famous and until-then-intact Greek monument was destroyed when an Ottoman ammunition bunker inside was struck by a mortar. 300 Turkish soldiers were killed in the explosion.

Bastion of San Nazaro, Brescia

In 1769, the Bastion of San Nazaro is Brescia, Italy was struck by lightning. The resulting fire ignited 90 tonnes of gunpowder being stored, and the subsequent explosion leveled one-sixth of the city and killed 3,000 people.

Siege of Almeida (1810)

On 26 August 1810, in Almeida, Portugal, during the Peninsular War phase of the Napoleonic Wars, French forces commanded by Marshall André Masséna laid siege to the garrison, commanded by British Brigadier General William Cox. A shell made a chance hit on the old castle, which was being used as the main powder magazine. It initially ignited some 4,000 prepared charges, which in turn ignited 68 000 kg of black powder and 1,000,000 musket cartridges. The ensuing explosion killed 600 defenders and wounded 300. The castle was razed to the ground and sections of the defenses were damaged. Unable to reply to the French cannonade without gunpowder, Cox was forced to capitulate the following day with the survivors of the blast and 100 cannon. The French lost 58 killed and 320 wounded during the operation.

Siege of Multan

On 30 December 1848, in Multan during the Second Anglo-Sikh War, "A shell from a mortar struck a mosque in the city which had been turned into a magazine and stored with 180 000 kg of gunpowder [200 short tons (180 t)]. It blew up with a tremendous explosion which shook the earth for many kilometers round, and darkened the air with smoke and fragments."

Palace of the Grand Master Explosion, in Rhodes

On 4 April 1856, the Ottomans had storaged a large amount of gunpowder in the palace and the adjacent church, which were also full of people. In that time, it was considered that the ringing of bells could prevent the formation of storms. Unfortunately, a lightning hit the gunpowder, triggering a huge blast that killed 4,000 people.

Mobile magazine explosion

On 25 May 1865, in Mobile, Alabama, in the Southern United States, an ordnance depot (magazine) exploded, killing 300 people. This event occurred just after the end of the American Civil War, during the occupation of the city by victorious Federal troops.

Flood Rock explosion

On 10 October 1885 in New York City, the U.S. Army Corps of Engineers detonated 140 000 kg of explosives on Flood Rock, annihilating the island, in order to clear the Hell Gate for the benefit of East River shipping traffic. The explosion sent a geyser of water 76 m in the air; the blast was felt as far away as Princeton, New Jersey. The explosion has incorrectly been described as "the largest planned explosion before testing began for the atomic bomb" — the detonation at the Battle of Messines was larger. Rubble from the detonation was used in 1890 to fill the gap between Great Mill Rock and Little Mill Rock, merging the two islands into a single island, Mill Rock.

Nanaimo mine explosion

An explosion on 3 May 1887 in Nanaimo, British Columbia, Canada, killed 150 miners.

Braamfontein explosion

On 19 February 1896, an explosives train at Braamfontein station in Johannesburg, loaded with between 56 and 60 tons of blasting gelatine destined for the burgeoning gold mines of the Witwatersrand and having been standing for three and a half days in searing heat, was struck by a shunting train. The load exploded, leaving a crater in the Braamfontein rail yard 60 meters long, 50 meters wide and 8 meters deep. The explosion was heard up to 200 kilometers away. At least 62 people were killed, and more than 200 were injured. Surrounding suburbs were destroyed, and roughly 3,000 people lost their homes. Almost every window in Johannesburg was shattered.

1901–2000

World War I era

DuPont Powder Mill explosion, Fontanet, Indiana

On October 15, 1907, approximately 40,000 kegs of powder exploded in the city of Fontanet, Indiana, killing between 50-80 people, and destroying the town. The sound of the explosion was heard over 320 km away, with damage occurring to buildings 40 km away.

Alum Chine

The Alum Chine was a Welsh freighter (out of Cardiff) carrying 343 tons of dynamite for use during construction of the Panama Canal. She was anchored off Hawkins Point, near the entrance to Baltimore Harbor in Baltimore, Maryland, USA. She exploded on 7 March 1913, killing over 30, injuring about 60, and destroying a tugboat and two barges. Most accounts describe two distinct explosions.

Faversham explosion

On 2 April 1916, a huge explosion ripped through the gunpowder mill at Uplees, near Faversham, Kent, when 200 tons of TNT ignited. 105 people died in the explosion. The munitions factory was next to the Thames estuary, which explains why the explosion was heard across the estuary as far away as Norwich, Great Yarmouth, and Southend-on-Sea, where domestic windows were blown out and two large plate-glass shop windows shattered.

Queen Mary explodes during the Battle of Jutland

Battle of Jutland

On 31 May 1916, three British battlecruisers were destroyed by magazine explosions initiated by shells of the German High Seas Fleet. At 16:02 HMS Indefatigable was cut in two by detonation of the forward magazine and sank immediately with all but 3 of her crew of 1,017. At 16:25 HMS Queen Mary was cut in two by detonation of the forward magazine and sank with all but 21 of her crew of 1,283. At 18:30 HMS Invincible was cut in two by detonation of the midships magazine and sank in 90 seconds with all but 6 of her crew of 1,032.

Lochnagar Mine

On the morning of 1 July 1916, a charge of 60,000 lb (27 t) of ammonal explosive was blown to start the Battle of the Somme. The explosions constituted what was then the loudest human-made sound in history, and could be heard in London. The mine created a crater 300 ft (90 m) across and 90 ft (30 m) deep, with a lip 15 ft (5 m) high. The crater is known as Lochnagar Crater after the trench from where the main tunnel was started.

Black Tom explosion

On 30 July 1916, 1,000 short tons (910 t) of explosives bound for Europe, along with another 50 short tons (45 t) on the Johnson Barge No. 17, exploded in Jersey City, New Jersey, a major dock serving New York. There were few deaths, but about 100 injuries; also, the buildings on Ellis Island and the Statue of Liberty were damaged, along with much of Jersey City.

Silvertown explosion

On 19 January 1917, parts of Silvertown in East London were devastated by a massive TNT explosion at the Brunner-Mond munitions factory. 73 people died and hundreds were injured. The blast was felt across London and Essex and was heard over 100 mi (160 km) away, with the resulting fires visible for 30 mi (48 km).

Quickborn Explosion

On 10 February 1917 a chain reaction in an ammunition plant "Explosivstoffwerk Thorn" in Quickborn-Heide (northern Germany) killed at least 115 people (some sources say over 200), mostly young female workers.

Plzeň explosion

Škoda Works in Plzeň was the biggest ammunition plant in Austria-Hungary. A series of explosions on 25 May 1917 killed 202 workers and wounded 689. This event inspired Karel Čapek to write a novel Krakatit (1922).

Battle of Messines

On 7 June 1917, nineteen (of a planned twenty-one) huge mines, containing a total of over 455 tons of ammonal explosives, were set off beneath German lines on the Messines-Wytschaete ridge. The explosion, which killed about 10,000 Germans, was heard as far away as London and Dublin. While determining the power of explosions is difficult, this was probably the largest planned explosion in history until the 1945 Trinity atomic weapon test, and the largest non-nuclear planned explosion until the 1947 British Heligoland detonation (below). The Messines mines detonation killed more people than any other non-nuclear man-made explosion in history.

A view of the Halifax Explosion pyrocumulus cloud, most likely from Bedford Basin looking toward the Narrows 15-20 seconds after the explosion.

Halifax Explosion

On 6 December 1917 the SS Imo and the SS Mont-Blanc collided in the harbour of Halifax, Nova Scotia. Mont-Blanc carried 2,653 tonnes of various explosives, mostly picric acid. After the collision the ship caught fire, drifted into town, and exploded. More than 2,000 people were killed and much of Halifax was destroyed. An evaluation of the explosion's force puts it at 2.9 kilotons TNT equivalent.

Split Rock explosion

On 2 July 1918 a munitions factory near Syracuse, New York, exploded after a mixing motor in the main TNT building overheated. The fire rapidly spread through the wooden structure of the main factory. Approximately 1-3 tons of TNT were involved in the blast, which leveled the structure and killed 50 workers (conflicting reports mention 52 deaths).

T. A. Gillespie Company Shell Loading Plant explosion, or Morgan Depot Explosion

On 4 October 1918 an ammunition plant — operated by the T. A. Gillespie Company and located in the Morgan area of Sayreville in Middlesex County, New Jersey — exploded and triggered a fire. The subsequent series of explosions continued for three days. The facility, said to be one of the largest in the world at the time, was destroyed, along with more than 300 buildings forcing reconstruction of South Amboy and Sayreville. Though an exact number cannot be determined, it is believed that over 100 people died in this accident.

Interwar period

Oppau explosion

On 21 September 1921 a silo filled with 4,500 tonnes of fertilizer exploded, killing around 560, largely destroying Oppau, Germany, and causing damage more than 30 km away.

Nixon New Jersey Explosion

The 1924 Nixon Nitration Works disaster was an explosion and fire that claimed many lives and destroyed several square miles of New Jersey factories. Saturday morning, March 1, 1924, when an explosion destroyed a building in Nixon, New Jersey used for processing ammonium nitrate. The 11:15 a.m. explosion touched off fires in surrounding buildings in the Nixon Nitration Works that contained other highly flammable materials. The disaster killed twenty persons, destroyed forty buildings, and demolished the “tiny industrial town of Nixon, New Jersey.”

New London School explosion

On 18 March 1937, a natural gas leak caused an explosion destroying the New London School of the city of New London, Texas. Over 300 students and teachers died.

World War II era

Casablanca

On 13 September 1939 the French cruiser Pluton exploded and sank while offloading naval mines in the port of Casablanca, in French Morocco. The explosion killed 186 men, destroyed three nearby armed trawlers, and damaged nine more.

HMS Hood

On 24 May 1941 the battle cruiser sank in three minutes after the stern magazine detonated during the Battle of the Denmark Strait. The wreck has been located in three pieces, suggesting additional detonation of a forward magazine. There were only three survivors from the crew of 1418.

HMS Barham's main magazines explode, 25 November 1941

The magazine of Roma's number two 15-inch (381-mm) turret explodes on 9 September 1943.

HMS Barham

On 25 November 1941, the battleship rolled over after being torpedoed by U-331 and disintegrated from multiple magazine detonations attributed to inappropriately stored anti-aircraft ammunition. Film of the explosion was kept secret in deference to the 861 casualties, but has been widely viewed since the war.

USS Arizona

On 7 December 1941 during the Japanese attack on Pearl Harbor the battleship was lifted from the water when a bomb detonated in the forward magazine, killing 1,177 crewmen.

SS Surrey

On the night of 10 June 1942, U-68 torpedoed the 8600-ton British freighter Surrey in the Caribbean Sea. Five-thousand tons of dynamite in the cargo detonated after the ship sank. The shock wave lifted U-68 out of the water like a torpedo hit, and both diesel engines and the gyrocompass were disabled.

Convoy SC 107

On the night of 3 November 1942, torpedoes detonated the ammunition cargo of the 6690-ton British freighter Hatimura. Both the freighter and attacking submarine U-132 were destroyed by the explosion.

British escort carrier HMS Avenger

On 15 November 1942 the escort carrier sank with all but 12 of its 550-man crew when a torpedo fired by U-155 detonated the bomb magazine.

Japanese battleship Mutsu

While anchored near Hashirajima on 8 June 1943, the battleship was cut in two by an unexplained detonation of the magazine for #3 turret. The bow sank quickly, but the inverted stern remained afloat for 14 hours. There were 353 survivors of the 1474 aboard during the detonation.

Italian battleship Roma

On 9 September 1943 the battleship was cut in two when the magazine for the #2 turret was detonated by a German Fritz X MCLOS precision-guided munition after Italy had signed an armistice with the Allies. There were 596 survivors from a crew of 1849.

USS Liscombe Bay

On 24 November 1943 the escort carrier sank in 23 minutes with 644 of its crew when a torpedo fired by Japanese submarine I-175 detonated the bomb magazine.

Bombay Docks Explosion

On 14 April 1944 the SS Fort Stikine, carrying around 1,400 long tons (1,400 t) of explosives (among other goods), caught fire and exploded, killing around 800 people.

Bergen Harbour Explosion

On 20 April 1944 the Dutch steam trawler Voorbode, loaded with 124,000 kg of explosives, caught fire and exploded at the quay in the center of Bergen. The air pressure from the explosion and the tsunami that followed flattened whole neighborhoods near the harbor. Fires broke out in the aftermath, leaving 5,000 people homeless. 160 people were killed and 5,000 wounded.

West Loch Disaster

On 21 May 1944 an ammunition handling accident in Pearl Harbor destroyed six LSTs and 3 LCTs. Four more LSTs, ten tugs, and a net tender were damaged. Eleven buildings were destroyed ashore and nine more damaged. Nearly 400 military personnel were killed.

The explosion of the USS Mount Hood. The smoke trails are left by fragments ejected by the explosion.

The destruction of the Yamato.

Port Chicago disaster

On 17 July 1944 in Port Chicago, California, the SS E. A. Bryan exploded while loading ammunition bound for the Pacific, with an estimated 4,606 short tons (4,178 t) of high explosive, incendiary bombs, depth charges, and other ammunition. Another 429 short tons (389 t) waiting on nearby rail cars also exploded. The total explosive content is described as between 1,600 and 2,136 tons of TNT. 320 were killed instantly, another 390 wounded. Most of the killed and wounded were African American enlisted men. Following the explosion, 258 fellow sailors refused to load ordnance; 50 of these, called the "Port Chicago 50", were convicted of mutiny even though they were willing to carry out any order that did not involve loading ordnance under unsafe conditions.

Cleveland East Ohio Gas Explosion

On 2 October 1944, liquified natural gas storage tanks in Cleveland, Ohio, exploded. The explosion destroyed 1 square mile (3 km²), killed 130, and left 600 homeless.

USS Mount Hood

On 10 November 1944 the ammunition ship exploded in Seeadler Harbor at Manus Island with an estimated 3,800 tons of ordnance material on board. Mushrooming smoke rose to 7,000 feet (2000 m), obscuring the ship and the surrounding area for a radius of approximately 500 yards (500 m). Mount Hood's former position was revealed by a trench in the ocean floor 1000 feet (300 m) long, 200 feet (60 m) wide, and 30 to 40 feet (10 to 12 m) deep. The largest remaining piece of the hull was found in the trench and measured no bigger than 16 by 10 feet (5 by 3 m). All 296 men aboard the ship were killed. The USS Mindanao was 350 yards (320 m) away and suffered extensive damage, with 23 crew killed, and 174 injured. Several other nearby ships were also damaged or destroyed. Altogether 372 were killed and 371 injured in the blast.

RAF Fauld Explosion

On 27 November 1944 the RAF Ammunition Depot at Fauld, Staffordshire, became the site of the largest explosion in the UK, when 3,700 tonnes of bombs stored in underground bunkers covering 17,000 square meters exploded en masse. The explosion was caused by bombs being taken out of store, primed for use, and replaced with the detonators still installed when unused. The crater was 30 meters deep and covered 5 hectares. The death toll was approximately 78, including RAF, six Italian POWs, civilian employees, and local people. In the similar Port Chicago disaster (above), about half the weight of bombs was high explosive. If the same is true of the Fauld Explosion, it would have been equivalent to about 2 kilotons of TNT.

Japanese aircraft carrier Unryu

On 19 December 1944 the carrier disintegrated when torpedoes fired by USS Redfish detonated the forward magazine.

Japanese battleship Yamato

On 7 April 1945, after six hours of battle, the Yamato's magazine exploded as she sank, resulting in a mushroom cloud rising six kilometers above the wreck (where it could be seen from Kyushu, 160 kilometers away). 2,055 crewmen were killed.

Post World War II era

Texas City Disaster

On 16 April 1947, the SS Grandcamp, loaded with 8,500 short tons (7,700 t) of ammonium nitrate, exploded in port at Texas City, Texas. 581 died, over 5,000 injured. Using standard chemical data for decomposition of ammonium nitrate gives 2.7 kilotons of energy released. However the US Army rates the relative effectiveness factor of ammonium nitrate, compared to TNT, as 0.42. This conversion factor makes the blast equivalent to (0.42)7,770 tons, or 3.2 kilotons of TNT, with the discrepancy between the total energy and relative effectiveness value of the explosive power being due to direct comparisons between high explosives not being as simplistic as comparing total internal energy of each high explosive.

This is generally considered the worst industrial accident in United States history.

Heligoland

On 18 April 1947 British engineers attempted to destroy the entire North Sea island of Heligoland in what became known as the "British Bang". Roughly 4000 tons of surplus World War II ammunition were placed in various locations around the island and set off. The island survived, although the extensive fortifications were destroyed. According to Willmore, the energy released was 1.3×10²⁰ erg (1.3×10¹³ J), or about 3.2 kilotons of TNT equivalent. The blast is listed in the Guinness Book of World Records under largest single explosive detonation, although Minor Scale would appear to be larger.

Ocean Liberty Brest

On 28 July 1947, the Norwegian cargo ship Ocean Liberty exploded in the French port of Brest. The cargo consisted of approximately 3300 tonnes of ammonium nitrate in addition to paraffin and petrol. The explosion killed 33 people, around 1000 were injured, 4000 lighter injuries, 4000-5000 buildings were damaged.

Cadiz Explosion Cadiz

On 18 August 1947, A naval ammunition warehouse containing mostly mines and torpedoes exploded in the city of Cadiz, southern Spain, for unknown reasons. Officially, the explosion of approximately 200 tons of TNT, which leveled a large portion of the city, killed 150 people however the real death toll is suspected to be considerably higher.

Kalvarienberg Prüm

On 15 July 1949 in the German town of Prüm, a bunker used previously by the German army to store ammunition caught fire. After a mostly successful evacuation of the town the 500 tonnes ammunition in the bunker exploded and destroyed large parts of the town. 12 people died and 15 were severely injured.

Cali Explosion, Colombia

On 7 August 1956 seven trucks from the Colombian army, carrying more than 40 tons of dynamite, exploded, killing more than 1000 people and leaving a crater 25 meters (70 ft) deep and 60 meters (200 ft) in diameter.

Ripple Rock, Canada

On 5 April 1958 an underwater mountain was leveled by the explosion of 1,375 tonnes of Nitramex2H, an ammonium nitrate–based explosive.

Operation Blowdown

On 18 July 1963, a joint UK-Australian test in the Iron Range area of Queensland, Australia, tested the feasibility of nuclear weapons for clearing forests and using mangled forests to slow troop movement in South East Asia, primarily Indonesia and Malaysia in the escalation against Sukarno and the Konfrontasi Malayan Emergency and with a view to the later Myanmar conflict and Vietnam War simmering at the time.

CHASE 2, off New Jersey

On 17 September 1964, offshore disposal of the ship Village, containing 7,348-short-ton (6,666 t) of obsolete munitions, caused unexpected detonations 5 minutes after sinking. The detonations were detected on seismic instruments around the world, and encouraged intentional detonation of subsequent disposal operations to determine detectability of underwater nuclear testing.

500 short tons (450 t) tons of HE awaiting detonation for Operation Sailor Hat

Detonation of explosive during Operation Sailor Hat, with shock front visible moving across the water and shock condensation cloud visible overhead

Operation Sailor Hat, off Kaho'olawe Island, Hawaii

A series of tests was performed in 1965, using conventional explosives to simulate the shock effects of nuclear blasts on naval vessels. Each test saw the detonation of a 500-short-ton (450 t) mass of high explosives.

CHASE 3 and 4, off New Jersey

On 14 July 1965, Coastal Mariner was loaded with 4,040-short-ton (3,670 t) of obsolete munitions containing 512-short-ton (464 t) of high explosives. The cargo was detonated at a depth of 1,000 feet (300 m) and created a 600-foot (200 m) water spout, but was not deep enough to be recorded on seismic instruments. On 16 September 1965, Santiago Iglesias was similarly detonated with 8,715-short-ton (7,906 t) of obsolete munitions.

Medeo Dam, near Alma-Ata, Kazakhstan

On 21 October 1966 a mud flow protection dam was created by a series of four preliminary explosions of 1,800 tonnes total and a final explosion of 3,600 tonnes of ammonium nitrate–based explosive. On 14 April 1967 the dam was reinforced by an explosion of 3,900 tonnes of ammonium nitrate–based explosive.

CHASE 5, off Puget Sound

On 23 May 1966, Izaac Van Zandt was loaded with 8,000-short-ton (7,300 t) of obsolete munitions containing 400-short-ton (360 t) of high explosives. The cargo was detonated at a depth of 4000 feet (1.2 km).

CHASE 6, off New Jersey

On 28 July 1966, Horace Greeley was loaded with obsolete munitions and detonated at a depth of 4000 feet (1.2 km).

N1 launch explosion

On 3 July 1969, an N1 rocket in the Soviet Union exploded on the launch pad, after a loose bolt was ingested into a fuel pump. The entire rocket contained about 680,000 kg (680 t) of kerosene and 1,780,000 kg (1,780 t) of liquid oxygen. Using a standard energy release of 43 MJ/kg of kerosene gives about 29 TJ for the energy of the explosion (about 6.93 kt TNT equivalent). Comparing explosions of initially unmixed fuels is difficult (being part detonation and part deflagration), but in terms of energy released, this is the largest man-made non-nuclear explosion, not detonation.

Los Alfaques disaster

On July 11, 1978, an over-loaded tanker truck carrying 23 tons of liquefied propylene crashed and ruptured in Spain, emitting a huge white cloud of ground-hugging fumes which spread into a nearby campground and discotheque before reaching an ignition source and exploding. 217 people were killed and 200 more severely burned.

Minor Scale and Misty Picture

Many very large deliberate detonations have been carried out in order to simulate the effects of nuclear weapons on vehicles and military material in general. The largest publicly known test was conducted by the United States Defense Nuclear Agency (now part of the Defense Threat Reduction Agency) on 27 June 1985 at the White Sands Missile Range in New Mexico. This test, called Minor Scale, used 4744 short tons of ANFO, with a yield of about 4 kt. Misty Picture was another similar test a few years later, just slightly smaller (4,685 short tons or 4,250 t).

Murdock BLEVEs

In 1983 near Murdock, Illinois, at least two tanker cars of a burning derailed train exploded into massive BLEVEs; one of them was hurled nearly three-quarters of a mile as a consequence.

PEPCON disaster

On 4 May 1988 about 8,500,000 lb (3,900 t) of ammonium perchlorate burned in a fire and set of massive explosions near Henderson, Nevada. In addition to the ammonium perchlorate a 16 inch natural gas pipeline which was below the stored ammonium perchlorate was ruptured and added fuel to the later, larger explosions. There were seven detonations total, the largest being the last. Two people were killed and hundreds injured. The largest explosion was estimated to be equivalent to a 1.5 million pound detonation of TNT.¹ The accident was caught on video by a broadcast engineer servicing a transmitter on a nearby mountaintop.

Ufa train disaster

On 4 June 1989, a gas explosion destroyed two trains in the Soviet Union.

Intelsat 708 Long March 3B launch failure

On February 14, 1996, a Chinese rocket veered severely off course immediately after clearing the launch tower, then crashed into and incinerated a nearby city in an enormous explosion. Following the disaster, foreign media were sequestered in a bunker for five hours while, some alleged, the Chinese military attempted to "clean up" the damage. Officials later blamed the failure on an "unexpected gust of wind" (video shows this is clearly not the case). Xinhua News Agency initially reported 6 deaths and 57 injuries.

Enschede fireworks disaster

On 13 May 2000 about 177 tonnes of fireworks exploded in the Dutch town of Enschede, in which 23 people were killed and 947 were injured. The first explosion had strength in the order of 800 kg TNT equivalence, while the strength of the final explosion was within the range of 4000–5000 kg TNT.

2001–present

2001 AZF chemical factory explosion in Toulouse, France

On 21 September 2001 the disaster caused 29 deaths, 2,500 seriously wounded, and 8,000 light casualties. The blast (estimated yield of 20-40 tons of TNT, comparable in scale to the military test Operation Blowdown) was heard 80 km away (50 miles) and registered 3.4 on the Richter scale and damaged about 30,000 buildings over about two thirds of the city, for an estimated total cost of about €2 billions.

Ryongchon disaster

A train explosion in North Korea on 22 April 2004; according to official figures, 54 people were killed and 1,249 were injured.

Seest fireworks disaster

On 3 November 2004 about 800 tonnes of fireworks exploded in the Danish town of Kolding. One firefighter was killed, and a mass evacuation - 2,000 people left - saved many lives. The cost of the damage was estimated at €100 million.

2005 Hertfordshire Oil Storage Terminal fire

On 11 December 2005 there was a series of major explosions at the 60,000,000 imp gal (270,000,000 L) capacity Buncefield oil depot near Hemel Hempstead, Hertfordshire, England. The explosions were heard over 100 mi (160 km) away, as far as the Netherlands and France, and the resulting flames were visible for many miles around the depot. A smoke cloud covered Hemel Hempstead and other nearby towns in west Hertfordshire and Buckinghamshire. There were no fatalities, but there were around 43 injuries (two serious).

Sea Launch failure

On 30 January 2007, a Sea Launch Zenit-3SL rocket exploded on takeoff. The explosion consumed the roughly 400,000 kg (400 t) of kerosene and liquid oxygen on board. This rocket was launched from an uncrewed ship in the middle of the Pacific ocean, so there were no casualties; the launch platform was damaged and the NSS-8 satellite was destroyed.

Toronto propane explosion

On August 10, 2008, a fire in a propane storage facility near Toronto, Canada caused at least one large BLEVE explosion whose shock wave shattered windows throughout the Downsview suburb.

T2 Laboratories

On 19 December 2007, T2 Laboratories in Jacksonville Florida exploded with the power of 1 ton of TNT. It left 4 people dead and 14 injured. The explosion occurred in a 2500 gallon batch reactor during production of methylcyclopentadienyl manganese tricarbonyl. The reactor cooling system, which lacked backups, failed; this led to a thermal runaway.

2009 Cataño oil refinery fire

On the morning of 23 October 2009 there was a major explosion at the gasoline tanks at the Caribbean Petroleum Corporation oil refinery and oil depot in Bayamón, Puerto Rico, that was seen and heard from 50 miles (80 km) away and left a smoke plume with tops as high as 30,000 feet (9 km), caused a 3.0 earthquake and blew glass around the city. The resulting fire was extinguished on 25 October.

Ulyanovsk arms depot explosion

On 13 and 23 November 2009, 120 tons of Soviet-era artillery shells blew up in two separate sets of explosions at the 31st Arsenal of the Caspian Sea Flotilla's ammunition depot near Ulyanovsk, killing ten.

Evangelos Florakis Naval Base explosion

At around 5:45 am local time of 11 July 2011, a fire at a munitions dump at Evangelos Florakis Naval Base near Zygi, Cyprus, caused the explosion of 98 cargo containers of various types of munition, causing the equivalent of 2 kilotons of TNT equivalent energy to be released, destroying the naval base along with Cyprus biggest power plant, "Vassilikos" power plant 500 m away, and causing the death of 13 and injuries to over 60. Injuries were reported up to 5 km and damaged houses were reported as far as 10 km from the ground zero. Seismometers at the Mediterranean region recorded the explosion as a M3.0 seismic event.

Cosmo Oil Refinery Fire

The Cosmo Oil Company's refinery in Japan's Ichihara, Chiba Prefecture caught fire during the 2011 Tōhoku earthquake. As it raged, several pressurized liquified propane gas storage tanks BLEVE'd into massive fireballs.

Hunan LNG tanker explosion

On October 6, 2012, a derailed tanker car filled with 20 tons of liquified natural gas ruptured, causing a white gas cloud to expand for 25 seconds across an adjacent highway before reaching an ignition source, resulting in an explosion and shock-wave which killed five and demolished two fire engines.

Texas fertilizer plant explosion

On April 17, 2013, a fire culminating in an explosion shortly before 8 p.m. CDT (00:50 UTC, April 18) destroyed the West Fertilizer Company plant in West, Texas, 18 miles (29 km) north of Waco, Texas. The blast killed 15 people, injured over 160, and destroyed over 150 buildings. The United States Geological Survey recorded the explosion as a 2.1-magnitude earthquake.

Comparison with large conventional military ordnance

The most powerful non-nuclear weapons ever designed are the United States' MOAB (standing for Massive Ordnance Air Blast, also nicknamed Mother Of All Bombs, tested in 2003) and the Russian Father of All Bombs (tested in 2007). The MOAB contains 18,700 lb (8.5 t) of the H6 explosive, which is 1.35 times as powerful as TNT, giving the bomb an approximate yield of 11 t. The FOAB is about 4 times more powerful than the MOAB. It would require about 250 MOAB blasts to equal the Halifax Explosion.

Conventional explosions for nuclear testing

A number of large conventional explosions have been conducted for nuclear testing purposes. Some of the larger ones are listed below.

Event	Explosive used	Amount of explosive	Where	Date
Trinity calibration test	TNT	108 tons	White Sands Proving Grounds	7 May 1945
Operation Blowdown	TNT	50 short tons (45 t)	Lockhart River, Queensland	18 July 1963
Snowball	TNT	500 short tons (450 t)	Alberta, Canada	1964
Operation Sailor Hat	TNT	3 tests × 500 short tons (450 t)	Kahoolawe, HI	1965
Distant Plain	propane	20 short tons (18 t)	Alberta, Canada	1966-67
Prairie Flat	TNT	500 short tons (450 t)	Alberta, Canada	1968
Dial Pack	TNT	500 short tons (450 t)	Alberta, Canada	23 July 1970
Mixed Company	TNT	500 short tons (450 t)	Colorado	20 November 1972
Dice Throw	ANFO	620 short tons (560 t)	White Sands Missile Range	6 October 1976
Misers Bluff	ANFO	7 tests × 120 short tons (110 t)	Planet Ranch, AZ	1978
Distant Runner	ANFO	2 tests × 120 short tons (110 t)	White Sands Missile Range	1981
Mill Race	ANFO	620 short tons (560 t)	White Sands Missile Range	16 September 1981
Direct Course	ANFO	609 short tons (552 t)	White Sands Missile Range	26 October 1983
Minor Scale	ANFO	4,744 short tons (4,304 t)	White Sands Missile Range	27 June 1985
Misty Picture	ANFO	4,685 short tons (4,250 t)	White Sands Missile Range	14 May 1987
Misers Gold	ANFO	2,445 short tons (2,218 t)	White Sands Missile Range	1 June 1989
Distant Image	ANFO	2,440 short tons (2,210 t)	White Sands Missile Range	20 June 1991
Minor Uncle	ANFO	2,725 short tons (2,472 t)	White Sands Missile Range	10 June 1993
Non Proliferation Experiment	ANFO	1,410 short tons (1,280 t)	Nevada Test Site	22 September 1993

Other smaller tests include Pre Mine Throw and Mine Throw in 1970-1974, Pre Dice Throw and Pre Dice Throw II in 1975, Pre-Direct Course in 1982, SHIST in 1994, and the series Dipole Might in the 1990s and 2000s. Divine Strake was a planned test of 700 tons at the Nevada Test Site in 2006, but was cancelled.

Rank order of largest conventional explosions/detonations by magnitude

These yields are approximated by the amount of the explosive material and its properties. They are rough estimates and are not authoritative. For example, neglecting the fact that even properly mixed LOX fuel mixture explosions have a lower power density value and relative effectiveness factor than TNT, the July 3, 1969 N1 launch vehicle explosion was, assuming all available fuel was burnt at optimum efficiency, in an energy comparison only, that is, not on a power comparison basis, equivalent to approximately 7,000 tons of TNT in a joule to joule comparison of released energy. Moreover this 29 TJ energy figure in of itself is also idealized, being based on assuming that all of the available rocket fuel was burnt at optimal efficiency, with no black soot production in the explosion, soot that is in reality visible in the historical video recordings of the explosion.

Event	Approximate yield
N1 launch explosion, which unlike the following events, was not a High Explosive detonation	3-7 kt of TNT (12-29 TJ)
Minor Scale and Misty Picture	4 kt of TNT (17 TJ)
Heligoland	3.2 kt of TNT (13 TJ)
Halifax Explosion	2.9 kt of TNT (12 TJ)
Texas City Disaster	2.7-3.2 kt of TNT (11–13 TJ)
Evangelos Florakis Naval Base explosion	2-3.2 kt of TNT (9–13 TJ)
Port Chicago disaster	1.6-2.2 kt of TNT (7–9 TJ)

External links

• Statistics and information. Interactive model.
• 1:54 onwards contains footage from a Soviet N-1 Moon Rocket documentary showing the July 3 1969 N1 exploding seconds after taking flight.

See also

• List of nuclear tests
• List of accidents and disasters by death toll