There have been many extremely large explosions, accidental and intentional, caused by modern high explosives, boiling liquid expanding vapor explosions (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).
On 4 April 1585, during the Spanish siege of Antwerp, a fortified bridge named "Puente Farnesio" had been built by the Spanish on the Scheldt river, in order to isolate the city from reinforcement. With the purpose of breaking the bridge, the Dutch designed four large fire ships, filled with gunpowder and rocks. Three of the fire ships failed to reach the target, but one of 800 tons struck the bridge. It did not explode immediately, which gave time for some curious Spaniards to board her. There was then a devastating blast that killed 800 Spaniards on the bridge, throwing bodies, rocks and pieces of metal a distance of several kilometers. A small tsunami arose in the river, the ground shook for miles around and a large, dark cloud covered the area. The blast was felt as far as 35 km away in Ghent, where windows vibrated.
On 16 February 1646, 80 barrels (5.72 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.
On 26 September 1687, the famous and until-then-intact Greek monument was partially destroyed when an Ottoman ammunition bunker inside was struck by a Venetian mortar. 300 Turkish soldiers were killed in the explosion.
In 1769, the Bastion of San Nazaro in 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.
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 powder magazine. It ignited 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.
On 30 December 1848, in Multan during the Second Anglo-Sikh War, 180 000 kg of gunpowder [200 short tons (180 t)] was being stored in a mosque when a mortar shell hit it, causing an explosion and many casualties.
On 4 April 1856, the Ottomans had stored a large amount of gunpowder in the palace and the adjacent church, which were also full of people. At the time, it was considered that the ringing of bells could prevent the formation of storms. A lightning bolt hit the gunpowder, triggering a blast that killed 4,000 people.
On 10 October 1885 in New York City, the U.S. Army Corps of Engineers detonated 300,000 pounds 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 250 feet 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 into a single island, Mill Rock.
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 broken.
On 15 October 1907, approximately 40,000 kegs of powder exploded in the city of Fontanet, Indiana, killing between 50 and 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.
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. 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.
On 26 November 1914, the British pre-dreadnought battleship HMS Bulwark suffered an explosion amidships and sank near Sheerness, Kent. An estimated 736 men died. Two of the 14 survivors later died in hospital. Other crew were ashore at the time of the explosion. An inquiry investigated various theories including the overheating of older cordite cartridges or their mishandling. Survivors reported some charges were out of the magazine and were being stored in a passageway that morning, under Royal Marine guard. The explosion occurred around breakfast when smoking was normally allowed.
HMS Princess Irene at Sheerness
On 27 May 1915 the converted minelayer HMS Princess Irene suffered a blast described as larger than that of HMS Bulwark (see above) but with fewer casualties. Wreckage was thrown up to 20 miles while a collier ship half a mile away had its crane blown off and a crew member was killed by a fragment weighing 70 pounds. A child ashore was killed by another fragment. A case of butter was found six miles away. A total of 352 people were killed but one crew member survived, with severe burns. The ship had been loaded with 300 sea mines containing more than 150 tons of high explosive. An inquiry blamed faulty priming, possibly by untrained personnel.
On 30 December 1915 the British armored cruiser HMS Natal was anchored in Cromarty Firth, Scotland. The captain was hosting a film party aboard and there were wives, nurses and children aboard. A series of explosions occurred astern which resulted in the ship capsizing and sinking in shallow water within five minutes. Estimates of the death toll vary from 390 to 421. Faulty or over-age cordite was blamed for the loss. A similar suggestion was made for HMS Bulwark. Royal Navy cordite safety was improved with greater attention to temperature and age but cordite was also implicated in the explosive losses of ships at the Battle of Jutland in 1916.
On 2 April 1916, an 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, and 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.
On 31 May 1916, three British battlecruisers were destroyed by cordite deflagrations initiated by armor-piercing shells fired by 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 two of her crew of 1,019. German eyewitness reports and the testimony of modern divers suggest all her magazines exploded. The wreck is now a debris field. 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. As the rear section capsized it also exploded. At 18:30 HMS Invincible was cut in two by detonation of the midships magazine and sank in 90 seconds with all but six of her crew. 1026 men died including Rear Admiral Hood. An armored cruiser, HMS Defence, was a fourth ship to suffer an explosive deflagration at Jutland with at least 893 men killed. The rear magazine was seen to detonate followed by more explosions as the cordite flash traveled along an ammunition passage beneath her broadside guns. Eye witness reports suggest that HMS Black Prince may also have suffered an explosion as she was lost during the night action with all hands - 857 men. British reports say she was seen to blow up. German reports speak of the ship being overwhelmed at close range and sinking.
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.
On 30 July 1916, sabotage by German agents caused 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, to explode in Jersey City, New Jersey, a major dock serving New York. There were few deaths, but about 100 injuries. Damage included buildings on Ellis Island, parts of the Statue of Liberty, and much of Jersey City.
On 19 January 1917, parts of Silvertown in East London were devastated by a 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).
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.
On 7 June 1917, nineteen (of a planned twenty-one) large 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.
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.
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).
On 9 July 1917 the British dreadnought battleship HMS Vanguard suffered a violent explosion amidships and sank in Scapa Flow anchorage. A fire is thought to have 'cooked off' cordite ammunition in an adjacent compartment. An estimated 804 men died with only two survivors.
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. Over 100 people died in this accident.
1939 Japanese Imperial Army ammunition dump exploded in Hirakata, Osaka, Japan
The 1924 Nixon Nitration Works disaster was an explosion and fire that claimed many lives and destroyed several square miles of New Jersey factories. On 1 March 1924, an explosion destroyed a building in Nixon, New Jersey used for processing ammonium nitrate. The explosion touched off fires in surrounding buildings in the Nixon Nitration Works that contained other highly flammable materials. The disaster killed twenty and destroyed forty buildings.
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.
Hirakata ammunition dump explosion
On 1 March 1939, Warehouse No. 15 of the Japanese Imperial Army's Kinya ammunition dump in Hirakata, Osaka Prefecture, Japan, suffered a catastrophic explosion, the sound of which could be heard throughout the Keihan area. Additional explosions followed over the next few days as the depot burned, for a total of 29 explosions by 3 March. Japanese officials reported that 94 people died, 604 were injured, and 821 houses were damaged, with 4,425 households in all suffering the effects of the explosions.
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.
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.
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.
On the night of 10 June 1942, U-68torpedoed 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.
On the night of 3 November 1942, torpedoes detonated the ammunition cargo of the 6690-ton British freighter Hatimura. Both the freighter and attacking submarineU-132 were destroyed by the explosion.
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.
Naples Caterina Costa explosion
On 28 March 1943 in the port of Naples a fire broke out on Caterina Costa, an 8,060 ton motor ship with arms and supplies (1,000 tons of gas, 900 explosives, tanks and others); the fire became uncontrollable, causing a devastating explosion. A large number of buildings around were destroyed or badly damaged. Some ships nearby caught fire and sank while hot parts of the ship and tanks were thrown at great distance. More than 600 dead and over 3,000 wounded.
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.
On 9 September 1943 the battleship was cut in two when the magazine for the #2 turret was detonated by a German Fritz XMCLOSprecision-guided munition after Italy had signed an armistice with the Allies. There were 596 survivors from a crew of 1849.
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.
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.
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.
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.
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.
Sunk by a kamikaze attack on 28 December 1944 off the coast of the Philippines. The impact of the airplane ignited the John Burke's cargo of ammunition and explosives, resulting in a blast that destroyed the ship and killed all 68 crewmen.
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, and which could be seen from Kyushu, 160 kilometers away). 2,055 crewmen were killed.
On May 7, 1945 100 tons of TNT was stacked on a wooden tower and exploded to test the instrumentation prior to the test of the first atomic bomb.
Post World War II era
Futamata Tunnel Explosion
On 12 November 1945, When the occupation troops are trying to dispose of ammunition of 530 tons, following to explosion into tunnel in Soeda, Fukuoka Prefecture, Kyushu Island. According to official confirmed report, killing 147 local residents and injuring 149 person.
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 makes this equivalent to 2.7 kilotons of TNT exploding.[Note 1] 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.
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 was larger.
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 22 people, hundreds were injured, 4000-5000 buildings were damaged.
On 18 August 1947, a naval ammunition warehouse containing mostly mines and torpedoes exploded in Cádiz, in southern Spain, for unknown reasons. The explosion of approximately 200 tons of TNT leveled a large portion of the city. Officially, the explosion killed 150 people; the real death toll is suspected to be higher.
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, the 500 tonnes of ammunition in the bunker exploded and destroyed large parts of the town. 12 people died and 15 were severely injured.
On September 23, 1955 in the Mexican city of Gómez Palacio, Durango, two trucks charged with 15 tons of dynamite exploded when apparently collided with a passenger train, causing many deaths.
Cali Explosion, Colombia
On 7 August 1956 seven trucks from the Colombian army, carrying more than 40 tons of dynamite, exploded. The explosion killed more than 1000 people, and left a crater 25 meters (70 ft) deep and 60 meters (200 ft) in diameter.
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 KonfrontasiMalayan Emergency.
On 17 September 1964, the 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; the incident encouraged intentional detonation of subsequent disposal operations to determine detectability of underwater nuclear testing.
500 short tons (450 t) tons of high explosives 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
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.
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.
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).
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.
On 1 June 1974, a pipe failure at the Nypro chemical plant in Flixborough, England, caused a large release of flammable cyclohexane vapour. This ignited and the resulting fuel-air explosion destroyed the plant, killing 28 people and injuring 36 more. The explosion occurred on a weekend otherwise the casualties would have been much heavier. This explosion caused a significant strengthening of safety regulations for chemical process plants in the United Kingdom.
On 11 November 1977, a freight train carrying 40 tons of dynamite from Incheon to Gwangju suddenly exploded at Iri station (present-day Iksan), Jeollabuk-do province, South Korea. The cause of the explosion was accidental ignition by an intoxicated guard. 59 people lost their lives, and 185 others seriously wounded; altogether, over 1,300 people were injured or killed.
On 11 July 1978, an overloaded tanker truck carrying 23 tons of liquefied propylene crashed and ruptured in Spain, emitting a white cloud of ground-hugging fumes which spread into a nearby campground and discothèque before reaching an ignition source and exploding. 217 people were killed and 200 more severely burned.
In June 1982, the Siberian Oil Pipeline in the USSR is alleged to have exploded because of CIA sabotage: The story as it appears in a book by Thomas C. Reed is that an electronic Trojan Horse had been added to the pipelines control software before it was "stolen" from a Canadian firm by the KGB for use on the pipeline. When the trojan horse was triggered, it caused widespread equipment malfunction. Details were classified, but former Air Force secretary Thomas C. Reed describes it as being "the most monumental non-nuclear explosion and fire ever seen from space." The Soviets/Russians deny the massive explosive event ever occurred, leaving corroboration of the story difficult without attaining the alleged photographs from space.
Many very large deliberate detonations have been carried out in order to simulate the effects of nuclear weapons on vehicles and other military material. 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 at (4,685 short tons or 4,250 t).
On 27 May 1983 an explosion at an illegal fireworks factory near Benton, Tennessee killed eleven, injured one, and caused damage within a radius of several miles. The blast created a mushroom cloud 600 to 800 feet tall and was heard as far as fifteen miles away.
On 4 May 1988 about 8,500,000 lb (3,900 t) of ammonium perchlorate burned in a fire and set off explosions near Henderson, Nevada. A 16 inches (41 cm) natural gas pipeline ruptured under the stored ammonium perchlorate and added fuel to the later, larger explosions. There were seven detonations in total, the largest being the last. Two people were killed and hundreds injured. The largest explosion was estimated to be equivalent to one kiloton of TNT. The accident was caught on video by a broadcast engineer servicing a transmitter on a nearby mountaintop.
On 14 February 1996, a Chinese rocket veered severely off course immediately after clearing the launch tower, then crashed into a nearby city and exploded. Following the disaster, foreign media were kept 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" although video shows this is not the case. Xinhua News Agency initially reported 6 deaths and 57 injuries.
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 the order of 800 kg TNT equivalence; the final explosion was in the range of 4000–5000 kg TNT.
On 21 September 2001 an explosion occurred at a fertilizer factory in Toulouse, France. 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. It damaged about 30,000 buildings over about two-thirds of the city, for an estimated total cost of about €2 billions.
On 3 November 2004 about 284 tonnes of fireworks exploded in the Danish town of Kolding. One firefighter was killed, and a mass evacuation of 2,000 people saved many lives. The cost of the damage was estimated at €100 million.
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 (2 serious).
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.
On 22 March 2007, a series of explosions over 2.5 hours rocked the Mozambican capital of Maputo. The incident was blamed on high temperatures. Officials confirmed 93 fatalities and more than 300 injuries.
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.
On the morning of 23 October 2009 there was a major explosion at the gasoline tanks at the Caribbean Petroleum Corporationoil refinery and oil depot in Bayamón, Puerto Rico. The explosion 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)/ It caused a 3.0 earthquake and blew glass around the city. The resulting fire was extinguished on 25 October.
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.
On 6 October 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. The resulting explosion and shock wave killed five and demolished two fire engines.
On 17 April 2013, a fire culminating in an explosion shortly before 8 p.m. CDT (00:50 UTC, 18 April) destroyed the West Fertilizer Company plant in West, Texas, located 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.
On 7 July 2013, a train of 72 tank cars of light crude oil ran away down a slight incline, after being left unattended for the night, when the air brakes failed after the locomotive engines were shut down following a small fire. It derailed twelve kilometres away in the town of Lac-Mégantic, Quebec, Canada, igniting the spilled oil and creating a blast equivalent to 900 tons of TNT that killed 42 people with five more missing presumed dead. 
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 TNT. 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.
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.
^First NH4NO3 → N2O + 2H2O + 36 kJ/mole, followed by N2O → N2 + ½O2 + 82 kJ/mole of N2O. This gives a total of 118 kJ for 80 grams of NH4NO3, or 1475 kJ/kg. Since a kiloton is defined as 4184 kJ/kg, each kiloton of NH4NO3 gives 0.35 kilotons of explosive power. So 7,700 tonnes is about 2.7 kilotons explosive.
^Jay White (1994). "Exploding Myths: The Halifax Explosion in Historical Context". In Alan Ruffman, Colin D. Howell. Ground Zero: A Reassessment of the 1917 explosion in Halifax. Nimbus Publishing. pp. 266, 292. ISBN978-1551090955.
^David Simpson and Alan Ruffman (1994). "Explosions, Bombs and Bumps: Scientific Aspects of the Explosion". In Alan Ruffman, Colin D. Howell. Ground Zero: A Reassessment of the 1917 explosion in Halifax. Nimbus Publishing. p. 288. ISBN978-1551090955.
^The Star-Ledger (Newark, New Jersey). Bridget Malone and Sue Epstein. For 3 days, the ground shook in South Amboy. 4 October 1998
^China Monthly Review88. Millard Publishing Company, Incorporated. 1939. p. 134. Held responsible for the explosion that wrecked the Hirakata munitions depot, north of Osaka, on March 1, two high Army officers were placed on the reserve list, while a captain was suspended from his duties by the War Office, Domei reported.
^Cowley, R Adams; Edelstein, Sol; Silverstein, Martin Elliot (1982). Mass Casualties, a Lessons Learned Approach: Accidents, Civil Disorders, Natural Disasters, Terrorism. U.S. Department of Transportation, National Highway Traffic Safety Administration. p. 305.
^United States Congress Senate Committee on Appropriations (1960). Hearings. University of Michigan. p. 543. On July 15, 1949, one-third of the people of Prum in Germany lost their homes when ammunition stored in a large concrete pillbox exploded and covered the hillside with debris.
^Select Committee of the United States House of Representatives (3 January 1999). "Satellite Launches in the PRC: Loral". U.S. National Security and Military/Commercial Concerns with the People's Republic of China. Retrieved 23 May 2012.