9 of the world's worst industrial disasters

At least 50 people were killed and hundreds injured in a series of massive explosions at a warehouse where hazardous chemicals were stored in the Chinese port of Tianjin on Wednesday. The cause is not yet known, but the tragedy is the latest in a long and bloody history of industrial disasters that have killed thousands of people.

• Tianjin, China, explosions: 50 dead, more than 700 injured

Here is a look at some of the disasters:

Chornobyl

The worst nuclear power plant disaster in history happened on April 26, 1986, when an explosion at Reactor 4 of Ukraine's Chornobyl power plant spewed a cloud of radioactivity over Europe and the Soviet Union.

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The explosion killed 31 people, but the long-term effects are still unknown. About 4,000 people, most of whom were children in 1986, developed thyroid cancer as a result of the incident. The United Nations estimated the death toll had climbed to 56 in 2005.

Halifax explosion

The deadliest industrial disaster in Canada happened on on Dec. 6, 1917, when a French cargo ship loaded with wartime explosives collided with a Norwegian vessel in the Halifax Harbour, causing a massive explosion that devastated Halifax.

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About 2,000 people were killed and more than 9,000 injured by debris, fires and collapsing buildings.

Centralia mining disaster

On March 25, 1947, a coal mine near Centralia, Ill., exploded and killed 111 people. It happened when an explosive detonation ignited coal dust.

The disaster prompted the U.S. Congress to enact more comprehensive safety regulations, including regular inspections, in America's coal mines.

It was also the inspiration for folksinger Woody Guthrie's song, The Dying Miner.

Bhopal disaster

Early on Dec. 3, 1984, a pesticide plant run by Union Carbide in Bhopal, India, spewed about 36 tonnes of deadly methyl isocyanate gas into the city's air, quickly killing about 4,000 people, according to local government estimates.

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Activists insist the real number is almost twice that, and say the company and government have failed to clean up toxic chemicals at the plant, which closed after the incident.

Lac-Mégantic

On July 6, 2013, an MM&A train carrying 72 tankers full of oil derailed and exploded in the town of Lac-Mégantic, Que., killing 47 people and destroying much of the town's downtown core. The victims were mostly identified by DNA samples and dental records.

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Six people employed by the rail company at the time of the incident, including its president, are facing two charges each of failing to ensure the train was properly braked before it was left unmanned for the night.

Phillips disaster

On Oct. 23, 1989, a series of explosions killed 23 people and injured 314 at the Phillips Petroleum Company  plant in Pasadena, Texas.

The blasts were sparked by an ethylene leak, which the U.S. Occupational Safety and Health Administration  blamed on inadequate safety procedures.

Rana Plaza collapse

More than 1,100 workers died and about 2,500 were injured on April 24, 2013, when the dangerously built eight-storey Rana Plaza garment factory in Dhaka, Bangladesh, collapsed.

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The tragedy drew international attention on the poor working conditions in Bangladesh, where much of the world's big brands make their clothes. It led to unprecedented change, including widespread safety inspections, wage increases and the legalization of labour unions.

Benxi colliery disaster

The April 26, 1942, gas and coal dust explosion inside a Japanese-run, forced-labour mine in Benxi, China, is believed to be the deadliest coal mining disaster in history. More than 1,549 Chinese workers, many of them prisoners of war, were killed.

Oppau explosion

On Sept. 21, 1921, a tower silo storing 4,500 tonnes of anammonium sulfate/ammonium nitrate fertilizer mixture exploded at the BASF plant in Oppau, now part of Ludwigshafen, Germany. Death toll estimates vary, but between 500 and 600 people were killed, and 2,000 injured.