--- title: "History's Deadliest Manmade Disasters..." description: "When we think about deadly disasters, the first things that come to mind tend to be things like earthquakes, volcanoes, and hurricanes. But there are some types of disasters that could only be caused by humans. And whether it's failing dams wiping out millions of homes in a single day or clouds of poisonous gas descending upon heavily populated cities, the deadliest manmade disasters have always been completely preventable.\n\n## Porto Boat Bridge Disaster\n\nIf you ever visit Porto, the second largest city in Portugal, you can take an hour long boat ride called The Six Bridges Cruise. As you might guess from the name, this cruise offers a beautiful view of Porto's six bridges that cross the Douro River, as well as providing history about the bridges.\n\nHowever, that history does not go back nearly as far as you might assume, as there was no bridge across the river until the early 1800s. Before then, people primarily relied on boats and rafts to cross the river. If special circumstances, like a festival, were going to require a great deal of travel across the river in a short period of time, then a temporary pontoon bridge would be constructed for the event, but these instances were rare and short lived.\n\nIt wasn't until 1806 that the first permanent pontoon bridge was built across the river to connect Porto and Vila Nova de Gaia. Unfortunately for the Portuguese, the following year Napoleon decided that they should be part of France now. The French were able to invade and occupy Portugal with the aid of Spain, but then Napoleon pissed off the Spanish, resulting in the Peninsular War with France fighting against the coalition of Portugal, Spain, and the United Kingdom.\n\nNapoleon's forces were driven out of Portugal in 1808, but in early 1809 he decided he wanted to have another go at it. The First Battle of Porto took place on March 28, 1809. Although the French were outnumbered, the Portuguese were outgunned, inexperienced, and disorganized. This led to a French victory in Porto, with the Portuguese soldiers fleeing across the bridge towards Gaia.\n\nBut it wasn't just soldiers trying to flee, as Marshal General Jean-de-Dieu Soult had given the French troops permission to pillage the city of Porto for the next three days. This caused people to flee the city by the thousands, taking what they could and fleeing towards Gaia.\n\nThe reason for what happened next isn't entirely clear, with there being three different explanations for what caused the disaster. Any or all of the following could have happened: Portuguese soldiers fleeing the French may have sabotaged parts of the bridge, after crossing the bridge the soldiers may have opened the middle of the bridge (as it was designed to open and allow boats to pass through), or the bridge may have collapsed from the sheer weight of the thousands of people trying to cross.\n\nThough we can't say for sure which or how many of those three things happened, we know that thousands of people fell from the bridge to their deaths. Large sections of the bridge were destroyed and needed to be repaired following the disaster, though it's hard to know whether it was only from the weight of all of the people fleeing at once or if the bridge had been sabotaged (especially since the bridge was fully dismantled in 1843, so it can't be analyzed with newer technology).\n\nWorse still, some of the civilians who fell off that bridge were already dead before they fell. The French had been pursuing the Portuguese across the bridge, and the two armed forces continued to fire upon one another even though their shots were obstructed by the thousands of fleeing civilians. Some soldiers were wounded or killed in these volleys, but it was mostly just civilians being killed by both armies. Portuguese cavalry had also killed civilians with their swords in an attempt to clear a path for their horses, horses who also trampled fallen civilians to death.\n\nWhile we didn't want to include acts of war while discussing manmade disasters, the vast majority of civilian deaths in this disaster were the result of the collapsing bridge rather than being killed by soldiers, even if war was the direct cause of the bridge being overloaded with civilians. Though exact numbers aren't known, all estimates put the total number of lives lost at around 4,000, making this the deadliest bridge disaster in history.\n\n## MV Doña Paz Ferry Disaster\n\nThe sinking of the RMS Titanic is, by far, the most famous maritime disaster to ever occur during peacetime. At the time it was also the deadliest, with just over 1,500 dead, but it has since fallen into a very distant third thanks to events that unfolded on December 20, 1987, in the Philippines.\n\nThe MV Doña Paz was a ferry with a maximum capacity of 1,518 passengers. On the night in question, it was taking passengers from Leyte Island to the capital city of Manila. The ferry had departed at 6:30 that morning, and it was scheduled to dock in Manila at 4 am the next day.\n\nFor most of the trip, it had been smooth sailing, relatively speaking. The seas were a bit choppy, but it was a clear night with no signs of storms. Things were so uneventful that the entire crew of the Doña Paz decided they may as well spend the evening having a party. They all gathered in the crew's recreation quarters to get drunk and watch a movie on the captain's Betamax player. They had left only a single apprentice on the ship's bridge to monitor everything, essentially leaving an intern in charge of the entire ship.\n\nBy 10:30 that night, most of the passengers were asleep and most of the crew was drunk. We'll never know whether or not the lone apprentice left on duty spotted the MT Vector before their collision. Normally you might expect that a nearby ship would have heard radio communications between the two ships and been able to corroborate when they started talking and when they collided, but this couldn't happen because the Doña Paz didn't have a radio.\n\nAs for the Vector, it was an oil tanker with a crew of 13 people and a cargo of gasoline and other petroleum products totaling 1.05 million liters, or 8,800 US barrels. The Vector was also operating without a license, a lookout, or a qualified captain. Given what a shit show both crews were it would be hard for us to say who was at fault, but according to the Supreme Court of the Philippines, the company that owned the oil tanker was at fault.\n\nAnyway, at about 10:30 the ships collided, and the oil tanker's cargo immediately caught fire. Not only did the fire spread to the Doña Paz, the flaming gasoline spread along the surface of the water surrounding both ships.\n\nUnfortunately, the crew of the Doña Paz was not prepared for…well, for much of anything, really. Rather than trying to create some semblance of order among the panicked guests and execute evacuation protocols, they joined in the panicking. The lifejackets were all locked up, and either nobody had a key or nobody with a key had the wherewithal to take action and distribute them. There were technically a few lifeboats, but the fire had spread too quickly for them to be boarded and deployed into the water that was also on fire. Basically, everybody on board was left to fend for themselves, which did not end well.\n\nWithin two hours of the collision, the Doña Paz had completely sunk. The Vector followed suit two hours later. The nearby ship, MV Don Claudio, saw the explosion happen and immediately set course to provide aid. Within an hour they arrived on the scene and cast out a net to rescue the survivors of both ships. Two of the 13 crew members of the Vector survived, with only 24 survivors from the Doña Paz (none of them members of the crew). Lots of people were traveling because of Christmas, so the passengers and crew were originally believed to total 1,518, the ship's maximum capacity.\n\nHowever, there was the ship's official capacity, and then there was the reality of the situation. Of the 24 survivors from the Doña Paz, only five were listed on the ship's manifest. When search teams began recovering and identifying the charred bodies from the water, only one out of the 21 bodies initially found were on the manifest. As it turned out, the ship had been massively overbooked.\n\nTo start, anyone who received a free ticket for the ferry and children under the age of four were not added to the manifest. By not listing people who were riding for free, it allowed them to sell the full complement of tickets to fill out the manifest. And once the manifest was filled, it was the company's unwritten policy to illegally sell additional tickets at a discounted rate. This was first reported by an anonymous source within the company, but it was corroborated by the testimony of survivors who saw beds with 3-4 people crammed in each and who saw people sleeping on the floor of rooms and on the ship's decks.\n\nWithin months it was identified that there were over 3,000 people aboard the Doña Paz, and after more than a decade of research, the official death toll was declared as being 4,385 people, nearly triple the maximum capacity for the ship.\n\n## Bhopal Disaster\n\nIt's an unfortunate reality of life that dangerous products need to be produced somewhere. For Union Carbide India Limited, manufacturer of the pesticide Sevin, that somewhere was a factory in the industrial district of Bhopal, less than one kilometer away from densely populated parts of the city. So when things went wrong on December 3, 1984, it became the worst industrial accident in history.\n\nIn order to produce the pesticide, the plant manufactured methyl isocyanate (MIC). At room temperature, MIC is a colourless, flammable liquid. Its boiling point is around 40 degrees C (100 degrees F), but it is extremely volatile so it can still release vapor at lower temperatures, especially if it comes into contact with water. Oh, and it is also extremely toxic to humans with no known antidote. All you can do is treat the symptoms and hope for the best.\n\nAnyway, despite dealing with dangerous chemicals, the factory in Bhopal had a disturbing history of leaks and accidents. These were small incidents that only affected workers at the factory, but there were four leaks in 1982 and several more across 1983 and 1984. With the frequency of these leaks you might think they would repair the factory before something bad happened, but you would be wrong.\n\nThere were three massive tanks at the facility used to store liquid MIC. Company safety regulations mandated that none of the tanks could be filled above 50% capacity, and the rest of the tank was filled with inert nitrogen gas to pressurize the tank so that the liquid MIC could be pumped out. Having the remaining volume of the tank completely taken up by nitrogen also prevented contaminants, particularly water, from getting into the tank.\n\nIn October of 1984 one of the tanks began leaking its nitrogen, so MIC production was shut down. A couple weeks later they resumed production of pesticides using the MIC already contained in the other two tanks, but the 42 tons of liquid MIC remained trapped in the third tank.\n\nOn December 1st they attempted to pressurize the tank again to flush the MIC out, but to no avail. The following evening, late at night, it is believed that water from a routine pipe cleaning got into the tank thanks to missing or broken safety plates. The introduction of water to the MIC, combined with contaminants that had started to build up in the absence of nitrogen, caused a runaway reaction that made the tank heat up and build in pressure.\n\nAt 10:30 pm that evening, the tank was at an extremely safe 2 psi. By 11 pm, it was up to 10 psi. Two employees reading the instruments saw the change, but assumed that the pressure gage was just malfunctioning. After all, everything else at the factory was broken, so it made sense for the gage to be as well. It wasn't until 11:30 pm that workers began to feel the effects of the MIC gas leaking from the tank, at which point they took the measurement more seriously.\n\nAbout 15 minutes later they found a leak and reported it to the supervisor. India was no longer under British rule at this point, but apparently old habits die hard, because the supervisor said to just look for any other leaks and that they'd attempt to fix the problem after their 12:15 am tea break.\n\nBy the time tea was finished at 12:40, the reaction in the tank had reached a critical state. The temperature in the tank was literally off the scale, as the gage only went up to 25 degrees C (77 degrees F). Anything above 11 degrees should have caused an alarm to go off, but the refrigeration system had broken for two years earlier, so they just disabled the alarm instead of fixing the refrigeration. The pressure was also up to 40 psi at that point, with large amounts of gas leaking into the atmosphere.\n\nBut the refrigeration system was just one of three safety measures put into place to prevent toxic gas from leaking out of the plant. There was also a flare tower that was designed to burn any gas that would escape from the plant. This tower was also broken, and it had been shut down for repairs a couple months earlier when production of MCI halted.\n\nThere were also vent gas scrubbers, devices intended to remove pollutants from the air by absorbing them into some other substance, in this case sodium hydroxide (also known as caustic soda). But the scrubbers were also either broken or disabled, and they didn't have nearly enough caustic soda to absorb the amount of gas that was leaking anyway.\n\nAt 12:50 am the alarm was sounded inside the plant, but they chose not to activate the alarm to warn the population of Bhopal, wanting to prevent a panic. This was how alarms at the factory had been handled for years, but the previous incidents were only endangering employees within the plant. In this instance, the people of Bhopal would have benefited from a healthy dose of panic.\n\nAs employees fled the factory and headed upwind, a massive cloud of toxic gas began heading southeast of the plant towards heavily populated areas. It wasn't until about 2:15 am that a siren was finally sounded in Bhopal and the police were informed of the leak.\n\nBut it was already too late at that point. While some people may have found out about the gas leak from the alarm, most of those affected found out after either breathing in the gas or seeing the toxic cloud heading towards their homes. Because the toxic gases (which included things like chloroform and carbon dioxide in addition to MCI) were heavier than air, the cloud stayed close to the ground, effecting children and short people more severely.\n\nBy the time the sun rose in Bhopal that morning, over half a million people had been exposed to the extremely toxic MIC gas. While most injuries were minor, about 3,900 people suffered severe or permanent injuries from the toxic gas, and another 3,787 people died as a result of acute exposure. That's the official number from the government, but it's believed that another 8,000 people died over the course of the next two weeks because of their exposure to the gas, with another 8,000 dying from complications of it in the time since.\n\n## Banqiao Dam Failure\n\nIn the 1950s, China built three major dams along the Huai River: Banqiao, Shimantan, and Baisha. The goal of these dams was threefold: to prevent flooding, store and reroute water for irrigation, and generate electricity. There had been some severely flooding of the Huai River Basin in 1949 and 1950, so the dams were intended to prevent that from happening again as well as providing other benefits while they were at it. The only problem was that China had no idea how to build dams at this scale, so they got the Soviet Union to send them some experts to help design the dams.\n\nThere were some oversights with the design though. To start, safety wasn't a high priority. Even though preventing flooding was one of the three stated goals of the dams (and was the reason the project was started in the first place) it wasn't seen as terribly important. Generating electricity and storing water for irrigation provided real, tangible benefits, but investing a bunch of money in safety seemed like a bit of a waste. It would drive up construction costs without added benefits, so flood control was heavily deprioritized. Still, the dam was claimed to be able to support a \"one in a thousand year\" rainfall event of a foot of rain in a single day.\n\nShortly after the completion of these dams, Mao Zedong launched his Great Leap Forward, a campaign intended to rapidly industrialize China. This saw the construction of over 100 more dams along the Huai River, though the massive industrialization efforts also severely damaged the ecosystem.\n\nFor a little while everything worked okay, but the dams had been poorly designed with minimal margins for safety, used substandard materials, and were not properly maintained. The damaged ecosystem also suffered from land degradation and had far less forest cover, factors which made the area much more susceptible to flooding than it previously had been.\n\nAs we said, the Banqiao Dam was theoretically designed to withstand a foot of rain in a single day. But when Typhoon Nina made landfall on August 6, 1975, it didn't drop a foot of rain in a day, it dropped nearly a meter of rain, most of which was over the course of just six hours.\n\nDam operators requested permission to open the dam and let out some of the water, but the request was denied because there was some flooding downstream. A day later the request was accepted, but the telegram never reached anyone at Banqiao Dam. Since the dam wasn't designed to handle this level of rainfall, at 1 am on August 8 the dam failed, sending 700 million cubic meters of water rushing out over six hours.\n\nWaves 10 km (6 miles) long and 7 meters (23 feet) tall sped towards Suiping County at 50 kph (31 mph). The military was stationed at the dam, but telegraph lines went down and their flares were misunderstood, so they were unable to warn anybody effectively. Once communities started being destroyed and the catastrophe that had been unleashed by the damn was understood, steps were taken to try to minimize the damage.\n\nFlood diversion areas were ordered to be evacuated while the Chinese military dispatched planes to launch air strikes against the remaining dams in an attempt to force the water out of the dam in a specific direction to minimize flooding. Despite these efforts, the Shimantan Dam also failed on August 8. Throughout the following day dams continued to collapse, with air strikes being used to try to redirect water as best as possible.\n\nAlthough this cascade of events was triggered by a natural disaster, Typhoon Nina had already weakened to a tropical storm before hitting China. The area around Banqiao Dam did get the worst of what remained of the storm, but the devastation caused by the dam's failure is still considered a manmade disaster thanks to the poorly designed and maintained dams, as well as the damage to the ecosystem from industrialization creating perfect conditions for flooding. And when we say devastation, we definitely mean it.\n\nIn total 62 dams collapsed, which doesn't include the dams that were intentionally destroyed with air strikes. More than 5 million buildings were destroyed with nearly 11 million people affected. Entire towns were destroyed, especially in Suiping County. Daowencheng Commune, with a population of 9,600 people, was washed off the map entirely. Every building was destroyed, and every person died.\n\nSince this story took place in Communist China, it's difficult to get exact numbers on how many people died as a result of the Banqiao Dam failure. There was a major government cover up with no official documents mentioning the events until 1995, two full decades later, and it wasn't until 2005 that documents related to the disaster were finally declassified.\n\nAccording to the official report from the Chinese government, the official death total is 26,000 people. However, unofficial sources claim that 85,600 people died during the disaster, and that when including deaths from famine, infection, and epidemics caused directly by the flooding, the death toll reaches 240,000.\n\nThat all said, while this is widely considered a manmade disaster, the Chinese government disagrees. They contend that they did nothing wrong, and that the Banqiao Dam was properly built to withstand a one in a thousand year rainfall. According to the CCP, the problem was that Typhoon Nina was a one in two thousand year rainfall.\n\n## Key Takeaways\n\n- The Porto Boat Bridge disaster in 1809 resulted in around 4,000 deaths due to a collapsing bridge during a war.\n- The MV Doña Paz ferry disaster in 1987 was the deadliest peacetime maritime disaster, with over 4,385 deaths due to overbooking and crew negligence.\n- The Bhopal disaster in 1984 was the worst industrial accident in history, killing thousands due to a toxic gas leak from a pesticide plant.\n- The Banqiao Dam failure in 1975 caused widespread flooding and devastation, with deaths estimated between 26,000 and 240,000 due to poor dam design and maintenance.\n- Many deadly manmade disasters, such as the Porto Bridge collapse and Bhopal gas leak, were preventable with proper safety measures and maintenance.\n\n## Frequently Asked Questions\n\n### What was the cause of the Porto Boat Bridge Disaster?\n\nThe Porto Boat Bridge Disaster was caused by the collapse of a pontoon bridge during the First Battle of Porto in 1809. The bridge collapsed due to a combination of factors including the weight of thousands of people fleeing the city, possible sabotage by Portuguese soldiers, and the bridge's design allowing it to open for boat passage.\n\n### How many people died in the Porto Boat Bridge Disaster?\n\nEstimates put the total number of lives lost at around 4,000, making it the deadliest bridge disaster in history.\n\n### What was the cause of the MV Doña Paz ferry disaster?\n\nThe MV Doña Paz ferry disaster was caused by a collision with the oil tanker MT Vector. The collision resulted in a fire that spread to the ferry, leading to its sinking within two hours.\n\n### How many people were on board the MV Doña Paz when it sank?\n\nWithin months it was identified that there were over 3,000 people aboard the MV Doña Paz, and after more than a decade of research, the official death toll was declared as being 4,385 people.\n\n### What caused the Bhopal Disaster?\n\nThe Bhopal Disaster was caused by the release of methyl isocyanate (MIC) gas from a Union Carbide India Limited pesticide plant. The gas leak occurred due to a combination of factors including water entering the MIC storage tank, lack of maintenance, and disabled safety systems.\n\n### How many people were affected by the Bhopal Disaster?\n\nBy the time the sun rose in Bhopal that morning, over half a million people had been exposed to the extremely toxic MIC gas. While most injuries were minor, about 3,900 people suffered severe or permanent injuries from the toxic gas, and another 3,787 people died as a result of acute exposure.\n\n### What triggered the Banqiao Dam failure?\n\nThe Banqiao Dam failure was triggered by Typhoon Nina, which dropped nearly a meter of rain in six hours. The dam was not designed to handle such extreme rainfall and failed, leading to a cascade of dam failures along the Huai River.\n\n### How many people were affected by the Banqiao Dam failure?\n\nMore than 5 million buildings were destroyed with nearly 11 million people affected. Entire towns were destroyed, especially in Suiping County.\n\n### What was the official death toll from the Banqiao Dam failure?\n\nAccording to the official report from the Chinese government, the official death total is 26,000 people. However, unofficial sources claim that 85,600 people died during the disaster, and that when including deaths from famine, infection, and epidemics caused directly by the flooding, the death toll reaches 240,000.\n\n### What were the goals of the Banqiao Dam?\n\nThe goal of these dams was threefold: to prevent flooding, store and reroute water for irrigation, and generate electricity.\n\n## Sources\n\n- [Original Side Projects video: History's Deadliest Manmade Disasters...](https://www.youtube.com/watch?v=IMn2EhVkYs8)\n\n## Related Coverage" url: https://sideprojects.pub/article/history-deadliest-manmade-disasters.md canonical: https://sideprojects.pub/article/history-deadliest-manmade-disasters datePublished: 2026-06-25 dateModified: 2026-06-25 author: - name: Simon Whistler url: https://sideprojects.pub/author/simon-whistler publisher: Side Projects image: "https://media.sideprojects.pub/cdn-cgi/image/width=1600,height=900,fit=cover,quality=80,format=auto/articles/IMn2EhVkYs8/hero.jpg" type: NewsArticle contentHash: 0cde1e9b39af846c5eb0a3834e16ba51a9ab4c34003c5cdb995d6033708b6ea0 tokens: 6083 summaryUrl: https://sideprojects.pub/article/history-deadliest-manmade-disasters.md.summary.md --- When we think about deadly disasters, the first things that come to mind tend to be things like earthquakes, volcanoes, and hurricanes. But there are some types of disasters that could only be caused by humans. And whether it's failing dams wiping out millions of homes in a single day or clouds of poisonous gas descending upon heavily populated cities, the deadliest manmade disasters have always been completely preventable. ## Porto Boat Bridge Disaster If you ever visit Porto, the second largest city in Portugal, you can take an hour long boat ride called The Six Bridges Cruise. As you might guess from the name, this cruise offers a beautiful view of Porto's six bridges that cross the Douro River, as well as providing history about the bridges. However, that history does not go back nearly as far as you might assume, as there was no bridge across the river until the early 1800s. Before then, people primarily relied on boats and rafts to cross the river. If special circumstances, like a festival, were going to require a great deal of travel across the river in a short period of time, then a temporary pontoon bridge would be constructed for the event, but these instances were rare and short lived. It wasn't until 1806 that the first permanent pontoon bridge was built across the river to connect Porto and Vila Nova de Gaia. Unfortunately for the Portuguese, the following year Napoleon decided that they should be part of France now. The French were able to invade and occupy Portugal with the aid of Spain, but then Napoleon pissed off the Spanish, resulting in the Peninsular War with France fighting against the coalition of Portugal, Spain, and the United Kingdom. Napoleon's forces were driven out of Portugal in 1808, but in early 1809 he decided he wanted to have another go at it. The First Battle of Porto took place on March 28, 1809. Although the French were outnumbered, the Portuguese were outgunned, inexperienced, and disorganized. This led to a French victory in Porto, with the Portuguese soldiers fleeing across the bridge towards Gaia. But it wasn't just soldiers trying to flee, as Marshal General Jean-de-Dieu Soult had given the French troops permission to pillage the city of Porto for the next three days. This caused people to flee the city by the thousands, taking what they could and fleeing towards Gaia. The reason for what happened next isn't entirely clear, with there being three different explanations for what caused the disaster. Any or all of the following could have happened: Portuguese soldiers fleeing the French may have sabotaged parts of the bridge, after crossing the bridge the soldiers may have opened the middle of the bridge (as it was designed to open and allow boats to pass through), or the bridge may have collapsed from the sheer weight of the thousands of people trying to cross. Though we can't say for sure which or how many of those three things happened, we know that thousands of people fell from the bridge to their deaths. Large sections of the bridge were destroyed and needed to be repaired following the disaster, though it's hard to know whether it was only from the weight of all of the people fleeing at once or if the bridge had been sabotaged (especially since the bridge was fully dismantled in 1843, so it can't be analyzed with newer technology). Worse still, some of the civilians who fell off that bridge were already dead before they fell. The French had been pursuing the Portuguese across the bridge, and the two armed forces continued to fire upon one another even though their shots were obstructed by the thousands of fleeing civilians. Some soldiers were wounded or killed in these volleys, but it was mostly just civilians being killed by both armies. Portuguese cavalry had also killed civilians with their swords in an attempt to clear a path for their horses, horses who also trampled fallen civilians to death. While we didn't want to include acts of war while discussing manmade disasters, the vast majority of civilian deaths in this disaster were the result of the collapsing bridge rather than being killed by soldiers, even if war was the direct cause of the bridge being overloaded with civilians. Though exact numbers aren't known, all estimates put the total number of lives lost at around 4,000, making this the deadliest bridge disaster in history. ## MV Doña Paz Ferry Disaster The sinking of the RMS Titanic is, by far, the most famous maritime disaster to ever occur during peacetime. At the time it was also the deadliest, with just over 1,500 dead, but it has since fallen into a very distant third thanks to events that unfolded on December 20, 1987, in the Philippines. The MV Doña Paz was a ferry with a maximum capacity of 1,518 passengers. On the night in question, it was taking passengers from Leyte Island to the capital city of Manila. The ferry had departed at 6:30 that morning, and it was scheduled to dock in Manila at 4 am the next day. For most of the trip, it had been smooth sailing, relatively speaking. The seas were a bit choppy, but it was a clear night with no signs of storms. Things were so uneventful that the entire crew of the Doña Paz decided they may as well spend the evening having a party. They all gathered in the crew's recreation quarters to get drunk and watch a movie on the captain's Betamax player. They had left only a single apprentice on the ship's bridge to monitor everything, essentially leaving an intern in charge of the entire ship. By 10:30 that night, most of the passengers were asleep and most of the crew was drunk. We'll never know whether or not the lone apprentice left on duty spotted the MT Vector before their collision. Normally you might expect that a nearby ship would have heard radio communications between the two ships and been able to corroborate when they started talking and when they collided, but this couldn't happen because the Doña Paz didn't have a radio. As for the Vector, it was an oil tanker with a crew of 13 people and a cargo of gasoline and other petroleum products totaling 1.05 million liters, or 8,800 US barrels. The Vector was also operating without a license, a lookout, or a qualified captain. Given what a shit show both crews were it would be hard for us to say who was at fault, but according to the Supreme Court of the Philippines, the company that owned the oil tanker was at fault. Anyway, at about 10:30 the ships collided, and the oil tanker's cargo immediately caught fire. Not only did the fire spread to the Doña Paz, the flaming gasoline spread along the surface of the water surrounding both ships. Unfortunately, the crew of the Doña Paz was not prepared for…well, for much of anything, really. Rather than trying to create some semblance of order among the panicked guests and execute evacuation protocols, they joined in the panicking. The lifejackets were all locked up, and either nobody had a key or nobody with a key had the wherewithal to take action and distribute them. There were technically a few lifeboats, but the fire had spread too quickly for them to be boarded and deployed into the water that was also on fire. Basically, everybody on board was left to fend for themselves, which did not end well. Within two hours of the collision, the Doña Paz had completely sunk. The Vector followed suit two hours later. The nearby ship, MV Don Claudio, saw the explosion happen and immediately set course to provide aid. Within an hour they arrived on the scene and cast out a net to rescue the survivors of both ships. Two of the 13 crew members of the Vector survived, with only 24 survivors from the Doña Paz (none of them members of the crew). Lots of people were traveling because of Christmas, so the passengers and crew were originally believed to total 1,518, the ship's maximum capacity. However, there was the ship's official capacity, and then there was the reality of the situation. Of the 24 survivors from the Doña Paz, only five were listed on the ship's manifest. When search teams began recovering and identifying the charred bodies from the water, only one out of the 21 bodies initially found were on the manifest. As it turned out, the ship had been massively overbooked. To start, anyone who received a free ticket for the ferry and children under the age of four were not added to the manifest. By not listing people who were riding for free, it allowed them to sell the full complement of tickets to fill out the manifest. And once the manifest was filled, it was the company's unwritten policy to illegally sell additional tickets at a discounted rate. This was first reported by an anonymous source within the company, but it was corroborated by the testimony of survivors who saw beds with 3-4 people crammed in each and who saw people sleeping on the floor of rooms and on the ship's decks. Within months it was identified that there were over 3,000 people aboard the Doña Paz, and after more than a decade of research, the official death toll was declared as being 4,385 people, nearly triple the maximum capacity for the ship. ## Bhopal Disaster It's an unfortunate reality of life that dangerous products need to be produced somewhere. For Union Carbide India Limited, manufacturer of the pesticide Sevin, that somewhere was a factory in the industrial district of Bhopal, less than one kilometer away from densely populated parts of the city. So when things went wrong on December 3, 1984, it became the worst industrial accident in history. In order to produce the pesticide, the plant manufactured methyl isocyanate (MIC). At room temperature, MIC is a colourless, flammable liquid. Its boiling point is around 40 degrees C (100 degrees F), but it is extremely volatile so it can still release vapor at lower temperatures, especially if it comes into contact with water. Oh, and it is also extremely toxic to humans with no known antidote. All you can do is treat the symptoms and hope for the best. Anyway, despite dealing with dangerous chemicals, the factory in Bhopal had a disturbing history of leaks and accidents. These were small incidents that only affected workers at the factory, but there were four leaks in 1982 and several more across 1983 and 1984. With the frequency of these leaks you might think they would repair the factory before something bad happened, but you would be wrong. There were three massive tanks at the facility used to store liquid MIC. Company safety regulations mandated that none of the tanks could be filled above 50% capacity, and the rest of the tank was filled with inert nitrogen gas to pressurize the tank so that the liquid MIC could be pumped out. Having the remaining volume of the tank completely taken up by nitrogen also prevented contaminants, particularly water, from getting into the tank. In October of 1984 one of the tanks began leaking its nitrogen, so MIC production was shut down. A couple weeks later they resumed production of pesticides using the MIC already contained in the other two tanks, but the 42 tons of liquid MIC remained trapped in the third tank. On December 1st they attempted to pressurize the tank again to flush the MIC out, but to no avail. The following evening, late at night, it is believed that water from a routine pipe cleaning got into the tank thanks to missing or broken safety plates. The introduction of water to the MIC, combined with contaminants that had started to build up in the absence of nitrogen, caused a runaway reaction that made the tank heat up and build in pressure. At 10:30 pm that evening, the tank was at an extremely safe 2 psi. By 11 pm, it was up to 10 psi. Two employees reading the instruments saw the change, but assumed that the pressure gage was just malfunctioning. After all, everything else at the factory was broken, so it made sense for the gage to be as well. It wasn't until 11:30 pm that workers began to feel the effects of the MIC gas leaking from the tank, at which point they took the measurement more seriously. About 15 minutes later they found a leak and reported it to the supervisor. India was no longer under British rule at this point, but apparently old habits die hard, because the supervisor said to just look for any other leaks and that they'd attempt to fix the problem after their 12:15 am tea break. By the time tea was finished at 12:40, the reaction in the tank had reached a critical state. The temperature in the tank was literally off the scale, as the gage only went up to 25 degrees C (77 degrees F). Anything above 11 degrees should have caused an alarm to go off, but the refrigeration system had broken for two years earlier, so they just disabled the alarm instead of fixing the refrigeration. The pressure was also up to 40 psi at that point, with large amounts of gas leaking into the atmosphere. But the refrigeration system was just one of three safety measures put into place to prevent toxic gas from leaking out of the plant. There was also a flare tower that was designed to burn any gas that would escape from the plant. This tower was also broken, and it had been shut down for repairs a couple months earlier when production of MCI halted. There were also vent gas scrubbers, devices intended to remove pollutants from the air by absorbing them into some other substance, in this case sodium hydroxide (also known as caustic soda). But the scrubbers were also either broken or disabled, and they didn't have nearly enough caustic soda to absorb the amount of gas that was leaking anyway. At 12:50 am the alarm was sounded inside the plant, but they chose not to activate the alarm to warn the population of Bhopal, wanting to prevent a panic. This was how alarms at the factory had been handled for years, but the previous incidents were only endangering employees within the plant. In this instance, the people of Bhopal would have benefited from a healthy dose of panic. As employees fled the factory and headed upwind, a massive cloud of toxic gas began heading southeast of the plant towards heavily populated areas. It wasn't until about 2:15 am that a siren was finally sounded in Bhopal and the police were informed of the leak. But it was already too late at that point. While some people may have found out about the gas leak from the alarm, most of those affected found out after either breathing in the gas or seeing the toxic cloud heading towards their homes. Because the toxic gases (which included things like chloroform and carbon dioxide in addition to MCI) were heavier than air, the cloud stayed close to the ground, effecting children and short people more severely. By the time the sun rose in Bhopal that morning, over half a million people had been exposed to the extremely toxic MIC gas. While most injuries were minor, about 3,900 people suffered severe or permanent injuries from the toxic gas, and another 3,787 people died as a result of acute exposure. That's the official number from the government, but it's believed that another 8,000 people died over the course of the next two weeks because of their exposure to the gas, with another 8,000 dying from complications of it in the time since. ## Banqiao Dam Failure In the 1950s, China built three major dams along the Huai River: Banqiao, Shimantan, and Baisha. The goal of these dams was threefold: to prevent flooding, store and reroute water for irrigation, and generate electricity. There had been some severely flooding of the Huai River Basin in 1949 and 1950, so the dams were intended to prevent that from happening again as well as providing other benefits while they were at it. The only problem was that China had no idea how to build dams at this scale, so they got the Soviet Union to send them some experts to help design the dams. There were some oversights with the design though. To start, safety wasn't a high priority. Even though preventing flooding was one of the three stated goals of the dams (and was the reason the project was started in the first place) it wasn't seen as terribly important. Generating electricity and storing water for irrigation provided real, tangible benefits, but investing a bunch of money in safety seemed like a bit of a waste. It would drive up construction costs without added benefits, so flood control was heavily deprioritized. Still, the dam was claimed to be able to support a "one in a thousand year" rainfall event of a foot of rain in a single day. Shortly after the completion of these dams, Mao Zedong launched his Great Leap Forward, a campaign intended to rapidly industrialize China. This saw the construction of over 100 more dams along the Huai River, though the massive industrialization efforts also severely damaged the ecosystem. For a little while everything worked okay, but the dams had been poorly designed with minimal margins for safety, used substandard materials, and were not properly maintained. The damaged ecosystem also suffered from land degradation and had far less forest cover, factors which made the area much more susceptible to flooding than it previously had been. As we said, the Banqiao Dam was theoretically designed to withstand a foot of rain in a single day. But when Typhoon Nina made landfall on August 6, 1975, it didn't drop a foot of rain in a day, it dropped nearly a meter of rain, most of which was over the course of just six hours. Dam operators requested permission to open the dam and let out some of the water, but the request was denied because there was some flooding downstream. A day later the request was accepted, but the telegram never reached anyone at Banqiao Dam. Since the dam wasn't designed to handle this level of rainfall, at 1 am on August 8 the dam failed, sending 700 million cubic meters of water rushing out over six hours. Waves 10 km (6 miles) long and 7 meters (23 feet) tall sped towards Suiping County at 50 kph (31 mph). The military was stationed at the dam, but telegraph lines went down and their flares were misunderstood, so they were unable to warn anybody effectively. Once communities started being destroyed and the catastrophe that had been unleashed by the damn was understood, steps were taken to try to minimize the damage. Flood diversion areas were ordered to be evacuated while the Chinese military dispatched planes to launch air strikes against the remaining dams in an attempt to force the water out of the dam in a specific direction to minimize flooding. Despite these efforts, the Shimantan Dam also failed on August 8. Throughout the following day dams continued to collapse, with air strikes being used to try to redirect water as best as possible. Although this cascade of events was triggered by a natural disaster, Typhoon Nina had already weakened to a tropical storm before hitting China. The area around Banqiao Dam did get the worst of what remained of the storm, but the devastation caused by the dam's failure is still considered a manmade disaster thanks to the poorly designed and maintained dams, as well as the damage to the ecosystem from industrialization creating perfect conditions for flooding. And when we say devastation, we definitely mean it. In total 62 dams collapsed, which doesn't include the dams that were intentionally destroyed with air strikes. More than 5 million buildings were destroyed with nearly 11 million people affected. Entire towns were destroyed, especially in Suiping County. Daowencheng Commune, with a population of 9,600 people, was washed off the map entirely. Every building was destroyed, and every person died. Since this story took place in Communist China, it's difficult to get exact numbers on how many people died as a result of the Banqiao Dam failure. There was a major government cover up with no official documents mentioning the events until 1995, two full decades later, and it wasn't until 2005 that documents related to the disaster were finally declassified. According to the official report from the Chinese government, the official death total is 26,000 people. However, unofficial sources claim that 85,600 people died during the disaster, and that when including deaths from famine, infection, and epidemics caused directly by the flooding, the death toll reaches 240,000. That all said, while this is widely considered a manmade disaster, the Chinese government disagrees. They contend that they did nothing wrong, and that the Banqiao Dam was properly built to withstand a one in a thousand year rainfall. According to the CCP, the problem was that Typhoon Nina was a one in two thousand year rainfall. ## Key Takeaways - The Porto Boat Bridge disaster in 1809 resulted in around 4,000 deaths due to a collapsing bridge during a war. - The MV Doña Paz ferry disaster in 1987 was the deadliest peacetime maritime disaster, with over 4,385 deaths due to overbooking and crew negligence. - The Bhopal disaster in 1984 was the worst industrial accident in history, killing thousands due to a toxic gas leak from a pesticide plant. - The Banqiao Dam failure in 1975 caused widespread flooding and devastation, with deaths estimated between 26,000 and 240,000 due to poor dam design and maintenance. - Many deadly manmade disasters, such as the Porto Bridge collapse and Bhopal gas leak, were preventable with proper safety measures and maintenance. ## Frequently Asked Questions ### What was the cause of the Porto Boat Bridge Disaster? The Porto Boat Bridge Disaster was caused by the collapse of a pontoon bridge during the First Battle of Porto in 1809. The bridge collapsed due to a combination of factors including the weight of thousands of people fleeing the city, possible sabotage by Portuguese soldiers, and the bridge's design allowing it to open for boat passage. ### How many people died in the Porto Boat Bridge Disaster? Estimates put the total number of lives lost at around 4,000, making it the deadliest bridge disaster in history. ### What was the cause of the MV Doña Paz ferry disaster? The MV Doña Paz ferry disaster was caused by a collision with the oil tanker MT Vector. The collision resulted in a fire that spread to the ferry, leading to its sinking within two hours. ### How many people were on board the MV Doña Paz when it sank? Within months it was identified that there were over 3,000 people aboard the MV Doña Paz, and after more than a decade of research, the official death toll was declared as being 4,385 people. ### What caused the Bhopal Disaster? The Bhopal Disaster was caused by the release of methyl isocyanate (MIC) gas from a Union Carbide India Limited pesticide plant. The gas leak occurred due to a combination of factors including water entering the MIC storage tank, lack of maintenance, and disabled safety systems. ### How many people were affected by the Bhopal Disaster? By the time the sun rose in Bhopal that morning, over half a million people had been exposed to the extremely toxic MIC gas. While most injuries were minor, about 3,900 people suffered severe or permanent injuries from the toxic gas, and another 3,787 people died as a result of acute exposure. ### What triggered the Banqiao Dam failure? The Banqiao Dam failure was triggered by Typhoon Nina, which dropped nearly a meter of rain in six hours. The dam was not designed to handle such extreme rainfall and failed, leading to a cascade of dam failures along the Huai River. ### How many people were affected by the Banqiao Dam failure? More than 5 million buildings were destroyed with nearly 11 million people affected. Entire towns were destroyed, especially in Suiping County. ### What was the official death toll from the Banqiao Dam failure? According to the official report from the Chinese government, the official death total is 26,000 people. However, unofficial sources claim that 85,600 people died during the disaster, and that when including deaths from famine, infection, and epidemics caused directly by the flooding, the death toll reaches 240,000. ### What were the goals of the Banqiao Dam? The goal of these dams was threefold: to prevent flooding, store and reroute water for irrigation, and generate electricity. ## Sources - [Original Side Projects video: History's Deadliest Manmade Disasters...](https://www.youtube.com/watch?v=IMn2EhVkYs8) ## Related Coverage