gh the bad. Mulholland proposed an ambitious plan to increase the reservoir capacity around the city, near his aqueduct's terminus. The project would involve modifying existing waterworks and constructing seven entirely new dams, the largest of which would be the St Francis. The new dam would store 30,000 acre feet of water, roughly the amount consumed by city residents in 1922. Surveys for the location for the new dam began in 1922, eventually the site was settled upon and initial clearingworks began. Strangely, but understandably, the initial building works went on with little fanfare, but this was because Mulholland had been burnt before. During the aqueduct construction, sabotage cost the project money as disgruntled locals and landowners sought to cause trouble. By July 1st 1924 preliminary clearingworks had been completed and main construction works would begin around six weeks later. But first we need to look at the design of this shiny new to be built dam. The basic design was actually copied from the Mulholland dam built a year before by, you guessed it, Mulholland, designed by Edgar A. Bailey. This would be the second dam constructed of concrete by the Los Angeles Department of Water and Power. Chief Engineer, W. W. Holbert, supervised the transfer of the design from the Mulholland location to the St Francis location. The main changes were adjustments to fit the new setting or the St Francis area. As such, Bill Mulholland didn't manage the project on the micro level like he had on other designs before. This was exasperated by him being distracted by the concept of a Colorado river aqueduct. Before the designs of both dams, the engineering team studied a number of recent concrete dams such as the Arrow Rock Dam in Idaho and the Elephant Butte Dam in New Mexico. A storage capacity of 32,000 acre feet and an elevation of 1825 feet above sea level was envisioned in 1924 after initial survey work. The Heitler Dam was increased by 10 feet to allow a water capacity of 38,000 acre feet in 1925. The increased size necessitated the construction of a 588 foot long dike along the top of the ridge next to the western abutment. This was not in the original design. As such, the foundations were not widened for the extra height. The design incorporated a curved plan laid out on a radius of 500 feet with a distinctive series of 5 foot high vertical steps on a downstream face of the main dam. Each step was unique in its width and was a simple solution to building a complex curve. The dam didn't have a provision for groutable contraction joints however. A concrete batch plant was built in the canyon of the dam and local aggregate was incorporated with around one barrel of Portland cement per cubic yard of concrete. When the concrete was poured, little thought was given to contractions due to heat given off whilst curing. This combined with the oversight for contraction joints left the dam inflexible and potentially unstable. The reservoir that the dam would hold back began being filled in March 1926. With water diverted from the Owens River Aqueduct and the completed dam was opened in May 1926. During reservoir filling a number of small cracks and leaks were detected but thought to be within expected tolerances. Between March and June the reservoir filled at a rate of about 1.8 feet per day and on May 10th 1927 the reservoir pool reached an elevation of 1832 feet just three feet below the spillway crest. Summer demand kept the water level at that elevation. During the winter months between 1927 and 1928 the reservoir was allowed to fill up to just three inches below the spillway. By around February all of LA's reservoirs were beginning to fill up and on the 7th of March Aqueduct water was no longer diverted to the reservoir. Damkeeper Tony Harnish-Feger alerted the company on the morning of the 12th to dirty water cascading down the slope below the dam's right abutment. The presence of dirty water can give an indication of foundation erosion. Because the reservoir was at maximum fill and new cracks in the concrete were discovered over the previous week Mulholland and Harvey Van Norman arrived to investigate the dirty water and the dam as a whole. Arriving at 11am the two men began to investigate the instability of the structure. The cause of the dirty water was seen to be clear water mixing with loose dirt from a newly constructed road although alarming it was seen as a problem that could be rectified later on. The rest of the structure was inspected and given the seal of approval well how wrong they would be just 12 hours later. Around 8pm employees from one of the nearby powerhouses witnessed a 12 inch wide crack on a nearby road upstream from the dam hinting towards the land around the dam beginning to shift. Ace Hopewell powerhouse number one's carpenter was riding his motorcycle along the road nearby passing the crest of the dam around 11.50pm. He pulled up his bike and sidecar around a mile up from the dam to have a cigarette and to investigate a loud crashing sound. The Southern California Edison company experienced a loss of power at 11.57pm on near 70 kilovolt borough power line that ran near the dam's left abutment extending east woods to Palmdale. The shorting out the power line hints at large scale landslide that enveloped the dam's entire left abutment starting off the disaster. In the closing minutes of the 12th and the opening of the 13th of March 1928 the dam experienced a catastrophic failure. Within minutes the majority of the dam had disappeared leaving only a central section standing like an island. The flow of water was monumentus forming a 140 feet high flood wave washing away large chunk of the wreck dam as 12.4 billion gallons of water surged down. The wave travelling at around 18 miles per hour destroyed powerhouse number two drowning nearly all the workers and their families who lived nearby. The flood water overflowed the Santa Clarita rivers banks flooding present day Valencia and Newhall. By 1am the entire Santa Clarita valley was plunged into darkness. A temporary construction camp set up by Edison company was washed away killing at least 84. The flood damaged the towns of Fillmore, Bardstale and Santa Paula eventually emptying bodies and debris into the Pacific Ocean 54 miles downstream. The flood water was thought to have killed at least 431 people although this number doesn't count migrant workers, casual labourers and illegal immigrants all of whom would have had no record of being in the region. Many dead were never found or identified including dam keeper Tony Harnishfager. Although his wife's body was found near the dam suggesting that a late night inspection was being undertaken potentially due to the landslide sounds heard by Ace Hopewell. So how did such an impressive structure fail so catastrophically? There was and there still is differing theories on the failure. It is thought that the failure started with the left east abutment suffering a landslide. The left fell side was then swept in front of the dam leaving debris as evidence of the likely side of first failure. A committee appointed by the Los Angeles City Council set about working on an official report into the failure. The key failure was placed at defective foundations and the report essentially said the dam was well designed but poorly executed. With an error in judgement about the suitability of the area's geology as a stable foundation for the dam. The investigation though claimed it was the right western abutment that had failed first owing to cracks discovered leading up to disaster but more modern analyses have speculated differently. Two alternate reports by Bailey Willis and Carl E. Gruntsky support the left eastern side failure theory. They also focused into a phenomenon called hydrostatic uplift. This is where water seeps under a dam and causes an upward force on the dam reducing its effective weight. Although known at the time the phenomenon was not properly understood and a St Francis dam didn't take this into account. Meaning that hydrostatic uplift mixed with an unstable land from historic landslips caused the failure at St Francis. The dam was not rebuilt and for a short while became a morbid attraction for locals to come and collect souvenirs as the single standing part remaining known as the tombstone. The site would be cleared and the tombstone demolished in mid-1929 to detract the strange tourism to the area. Because the Mulholland dam was essentially identical, 330,000 cubic yards was used to reinforce it from the risk of hydrostatic uplift. The Hollywood reservoir that Mulholland holds up was not allowed to exceed 4,000 acre feet of water. Mulholland's career also ended on the night of the 12th and the 13th of March 1928. During the inquest he claimed four responsibility and retired in November the same year. No criminal charges were brought against the designers with the inquest finding no evidence of criminal act or intent. Mulholland would die in 1935 at the age of 79. Thanks for watching, I hope you enjoyed the video. If you'd like to help the channel grow you can by liking, commenting and subscribing. Check out my Twitter for all sorts of photos and odds and sods. As well as hints on future videos. I've got Patreon and YouTube memberships as well so if you fancy check them out and all that's left to say is thank you for watching. Reconnaissance was and still is the backbone of a country's ability to collect information on other nations. One piece of the reconnaissance pie is the use of satellites orbiting Earth, taking photos to monitor armies, navies and even nuclear tests. A malfunction in one such satellite would leave a vast portion of Northern Canada irradiated in January 1978. Today we're looking at the Cosmos 954 and its crash and subsequent radioactivity release. I'm going to rate it here 5 on my disaster scale, not great but also not terrible. The Soviet RawSat program shows that not just the USA was looking at the feasibility of placing a nuclear reactor in space. The program consisted of 33 reconnaissance satellites, which were used to monitor NATO vessel movements using radar low orbit altitude. Because of these requirements, a problem was discovered and that was power consumption. You see, the radar needed power and consistent power, something that solar panels alone couldn't achieve. Not only would shadows of the Earth interrupt operation, but the size of the solar panels would affect orbit. Instead, it was decided to use nuclear power. The USSR wasn't the first to explore nuclear power in space, as the US and NASA got their first with the snapshot program, although later RTGs were picked over the fully fledged reactors for future missions. For the RawSat program, a reactor was designed and placed into operation and this would be called the BES-5 and was a Uranium-235 fast-fishing reactor. The reason for a fast reactor was simply no need for a bulky and heavy moderator. This helped bring the weight down of the entire reactor and radiation shielding to just 385 kilograms and this included 31 to 44 kilograms of enriched uranium. The reactor had six control rods and had beryllium reflectors to reflect neutrons back into the core. The Uranium-235 was more than 90% enriched and generated three kilowatts of electrical power from a liquid sodium-potassium thermonic conversion of 100 kilowatts of thermal output. After its operation, use of the satellite was designed to shoot the reactor to disposal high Earth orbit to prevent it coming back to Earth, although obviously at least once that didn't happen. It is known that at least five satellites experience failures with at least one other incident involving radiation release. This brings us to Cosmos 954 and starts the mission on September 8th 1977. The satellite sat atop a Cyclon-2 rocket being launched at 1355 from the Baikonur Cosmodrome. The satellite orbited Earth around every 19 minutes, but this was changed by December when it began to be erratic deviating from its original orbit. To be fair to the Soviets, after it was decided that the satellite was uncontrollable, officials contacted their US counterparts informing them of the situation, including that the now stricken craft couldn't eject its deadly reactor. The satellite, including the reactor, weighed around 4,000 kilograms, all of which were destined to crash somewhere on the planet. Although it was known that the satellite was uncontrollable, it would take several months for it to re-enter the Earth's atmosphere due to the stable orbit it was following. Initial predictions thought that re-entry would happen near to the middle part of 1978, although these predictions would be proven wrong by January. On the 24th January, the satellite entered Earth's atmosphere while above North-East in Canada. Initially, the Soviets claimed that the satellite must have been burnt up in orbit, but this would ultimately be proved wrong. It was discovered that debris from the satellite had been scattered along a 600km area between Great Slave and Baker Lakes in Canada's northwestern territories. This happened during a 3 minute burn up and was observed from telescopic and visual tracking. Searching for the satellite used a joint recovery team of Canadian and US personnel. Some of the radiation detection equipment and aircraft were supplied by the Department of Energy sent from Nevada. All US units were placed under control, also from the Department of Energy. Immediately after the remains of the satellite had been deposited on the ground, US and Canadian teams scrambled to begin search and recovery operations on the 24th January. The search area was divided into 8 sections initially, but this would be extended to 14 sections after area 5 to 8 showed no debris traces. First on the scene was a 22 man Canadian Radiation Monitoring team. The operation was named Morning Light and it was given this rather cool, albeit homemade, looking logo. A rapid recovery was needed as the radioactive content of the satellite posed a serious hazard to life and the environment. The recovery area posed risks in its own right, mostly in Tundra with very little in the way of landmarks, as all, including rivers, was covered under thick snow. Two C414s arrived from the US with radiation equipment and personnel. The equipment was attached to Canadian aircraft with the first being dispatched from Yellowknife on an initial straight line search of over 500 miles. By 4am, four aircraft equipped with radiation detection equipment had been dispatched. Initially, search areas focused on population centres and main traffic areas. By late January 26, teams had deployed at Baker Lake and Yellowknife in preparation for the aircraft to indicate where to search. Computer predictions augmented the air search by calculating the satellite's reentry route. At around 10pm, a radiation hotspot hinting of a piece of the satellite was discovered by one of the planes just near the Great Slaves Lake and by the 28th, locals in the areas were notified of the potential hazard in the area. Signs were erected in both English and several Indigenous languages. Initially, two men from a team of six explorers on a 15-month dog sled expedition across the Northern Territories discovered a strange object in the Warden Grove Wilderness. When the two returned back to camp, they informed their colleagues. Earlier on in the day, the expedition had received a radio transmission about the crash satellite. The team contacted authorities and a recovery team was dispatched. The piece would be later known as the Antler and had a radiation level of 15 ronkin per hour. By January 31st, several pieces of radioactive debris had been located and isolated by ground crews deployed by helicopter. Once on the scene, the search teams made use of handheld radiation detection equipment. Some of the waste was sent to Yellowknife for initial analysis and others were sent to Edmonton. The search effort spanned over two phases between the 24th of January and 20th of April 1978 and the 21st of April to the 15th of October 1978. As time went on, US personnel were phased out of recovery teams. Here are some of the pieces that were found. A metal drum known as the Stovepipe found in sector 1 was a sizeable piece, although it wasn't radioactive. Four steel plate fragments found in sectors 1, 11 and 12 gave off up to 15 ronkins per hour upon discovery. Over 40 beryllian pieces giving off between 600 millironkins an hour to 100 ronkins per hour on contact in sectors 10, 11 and 2. There are also several other smaller chunks with the highest giving off 10 to 30 ronkins per hour on contact found in sector 10. Although one piece was the hottest fragment discovered, gave off gamma radiation of 500 ronkins per hour near contact.  Not only this, but around 4,000 other smaller particles and debris were found during the recovery work. Non and lower radioactive debris was wrapped in plastic for extraction and higher emitting items were transported offsite in a special shielded container. It was estimated that the total activity over the entire dispersion area would have been around 2,500 curries. This presented around 20% of the calculated total inventory of the satellite. It's really impressive how swift the recovery of the worst of the debris was with collaboration between two countries. Obviously the US assistant had an ulterior motive in the sense of being able to gain intel on the satellite. So with all the expensive recovery operations completed by 1978, who was going to pay for it? You see, if you launch something into space, you are financially responsible for any damage it might cause when it comes back to earth. This was called the 1972 Space Liability Convention, so under the terms the USSR was on the hook for a few dollars. Around 6 million Canadian dollars for expenses was built to the USSR, but they only paid up around 3 million Canadian dollars. The accident didn't stop the raw start program and the USSR continued to launch the satellite types for another 10 years, finally concluding in 1988. A few months after Chernobyl, the Rhine would run blood red as 400 kilometers of the river became contaminated, killing all wildlife within. In November 1986, a fire at the Sandoz Agrochemical Storehouse in the Spreyserhala Industrial Complex, Basel Landschaft, Switzerland would show the risks of poor storage of chemicals in a building not originally designed for this purpose. The incident would also show the side effects of such a fire, as the water used to fight it would mix with the chemical stored and run off into the Rhine and contaminate the nearby soil. I'm going to rate this incident here number 6 on the Painting in Plainly Difficult Disaster Scale. Warehouse number 954 in 1986 was used for chemical storage in Sreyserhala Industrial Complex, measuring 90 by 50 meters. It was originally built as a machinery storage area. Because of this, the building lacked proper smoke detection and sprinkler systems, essential safety systems for chemical storage. The building contained around 1246 tons of phosphoric acid insecticides. Rodicides, herbicides, fungicides, Prussian Blue, emulsifiers, stabilizers, solvents, dodecylbenzene and aminosulfuric acid monophenamine. Now, the cause of the fire has been disputed with even the East German Starzy being accused. But it is thought that the ignition point was Prussian Blue during packaging for storage on the evening of 31st October 1986. The process at the time involved wrapping the pigment in a plastic sheet, shrink wrapped using a blowtorch. During the wrapping, the workmen didn't notice that some of the material was caught by the open flame of the blowtorch. The slow burning material was flameless and smokeless, progressing unnoticed until just after 12 midnight on the 1st of November and emergency services were called. 160 firefighters attended the scene and ferociously fought the flames. The option of letting the warehouse burn down was not allowed due to phosphatine being stored in a nearby warehouse. Because of this, the fire had to be put out as quick as possible to prevent the highly potent poisonous gas from escaping nearby. As such, large amounts of water was used for the firefighting efforts, which would be successfully competed at 3.40am. However, by this time, warehouse 954 had collapsed. Nearby Basil was awoken by an emergency alert as a foul-smelling gas cloud from the blaze was spread across the area. Locals were told not to leave their homes and to close all windows and doors, although this alert was lifted around 7am when the smoke was thought to be non-fatal. It wouldn't be the air so much, as the water that would be heavily polluted, and it would be the very water used to douse the flames that would cause the disaster. The highly toxic mercury compounds were present as fungicides in sea dressings in the warehouse, and were marked with fluorescent red dye Rodamine B. The toxic compounds mixed with the water and flooded the area, making its way into the drains. The Schreiser-Hully Industrial Site had seals that could be closed in the event of an oil spill to prevent effluent from making its way to the Rhine. This is a very useful safety system, although on that fateful night they were not operated. Between 10,000 and 15,000 cubic meters of contaminated fluid flowed into the Rhine, around 30 tons of pesticides, insecticides and around 200 kilograms of mercury were released. Initially the contamination was announced as just non-toxic dye, but this would be proven wrong. On the 3rd of November sandals emitted to the amount of toxic discharge into the Rhine. Just two days later thousands of eels were reported to have died. The pollution by now has spread to around 400 kilometers of the Rhine's water course, and water taken for drinking was cut off necessitating bottled water to be handed out. The pollution waves spread disulfulton and firemeaton. As a side note, estimated lethal dose in humans of disulfulton is less than 5 milligrams per kilogram. Not only the pollution had affected the eel population, but also grayling, brown trout, pike and pike perch had experienced significant damage. Businesses along the damaged waterway shut down. On the 18th clean up works to clear the toxic sludge began, soil was cleaned with special vacuum cleaners in order to prevent it from being washed away with the next flood. Eventually the remains of the contaminants were washed away, and surprisingly the local animal population had already started to replenish itself within three months. The mediation of the fire site where the warehouse once stood and the contaminated soil took about six years were around 2700 tons of semi-combustive material needing to be disposed of. Around 9 tons of pesticides and 130 kilograms of organic mercury had infiltrated the soil surrounding the warehouse. Pollution was detected at depths of up to 11 meters below ground level. Contaminants were removed and sandals installed a shed with a special off gas system for storage. The disaster eroded away public confidence in the self-regulation of the chemical industry in Switzerland. As a direct result from the fire the Swiss government set up a major accident ordinance and chemical safety inspectors. One example of the new regulations was for storage sites to install a basin to collect firefighting water. Some other rules included substances which may react with one another in a dangerous manner, for example large amounts of burnable materials must be stored separately. Based on a risk register around 200 operations with a chemical hazard potential were identified in Switzerland and subjected to the new regulations. The disaster eventually ended up with a net benefit for the local ecosystem as it forced operators and the Swiss government to actively monitor the Rhine. If the proactive measures enacted post-event ever failed a Rhine international warning and a land system were set up with the idea of being able to react almost instantly. Even though no human deaths were linked to the spill the risk to life can't be understated as environmental risks shown at Sandos is only one fire away. Thanks for watching I hope you enjoyed the video. This video is a plainly difficult production. All videos on the channel are Creative Commons attributes share a like licensed. Plainly difficult videos are produced by me John in a sunny south-eastern corner of London UK. Help the channel grow by liking commenting and subscribing. Check out my Twitter for all sorts of photos and odds and sods as well as hints on future videos. I've got Patreon and YouTube membership as well if you fancy supporting the channel financially and all that's left to say is thank you for watching. Architects and engineers strive for striking and innovative design. Minor adjustments in a design are common over the life of a construction project. Although each amendment should be stress tested in order to keep the overall design parameters but sometimes this is overlooked. A hotel in Kansas City would highlight the culture of building maintenance in the 1970s that favoured looks and ease of construction above all else. A disaster would only be one of several structural failures of the era with the 1976 Tent and Dam collapse, 1978 Hartford Civic Centre roof collapse and the 1979 Kemper Arena roof collapse just to name a few. Almost to the day after its completion a hotel in Kansas City, Missouri experienced a structural failure causing the deaths of 114 people. It still remains the deadliest non-deliberate structural failure in American history. Today's disaster shows how something you assume to be safe can be the source of a catastrophic failure resulting in the loss of life. And as such I'm going to rate it here eight on the plainly difficult disaster scale. The suspended walkways are often seen in hotels, shopping centres and museums. Several of these would be a defining feature of the Hyatt Regency's lobby. The Hyatt Regency is part of the Crown Centre complex built by Hallmark Cards adjacent to where most of Kansas City's tallest buildings are located. Construction began in May 1978 and the hotel complex consisted of a 40 story tower, a function building and a connecting atrium area. The total rooms was 733 and on top of the main building sat a rotating restaurant. The hotel also had a 17,487 square foot ballroom and a dedicated exhibition hall. The atrium area was multi-floored and employed free suspended walkways to connect the tower to the function building on the second, third and fourth floors. The third floor walkway was independently suspended from the atrium roof trusses whereas the fourth floor walkway was suspended from the roof framing. The second floor walkway was suspended from the fourth. The atrium measured 117 feet north south by 145 feet east west with a ceiling height of around 50 feet and the walkways ran in a north south direction. The third floor walkway was the widest as it ran to the ballroom area and was intended for large quantities of people. Each walkway was constructed from four pieces made of a steel framed box girders welded together and suspended by one and a quarter inch diameter rods at the end of each piece. Now the original design intended that the rod would be continuous through the fourth floor walkway to the second floor walkway. Under this arrangement each box beam was separately transfer its load directly into the hanger rods and onto the atrium roof. This setup necessitated threads along the whole length of the rod. The fabricator worried that the threads would get damaged during construction and instead suggested an amendment to the design. Instead of continuous rods two separate rods would be used, one running from the roof to the fourth floor walkway with the next set of rods next to it down to the second floor walkway. This had an unwanted side effect and that was the transference of force leading to the fourth floor having to hold up both itself and the second floor. The weight on the roof would still be the same but a nut at the end of the first rod would have to support two levels instead of the one original in the design. The fault was not picked up by the designers a concrete slab was placed on top of the metal frame and formed the walkway. Tempered glass plates held in extruded aluminium gaps and the base of the walkway formed the handrails. The walkways were approximately 120 feet long and weighed approximately 64,000 pounds. Construction completed in 1980 and on the 1st of July that same year the hotel opened to paying customers. This leads us onto the 17th of July 1981. A little over a year after its opening the hotel was hosting a tea dance to between 1200 to 2000 people in the atrium. The event started at 3pm, by 4.30pm most of the seating in the atrium area was occupied and many started to spread throughout the various levels. The busy atrium was brimming with people and because of this many had made their way up to the walkways for a better view of the evening. By 7pm the evening was in full swing and the band returned from a break to begin to play. Around the same time spectated on the 4th floor walkway experienced a strange and unnerving metal scraping sound. At 7.05pm the 4th floor gave way falling onto the crowded 2nd floor. The impact pushed both floors onto the atrium 1st floor below. Many bodies were buried beneath the steel, glass and concrete with many still alive. At 7.08pm the emergency call was sent out to the Kansas City Fire Department. Within minutes Fire Department 1st responders arrived on the scene and requested additional help and equipment to launch a rescue effort. Nearly 20 minutes post collapse a forklift was requested before the end of the first hour more than 100 firefighters and emergency workers were involved in the rescue operation. The total rescue operation would last 14 hours well into the afternoon of the 18th with the recovered dead bodies stored in a makeshift morgue in the exhibition hall. Any available space away from the atrium was used for triage of the wounded. Walking wounded made their way to A&E whilst more seriously injured were treated on site. One such person had their leg amputated by a doctor with the use of a chainsaw. The hotel's sprinkler system was damaged during the collapse and a real risk of flooding was feared. In the wake of the disaster blood centers received hundreds of donations and anyone who could help did with the rescue efforts. With over 200 injured and a total of 114 dead how could the collapse have happened in such a modern building. With a shocking disaster in a new building investigators were faced with a failed structure and the question how. The NSB on a national bureau of standards began their investigation on the 28th of July after a court order covering protective custody of the debris was given to the investigators. Initial measurements, inspections and photographs were taken of the debris and remains at the 4th and 2nd walkways. They found something strange on the 4th floor box sections. The seam weld was strangely bent in a line near where the rods met the walkway, the same part that had been redesigned by the fabricators of the rods. What was also odd was that a number of the washers used at the nut of the rods of the 4th floor were either missing or severely deformed. The theory that was positive was that the stress on the cross beams of the 4th floor had split the welds on the beams seam allowing the floor to slip on top of the 2nd. To prove the theory, the MBS conducted a number of stress tests on identically fabricated segments. The MBS found during its investigation that the constructed walkways were considerably less capable of holding up the design loads specified by the Kansas City Building Code. They also concluded that the rods of the 4th floor walkway had failed causing the total collapse, most notably at the box beam rod connections, where the design had been changed by the fabricator. It was predicted that the original design of a continuous rod was 90 kilonewtons, whereas the actual installation of the interrupted two rod arrangement was 181 kilonewtons, doubled the designer's spec. It was also found out that the continuous rod arrangement would have handled the loads on the walkway on the 17th of July. Although the disaster point was the interrupted rod arrangement, the core failure was in the communication between the fabricator and the designer. The designers had assumed that the drawings made by the fabricator were the final version and checked out. However, if anyone had actually recalculated the loadings then it would never have got off the drawing board. The event became a cautionary tale for future construction projects and the hotel was reconstructed at a cost of around $5 million. Lawsuits totaling $3 billion were sought, with only around $140 million being paid out over the following years. The design firm, Jack G. Gillam, and associates in charge of the hotel's construction was found not criminally responsible, although this would be little consolation, as the company lost its engineering licenses in the states of Missouri, Kansas and Texas. Jack G. Gillam, haunted by the guilt of the event, would take lectures at universities showing the repercussions of his responsibility and the failings in construction of the hotel, hoping that others would learn from his unfortunate oversight. History has a habit of repeating itself when you don't learn from your mistakes. For a second time, the plutonium facility at Rocky Flats would experience a devastating fire. The event would be another chapter in the saga of pollution at the site. The Rocky Flats plant is up there as one of the worst nuclear industry sites for long-term contamination. The facility would experience not one, but two plutonium fires. Now, before I start, I strongly recommend that you watch my video about the 1957 Rocky Flats fire, as it gives a bit more background to the site, and was the worst of the two fires in regards to contamination release. Although it less a disaster, today's subject, the 1969 fire, was the catalyst for the wider public being aware of the site's shortcomings with radioactive containment. As such, I'm going to rate the Rocky Flats plant as a whole, as seven on the painted, plainly difficult disaster scale. The Rocky Flats nuclear bomb factory was located 16 miles northwest of Central Denver. Our story begins in 1957, around the same time as the remediation works to clean up the first fire were undertaken. A new trigger design was beginning to be employed in US nuclear weapons. The new triggers had different shapes of plutonium with closer tolerances, necessitating more rolling, forming and machining than early years of weapons production at the damaged building 77. With the main fabrication building running at reduced capacity, a new complex was decided to be constructed, completed in 1958. The complex was two buildings, 776 and 777, one for manufacturing and the other for inspection. The new building was able to cope with the more intricate manufacturing process for plutonium triggers. After a couple of years of operation, the dividing wall between the two buildings was removed for ease of production. The building was a two-storey structure with a partial basement. The main floor had 135,000 square feet, the second floor contained 88,000 square feet and the basement boasted 600 square feet. Similar to the process used in building 77, the plutonium triggers had to be founded and milled to the correct shape, all of which was done within shielded glove boxes with plexiglass windows. Releases of radiation wasn't just confined to the two rocky flat fires. As between 1964 and 1967, toxic cutting fluid contaminated with particulates of plutonium and uranium were stored in 55 gallon drums on pad 903. Over the years, the drums had corroded on their underside, leaking the contaminated effluent into the soil around the storage area. With some of the waste mixed with dust, between 1.4 and 15ci or 19 to 208 grams of plutonium dust was released contaminating offsite areas to the south and east, necessitating the pad to be paved over with asphalt. Leading up to 1969, over 10 modifications to the complex were undertaken as production grew. Four principal glove box systems existed at building 776, 777. These included North Foundry Line, the South Foundry Line, the Centre Line and the North-South-East Machining Line. All production operations were carried out in glove boxes that were interconnected. This leads us on to the 11th of May 1969, and a small smouldering fire in one of building 776 or 777's glove boxes that were turned into one of the most costly industrial accidents up until that point in US history. At around 2pm, a smouldering began in an open plastic can containing plutonium. As we saw in 1957, the material slowly burns, much like charcoal and again the cause of the spontaneous ignition is not completely known. Eventually the smouldering ignited the plastic, causing a much bigger fire as other materials set alight. The fire was spread about by the glove box ventilation systems. There were very few fire breaks in the line, causing damage to a large proportion of the building. The filters employed in building 776 and 777 were different from the ones in the 1957 and were less flammable, and had 6 banks of high efficiency particulate air filters or HEPAs. This time around the filters worked more efficiently, capturing a large amount of contaminants. By 6pm, the fire was largely contained and fully extinguished by 8. During the fire, 4 filters were severely damaged, leading to a release of material out of the building vent stack. It was estimated that between 0.14 and 0.9g or 10 and 60mci of plutonium 239-240 had escaped into the atmosphere during the fire. The most contaminated area was behind the vent stack on the building's roof, with plutonium all over the structure, and some was tracked in and out of the building by firefighters during the fire. Some plutonium was carried off site by winds, although it is not known by the exact amount. Again, like in 1957, the most exposed were people outside exercising at the time of the release. This is because plutonium predominantly emits alpha particles, which are only damaging to the human body if ingested, for example through breathing. The fire drew the attention of independent radiochemists at the National Centre for Atmospheric Research. Some of the soil on site were taken, and unsurprisingly, plutonium traces were found to be 400 times above the average levels. Officials at the plant were questioned, strangely denied the contamination was from the fire, and instead emitted to the 1957 fire and the release at area 903. And thus the 1957 fire and contamination were now known by the public. After the fire, a two-year path for remediation was laid out, and production was moved to another building, and waste disposal operations began. Cleanup activities were completed on October 18, 1971, and by 1972, all manufacturing was transferred to building 707, with 776 and 777 converted to a waste disposal area. No serious injuries were reported from the fire, apart from one firefighter who inhaled a sizeable amount of plutonium and 32 other employees, all of whom were treated for contamination. All were reported to have made a full recovery, although the effects would have been long-term illnesses such as cancer long after the incident. So take that with a pinch of salt. The damage to building 776, 777 would cost upwards of $26 million to dispose and repair. The disaster had a positive change, however, in the way that Rocky Flats operated. The event pushed forward safety system improvements, including the installation of water sprinklers, firewalls to control the spread of fire, and the use of inert gas for plutonium operations to prevent spontaneous ignition. It's just a shame that all that wasn't brought in after the 1957 fire. Thanks for watching, I hope you enjoyed the video. This video is a plainly difficult production. All videos on the channel are Creative Commons Attribution Share alike licensed. Plainly difficult videos are produced by me, John, in a sunny south-eastern corner of London, UK. Help the channel grow by liking, commenting and subscribing. Check out my Twitter for all sorts of photos and odds and sods, as well as hints and future videos. I've got Patreon and YouTube membership, if you fancy supporting the channel financially. And all that's left to say is thank you for watching. Barges towed by tugs are a common sight on the waterways of the world. So much so, they are often overlooked in the amount of damage that they can cause. An important thoroughfare across the Arkansas River would collapse from a bridge strike by two barges pushed by a tug. The disaster showed the responsibilities of such users of rivers and would result in the loss of 14 lives, 11 injured and a 580 foot section of bridge plunged into the river below. Imagine driving across a bridge only to have it collapse below you. Definitely the field of nightmares, but likely something that you will never experience. However, in a main morning in Webber Falls, Oklahoma, United States, this very scenario would play out, putting a spotlight on the risks of waterway transport. Sadly, the event would be due to an unknown health condition of the boat captain. But regardless of the cause, it shows how vulnerable a bridge really can be. Scarily the collapse wasn't in the early part of the last century, but instead within living memory just over 18 years ago. Today I'm going to rate this disaster here 6 on the Patented Plain Difficult Disaster Scale. This is due to it being deadly, but not having too much in regards to environmental implications or long-term health effects, apart from the obvious mental trauma of the survivors of the disaster. Our story starts in 1967 with a newly constructed I-40 bridge spanning the Arkansas River near Webber Falls. The I-40 bridge is a twin girder continuous span bridge consisting of 13 concrete sections that were 7.5 inches thick. Supported by steel girders and a steel superstructure that was in itself supported by 12 reinforced concrete piers and two bridge abutments. During the construction design of the bridge considerations were not given for lateral loads caused by collisions and this was standard for the era. On the west piers 1-4 supported the bridge and to the east piers 5-12. Each pier consisted of three main sections with section 1 attached to the bridge footing with section 3 supporting the bridge span. Bridge strikes or collisions as they are known were obviously a known risk by the early 2000s as such impact mitigation was provided in the form of reflectors and lights. These consisted of red lights and red reflectors affixed to the steel girders marking the location of the main span piers for north and south shipping traffic. With green lights and green reflectors marking the center of the main span the main span was between pier 4 and 5. A green boy was located 0.35 miles from the bridge marking the upbound left side of the channel. In case all that didn't help the bridge had pier protection sails on the northern approach for pier 4 and 5 only. Extra protection consisted of 10 inch by 18 inch by 89 feet long treated wood planks attached to the inside face of piers 4 and 5. These were installed in the 80s due to a number of unreported bridge strikes in the late 1970s resulting in superficial cracks in the concrete structures. The cracks were repaired with grout to prevent progression of the damage. The Robert Wylove was a diesel driven inland river tugboat operated by the Magnolia Marine Transport Company. The vessel was built in 1955 and the twin screw tug was originally named Caroline under its first owner. She was sold in 1992 to MMT where she undertook upgrade works to her engines. Robert Wylove was 104 feet long with a width of 30 feet. She had recently had her dry dock inspection in March 2002 and was given a clean bit of health with no issues with her control equipment. In May 2002 she was pushing two barges also owned by MMT named MM60 and MM62 both built in 1999. Both were identical in size at 297.5 feet long with a width of 54 feet. They displaced 402.6 and 427.4 long tons respectively. The section of the river that the I-40 spanned was controlled by LOX as it was part of the MacLennan Care Arkansas River Navigation System which itself formed part of the United States inland waterway system. Due to this the river had little in the form of current, meaning water traffic could make easier progress throughout the network. At 3.40 in the morning of the 19th of May 2002 the tow boat Robert Wylove departed on route to Katuna. She was pushing two empty barges and on the 23rd of May the vessel and her barges entered the M Khan system. At 18.40 on the 25th of May the alternate captain was relieved by the regular captain and took over the watch being relieved himself by the pilot at 22.45. The regular captain was 60 years old and had been in charge of the Robert Wylove since February 2001. He had over 40 years of experience through his marine career. The pilot was then relieved by the captain at 5.30 am on the 26th. You see the shifts on board most vessels like this are 6 hours long, meaning 6 on 6 off. In the interest of good journalism I tried out this type of shift pattern for one of my days off and it's pretty brutal but maybe you just get used to it. At around 7 am one of the crew members went to the wheelhouse to clean up. After completing his duties he chatted to the captain for around half an hour. The usual approach to the I-40 bridge was along the centre of the river guarded by boys. GPS data collected post event showed that the vessel followed the usual path until around here, where she went off course. Would the vessel travelling at 6.7 miles per hour? The captain later told investigators that he remembered passing the boy to port and using a few degrees of left rudder to align his toe through the navigation span at the bridge. At this point he blacked out and the Robert Wylove was just 4 minutes away from impact. At around 7.45 am the toe struck pier 3, about 201 feet west of the navigational channel at around a 56 degree angle. Pier 3 was not designed to be crash resistant. This was due to the main navigation route being between 4 and 5. And because of this it collapsed taking the bridge span with it. The collapse damaged pier 2, in total over 500 feet of roadway disappeared into the river below. Some of the debris landed on the barges with the crew on board witnessing several vehicles drive off into the void. Nearby participants of a fishing tournament witnessed a mayhem and phoned 911 with one of the party firing a warning flare into the sky. By now the captain had regained consciousness, witnessing the incident in front of him he sounded warning blasts on the boat whistle. In total 8 passenger vehicles and 3 tractor semi-trailer trucks had fallen into the river or onto the collapsed portions of the bridge span. 3 people who had escaped their vehicles after falling into the river had managed to get to shore with the help of the recreational boats in the area. At 7.48 am the first of the emergency responders, members of the local police arrived on the scene. 6 ambulance responded with the first arriving at 7.56. 11 local fire departments, 10 EMS departments, 8 emergency management agencies, 7 state agencies and 7 federal agencies would all assist. A total of 58 local, state and federal agencies responded to the accident. The Robert Y Love did not sustain any damage due to it being at the back of the tow. However both barges were severely damaged, costing over $275,000 to repair. But obviously that would be the smaller amount in terms of damage cost. The I-40 bridge, damage and associated costs came to just over $30 million. The I-40 was closed for 65 days whilst repairs and reconstruction work was undertaken. The bridge was struck in an area not reinforced due to the intended traffic flow being between the 4th and 5th piers, which was the structural failure point of the collapse. But what was the actual cause? The person in control of the tug had navigated the waters many times over their career and was familiar with the area. He obviously was experienced with the amount of years working in that industry, which leads on to the question how did the tow make contact with the bridge? The captain of the tug reported that he had experienced a blackout on approach to the bridge. After drug and alcohol tests showed up negative results, investigators looked for any possible medical explanation. Medical experts suspected a condition called syncope, which can cause a lack of blood flow to the brain. Usually in an incident like this the person would fall to the ground, which would then allow blood to flow back to the brain, allowing consciousness to recover quickly. In the case of the captain and the wheelhouse's limited space, he didn't fully reach the floor. Instead he was supported in a crouching position, leading to an extended period of unconsciousness. In a week leading up to disaster, he had felt a number of periods of dizziness, but had attributed it to fatigue. It was found that in the 72 hours leading up to the event, the captain had a sleep debt of around 12 hours. Post accident, the captain was subjected to several tests to investigate this theory, with abnormal heart rhythm and clogged arteries discovered. Both can be causes of syncope. Traffic resumed on the 29th July 2002 in a record turnaround time. The NTSB recommended a bridge warning system for road users and a wheelhouse alert system for marine vehicles. Thanks for watching, I hope you enjoyed the video. Would you like me to cover more bridge disasters like this? Let me know in the comments. This is a plainly difficult production. All videos on the channel are Creative Commons Attribution Share alike licensed. Plain difficult videos are produced by me, John, in a sunny southeastern corner of London UK. Help the channel grow by liking, commenting and subscribing, and check out my Twitter for all sorts of photos and odds and sods, as well as hints on future videos. I've got Patreon and YouTube membership as well, so if you want to support the channel financially, you can do through there. And all that's left to say is thank you for watching. Today's subject shows the pitfalls of when little fault is given to safety design and operational procedures of an electronic accelerator. The National Centre for Scientific Research is an organisation that runs several facilities in Vietnam, which use ionising radiation for research. But we'll be focusing on just one of these facilities. I'm going to rate this subject here free on the patented plain difficult disaster scale. This is due to the incident only really affecting one individual, but it's going to have a six on the historical legacy scale due to it being a vital lesson for operators of these types of machines. The Hanoi Institute of Nuclear Physics will be the setting for today's subject, based in Vietnam. The facility worked on photon and neutron induced nuclear reactions, material analysis using photon and neutron activation, x-ray fluorescence spectrometry, and geology, medicine, agriculture, industry and environmental applications of nuclear techniques. The HINP operated two electron accelerators, gaining its first in 1974. The second, a microtron MT-17, was attained in 1982. The first electron accelerator by the early 90s was no longer in operation due to parts shortages. The MT-17 was originally built in 1973 at the Joint Institute for Nuclear Research at Dubna, USSR. It produces neutrons and x-rays from electrons accelerated up to 15 MeV. In 1980 the JINR stopped using the unit and in 1982 shipment to Hanoi was arranged. The JINR and the HINP had a good working relationship with an exchange of training and equipment. The area that would house the MT-17 was designed to copy that of the Dubna facility, although the only manual shipped with the machine were supplied in Russian, causing a bit of a problem setting up. The accelerator room walls had a thickness of 1.8 meters, and leading into the room was a hallway called the maze and this had wall thicknesses of 1.4 meters. No audit of the completed installation safety systems or dose rate surveys outside the room to assess the efficiency of the shielding was conducted. Practice for the operator's radiation monitoring skills was limited to experience gained from Dubna. Due to the reduced funds of the Institute, no active radiation monitoring was undertaken. Before we get onto the accident, let's have a brief look at the MT-17 and how it works. The MT-17 electron accelerator could produce x-rays by accelerating an electron beam to 15 MeV into a 2mm thick tungsten plate. The unit can also produce neutrons by bombarding a uranium target with an electron beam. The electron beam is created in a magnetron, guided along a tube to a cathode and accelerated in a circular orbit using magnets and directing them to the appropriate target material. The control console didn't have a key to switch on, but was considered safe at the time due to all the writing being in Russian, which is a questionable safety feature. Samples can be transferred into and out of the accelerator room remotely, if desired, through a hollow plastic tube that leads from the accelerator room to a counting room. When an item is to be irradiated, the tube and inside the accelerator room was placed manually in front of either the tungsten or uranium targets and compressed air was used to deploy or retract the sample. No timing device or dose control cutout was installed at the facility for the machine and instead radiation dose times were counted on a wristwatch. Radiation measurements were taken from a detector positioned halfway down the May's wall with no indication in the accelerator room itself. There was no interlock on the door that led to the accelerator room, meaning anyone could walk in unimpeded during a radiation and word of mouth was used to inform staff of an experiment being in operation. There were however immediately outside the accelerator room door and in the corridor to the control room signs that became illuminated when the beam current was switched on. And bizarrely, radiation monitoring was never undertaken outside of the accelerator rooms, meaning no one knew if the shielding walls were actually effective at all. Apart from short training courses, no in-depth instruction was ever given to safe working practices leading to a non-safety focus work environment. Which leads us on to the 17th November 1992 and one employee at the HINP would experience a sharp end of safety complacency. On the morning of the 17th November 1992, a research group led by the facilities director were doing an experiment on irradiating a gold ore sample. The air compression based sample extraction system was not being used that day due to the sample only needing to be irradiated for around an hour. Initially, the day starts off successfully with the first sample experiment going to plan. A second sample was placed in front of the tungsten target by a three-person team led by the facilities director. The team walked towards the control room out of the maze area along the hallway. The director asked one of his assistants for some soap and turned to walk towards the courtyard area where there was a sink. The assistant had to pass the control room to collect some soap and on her journey she said to the operator that the experiment was ready to start. What she didn't know was that the director questioning his placement of the sample had re-entered the MT-17 room. He repositioned the sample using his hands and was only around three to thirty centimetres from the target. Upon returning the assistant couldn't find the director but did find the MT-17 door open. She shouted out for him but received no reply. Meanwhile the director was in the room using wax blocks to secure the sample and at that moment the magnetron was powered up and a noticeable sound could be heard. The director had not noticed the implications as all the equipment and air conditioners running created a distracting ambient noise. Upon discovering the MT-17 door open the assistant called inside but again no reply as her voice was drowned out by the background noise. She ran to the control room and told the operator to shut down but it was too late and the accelerator had been in operation for at least two minutes with a beam current of six microamperes. The assistant and the control room operator made their way to the MT-17 room to find the door open and upon entering found the director still handling the sample. Calmly the director exited the room and after a few minutes later after realizing what had happened he proceeded to the measurement room to use the germanium crystal gamma spectrometer. A peak of 511 kev was showing up. Not really knowing the implications nothing much else was done apart from another measurement of the director's hands in the gamma spectrometer but no peak appeared. Staff at the facility knew of the accident but little more thought was given to its implications and work seemed to carry on as normal. The director continued on with his day and when returning home felt a strange sensation in his hands. Being a sufferer of arthritis he pegged a new feeling down to that and washed his hands with warm salt water. He carried on his daily routine as usual going to work for around eight days. Ten days post exposure he went through his annual medical check and even then nothing unusual was spotted. As his hand began to swell up the director requested a hospital examination. Over two weeks post exposure he was hospitalized with the quite obvious serious injury he had suffered and only then it was concluded that the damage was due to radiation. Day 24 post exposure the patient had experienced difficulty in moving his fingers due to the swelling. Initially antibiotics and lotion was used but eventually the skin had begun to develop necrosis. It wouldn't be for nearly two months post the event that the official regulatory body in Vietnam, Vinatom, would hear of the accident. A report into the incident was requested which was delivered on the 2nd of February 1993. The National Centre for Burns who were treating the director predicted a dose near 25 grey but in March the same year dose rate measurements estimated that he had received between 20 and 80 grey depending on the actual time the beam was on his hands. The reference a whole body exposure of 5 grey can lead to death within two weeks. After these results Vinatom requested assistance from the IAEA. Interestingly Frog's skin was used to try and heal the hands but 50 days post exposure on the 5th of January 1993 the first skin graft was administered. Day 127 post exposure an IAEA doctor examined the hands of the patient and an estimate of 50 grey of exposure to both hands was suggested and she recommended amputating one of the most affected fingers. The patient was then under the recommendation of the IAEA transferred to a hospital in Paris due to his worsening condition. After admission on day 159 on the 24th of April his left hand showed signs of improvement but his right hand had a severe infection at the amputation site of the finger. On day 226 the 30th of June his forefinger on the right hand was amputated in the hope of saving the thumb but necrosis and pain continued. After months of pain skin grafts and necrosis his whole right hand was amputated at the wrist. After the successful surgery he was discharged to outpatient status and stayed near the hospital in Paris but three months later latent radiation effect began to spread to his left hand. Eventually another two fingers would need to be amputated before his eventual return to Hanoi in July 1994. The aftermath and on the recommendations of the IAEA a magnetic lock was installed to the accelerator room door which would if not closed give a warning to the control room. A previously faulty warning bell in the accelerator room was repaired and this could alert anyone that the beam was about to be in operation. The IAEA also recommended about automatic pre-warning, automatic warning, emergency cut out buttons, door interlock system, search and lock up system, area radiation monitors, warning signs and a closed circuit television system being installed at the facility. As well as all this a proactive approach to safety training had to be implemented. An accident such as this shouldn't have happened but unfortunately lack of knowledge and funds allowed a severe lack in correct safety systems and procedures. The victim although unlucky with the loss of a hand and fingers it could have ended up with a whole body dose leading to slow and drawn out death similar to that of Hisashi Auchi just a few years later. When you think of a metro network images like this might pop into mind. I know for me it brings back memories of the Jubilee line at 6.45 am at Canada Water. If you've been there then you know what I mean. Being so close to your fellow travel compatriots, apart from being a great way to spread coughs, colds and a certain current event virus it is also a valuable target for people with nefarious reasons. Although I've painted a London Underground style picture today we're actually looking at the Tokyo subway and an incident in 1995. The Tokyo Metro is the gold standard for efficient railway operation and is something to really gaze in awe at. The frequency and predictability of the trains would be its Achilles heel in attack however. You see the more efficient a network is at transporting people the more efficient it can be at transporting a biological weapon meaning a higher exposure rate to the public. Now we'll go into more detail in a bit but the weapon of choice Sarin can be very effective on board a very packed subway train and as such I'm going to rate this disaster here 8 on the patented plain default disaster scale. This is due to the potential that the attack could have had for many more deaths if it wasn't for the poorly manufactured Sarin and I'm going to rate it here 6 on my historical legacy scale as lessons have been learned but subway networks around the world are still vulnerable. Before we go on to the attack let's have a look at who was behind it. Now I'm not going to go into too much detail here as we don't normally talk about anything religious on plain difficult however there is a great episode of the Necronomapod on the Umsham Rikio Japanese New Religious Movement and this was who was linked to the attack in 1995. So I'll be referring to the perpetrator of the attack as the group or other nondescriptive terms and I won't be mentioning any of the attackers by name as well. The group started in 1984 in a one bedroom apartment in Tokyo's Shibuya ward starting off as a yoga and meditation class. The movement developed into a new religious organization during the 1980s. It gained official status as a religious organization in 1989 and attracted a large number of graduates from Japan's elite universities which in turn helped boost its popularity. In 1993 the group started manufacturing their own nerve agents after a small laboratory in a Kamikwishiki complex named Satyan 7 was built in November 1992. During this period they had tried to make automatic rifles and anthrax as well as many other different types of weapons for an attack on the Japanese people to try and overthrow the government. By 1995 the group had been responsible for several incidents including assassinations, the ex-attacks and an earlier sarin attack. Fearing an attack on their compound the group decided to carry out a massive attack on the Tokyo population using sarin to try and distract the Japanese authorities. Before we have a look at the event let's find out what sarin is and how it is deadly. Sarin is a colourless and odourless extremely toxic, synthetic, organophosphorous compound. It is classed as a chemical weapon and depending on the dose can kill you between 1 to 10 minutes after exposure. The Asian is thought to be up to 26 times more deadly than cyanide and is toxic to human beings on both ingestion and skin contact. Meaning people assisting victims can also be affected. After exposure the victim would experience the following symptoms. A runny nose, tightness in the chest and constriction of the pupils. Later on difficulty breathing and nausea would follow. As they continue to lose control of bodily functions vomiting, defecation and urination may be experienced by the victim. Sarin is an inhibitor of acycolinesterase which is an organic chemical used in the brain and is released by motor neurons of the nervous system to activate muscles. The agent has been used by many countries since its discovery in 1938 and its first known victim was Ronald Madison in Port and Down. Maybe I should cover that in a future video. Sarin is very unstable and evaporates from liquid to gas quickly but also decays in a relatively short amount of time. Meaning it is very deadly but not for long. The satyan 7 was a very small but very well equipped and stocked manufacturing facility. But this did not ensure safe operation as a site experienced several accidental releases of various agents. This led to many of the workers falling ill to mild sarin exposure. But in the poor conditions the group members managed to make 3kg of sarin which was used in the Matsumoto attack in 1994. As a little side tangent this attack used a converted refrigerator truck to pump a cloud of sarin to its target which is absolutely insane. The attack killed 7 people in the aftermath and an 8-14 years later with over 50 injured. Sorry a bit sidetracked there. With a tip off that the compound would be raided frantically made more sarin for another attack in the hope of creating a distraction to local authorities. Due to the rushing of the production process this time around the quality was only half of that at the Matsumoto attack and instead of a colourless liquid had a brownish hue. Around 30kg of the agent was manufactured and placed into plastic bags ready to be used in one of Japan's worst terrorist attacks. This leads us onto the attack on the Toko subway on the 20th of March 1995. Five attackers and five getaway drivers set out to release the deadly agent into several trains on the Toko subway in the rush hour peak.  Three lines were selected, the Chiyoda line, the Marunouchi line and the Hibiya line. The attackers had set direction on where to puncture their bags on trains heading in particular directions. This was to ensure that the attack happened at the same moment on five different trains that were travelling to the centre of Tokyo to create maximum damage. After the bag was punctured the sarin liquid would begin to evaporate and its fumes would permeate the railway carriages affected by the attacks. Not long after the attackers had fled their respective targets the trains passengers started to feel the effects of the agent. The worst train for casualties was Hibiya line A720S, the south west bound 0743. The attacker on this train made the most amount of punctures in his packets of sarin. Not long after the assailant escaped passengers started to feel sick. Noticing the large liquid soaked package on the floor and assuming it was the culprit, one of the passengers aboard the train kicked the packets onto Kodon Macho station's platform. With a puddle still on the floor the train continued on and more passengers were feeling ill. By the time the train reached Tejuki station multiple casualties piled on the platform. Eventually all the five affected trains were taken out of service for investigation and the cause of the passenger injuries. Many of the injured suffered from vision problems with many experienced convulsions, shortness of breath and nausea. Many of the affected stations were strewn with injured as they awaited treatment and transportation to hospital. In over over 600 were transported to hospital with nearly 5000 making their own way for treatment across Tokyo's medical centers. Some of the less affected actually went to work with many only realising their exposure after reading news reports. During the event many of the victims were secondary exposures from people already exposed with the agent amongst their clothes or on their skin. Not knowing the cause of the attack meant that subway workers inadvertently were also affected leading to mass panic and chaos on the platforms. In total three lines were affected necessitating decontamination works. The efficiency of the subway system meant that the affected victims were kept in service longer than they should have leaving more people open to exposure. Medicine for sarin poisoning had to be shipped in from smaller towns where it is used as an antidote for herbicide and insecticide poisoning. The bullet train network was used for the transportation. Just over a month after the attack for compound owned by Um Shinrikyo was raided by the police and JDF in an armed show of force, fearing a violent retaliation from the group. In total all of the perpetrators were caught with the last being arrested in 2012. In all five of the attackers were sentenced to death and were executed by hanging along with other key leaders of the group in 2018. The remaining perpetrators of the attack were all given life sentences and these were mainly the getaway drivers. Only one of the people that actually set off the sarin attack on the subway network in 1995 showed remorse and because of this he was given a life sentence. The attack shows how mass transit networks are vulnerable as their design efficiency in transporting people leads to less strict security controls. I mean imagine going through airport security for traveling on the tube. This video has been a bit of a different subject from normal but I thought it was really interesting. So thank you for my patrons for voting for the subject. Thanks for watching, I hope you enjoyed the video. This is a plainly difficult production. All videos on the channel are Creative Commons attribution share alike licensed. Plainly difficult videos are produced by me, John, in a sunny south-eastern corner of London, UK. Help the channel grow by liking, commenting and subscribing. Check out my Twitter for all sorts of photos and odds and sods as well as hints on future videos. I've got a Teespring store if you fancy wearing some of my T-shirts and I've also got Patreon and YouTube membership if you fancy supporting the channel financially. And all that's left to say is thank you for watching. The Railway's safe operations are taken for granted especially in the UK where very few serious accidents or collisions happen. This is due to over two centuries of safety innovations evolving the industry. The UK has complex signalling systems to ensure that two trains aren't allowed on the St Peter Tracker one time. However this rule has been broken by either operator error or infrastructure failure and most of the time the error doesn't lead to a catastrophic outcome. But a poor wiring installation would cause a free train collision costing 35 lives and over 400 injured. In the modern railway, one thing above all else is paramount and that is safety. This is quite an obvious statement as trains are large metal boxes travelling at speed which are filled with hundreds of people with a collective friction area of the wheels not much larger than a pound coin. The low area of contact between the wheels and track means that they are very efficient which is great for carrying heavy loads at lower energy costs than road vehicles. Today's disaster is not important just because of the human and infrastructure cost but it is the cornerstone to modern day health and safety regulations for safety critical work. This video is about the Clapham Rail Disaster on the 12th of December 1988. Today I'm going to rate the Clapham Rail Disaster here five on my Painted to Plain Difficult Disaster Scale. This is due to the disaster not having a wider environmental impact but it is an eight on my historical legacy scale. Safety critical systems are usually designed to revert to a safe state in the case of any breakdown of operation. This is known as failsafe. An example of this is electromagnets holding control rods out of a reactor core. In the case of loss of power the rod falls with the help of gravity stopping the chain reaction. On the railway this is no different. If a signal fails it reverts to danger or red. This is usually a given but in the closing years of the 1980s a simple wiring fault would bypass the failsafe state. But before we get onto the disaster let's have a very brief look into UK Railway Signalling and I mean a brief look as I could probably make a whole documentary if I was allowed to go into a deep dive. Trains are very efficient as I said earlier which is great for fuel usage but can be the achilles heel of rail vehicles. You see less friction means less ability to stop and I really mean less ability. If you can see another car slam on the brakes in front of you when you're driving you have a pretty good chance of stopping well before you become a human can of spam. This is because you have a lot of friction between your grippy tyres and a nice skin shredding asphalt. Trains don't have this so you can't rely on line of sight to stop two trains becoming one big squashed one and to allow safe stopping signalling is used. In basic signalling principles the track is broken up into multiple sections where only one train is allowed one section at one time. Each block section is protected by a signal behind it. There are also overlaps which are an extra section of track giving an extra area for safety in case of an accidental entering of an occupied block section. The UK on many of its main lines use four aspect signalling this enables trains to be at a safe braking distance from one another and can give the driver advanced information of where the next train ahead is. On lower speed subsidiary lines and on London Underground excluding the automatic ones three and two aspect signalling is used but for today we're not going there. Four aspect signalling can show you, you guessed it, four indications. The first is proceed or green this means that at least three signal block sections ahead of you are clear and you can proceed at line speed. The next signal is preliminary caution or double yellow meaning the next signal is at caution and you should probably be thinking about slowing down in preparation for a stop further down the line. Then there is caution which tells you that the next signal was showing danger or stop so be prepared to stop at the next signal. And finally there is danger stop shown by a red. This is pretty simple as it means stop as there is most likely another train ahead of you or the route you are going to take is not set yet. Right well that was a very brief and quick lesson on UK signalling. If you fancy a more in-depth video check out this charmingly dated BR video on the subject. The next thing to look at is the disaster itself and our story starts off with signal Whiskey Alpha 25 has been abolished and a new four aspect automatic signal Whiskey Foxtrot 138 printed in a weekly notice for drivers. Although signalling changes are not a really regular occurrence it is not unheard of and would largely be taken as it was an important but minor change in the grand scheme of things. Likewise for track workers tasked with fitting the new signal it was a regular occurrence for them presenting little in the way of a challenge for someone in that line of work. The new signal would be the cause of the disaster after installation of other wiring during a period of weekend engineering work. The fault would only show itself on a weekday morning rush hour as Clapham junctions saw short headways between trains. You see during the weekend less trains run meaning it is less likely for them to stack up at signals and traffic would be more free flowing. The location of Whiskey Foxtrot 138 was the penultimate signal before Clapham Junction in a railway cutting heading towards London. The previous station was Erlsfield. The signal was meant to protect trains that were standing just outside Clapham whilst they awaited a free platform. The final signal before entering the station's platforms was controlled by the Clapham Junction A signal box. Where trains movements were controlled and more importantly where the relays and interlockings for the signals in the area were housed but a fatal wiring error meant that the signal would not display a stop aspect after a train had passed it which basically defeated the whole point of it being there. On the early morning of the 12th of December 1988 multiple trains had passed Whiskey Foxtrot 138 with no issues. Due to the frequency of five minutes between trains all drivers were seeing green signals. Until the beginning of the morning rush hour leading up to 8am as more trains were going to London the pinch point of Clapham Junction's time between trains decreased to two minute intervals. This is business as usual for one of the busiest railway stations in the UK. A large number of drivers throughout the morning had noticed strange but not unusual irregularities with the signal sequence. This was due to the signal in box A changing routes into different platforms causing the signal ahead to go back to red and the signals to the rear to react in sequence. In the rule book drivers were required to report a signal being more restrictive but due to this being a regular occurrence many ignored this and carried on as usual. This leads us on to the driver of a bazing stoke to London Waterloo Service Mr. McLimons. The 29th train booked to go along past Whiskey Foxtrot 138. As the train made its way past Earlsfield nothing out of the ordinary was noticed until the driver received an unexpected setback when signal Whiskey Foxtrot 138 had changed from green to red as the train was about to pass it. Not being able to stop in time the driver continued to next signal to report the incident. Driver McLimons left his cab to walk along to the signal telephone to contact the signal to find out the issues as per the rule book. McLimons had assumed that the signal that had changed back on him Whiskey Foxtrot 138 would stay red at his train occupied the section. An assumption that should have been right at a fully working signal. The 30th train, the 6.14 am Paul to Waterloo driven by a Mr. Rolls had been making progress towards London following driver McLimons train with nothing worth noting on the journey. His train approached and then passed Whiskey Foxtrot 138 at green at roughly 50mph. Driver Rolls thought nothing of it until the next thing he saw the rear of driver McLimons train by now disaster was inevitable. Driver Rolls applied the emergency brakes bringing the train's speed down to around 35mph as it impacted the rear of the train in front at 08.10 am. The front of the train had left the tracks and a third train running empty in the opposite direction collided with the Paul train. A fourth train following the Paul train managed to stop short in the rear. At the time of the impact driver McLimons was walking back to his train at which it moved forward several feet. He ran back to the signal telephone to inform the signaler who put all the signals under his control to red to stop all train movements. The impact of the front of the Paul train on the last carriage of the basing stoke train caused the last carriage to be thrown up above a concrete wall on the side of the cutting around 10ft high. It came to a rest lying on the embankment above the wall. The first two coaches of the Paul train had veered to the right where it had been struck by an empty train. The noise from the collision attracted the attention of nearby residents and workers around the north side of onesworth common. Many called 999 requesting emergency services. Waringly British rail contacted the emergency services after the first 999 calls at around 8.15am. This was due to the lengthy process of communication from driver to signal box to station supervisor to network control who finally contacted 999. The public had made their first call at around 8.13am. Pupils and teachers from the nearby manual school who were the first on the scene of the disaster helped the walking wounded. Access for the emergency services was limited. This was due to the majority of UK railways being fenced off from the public to prevent trespassers. The railway boundary has access points but these can sometimes be hard to find and require key access. The first three carriages of the Paul train had been severely damaged. The first carriage had totally collapsed. The second carriage, the buffet car, had been devastated on its left near side and the last car of driving McClimb's basing stoke train was also severely derailed and damaged. All of these factors further hindered the first responders. It was estimated that around 1500 people were aboard the Paul train creating an overwhelming situation. The trains in use at the time were of a very old design first generation British rail electric multiple unit and made use of slam manually opened and closed doors which can be opened at any time. Very different from the power control doors of today. Because of this many had already started to escape the wreck trains. The rescue effort would last the rest of the morning into the afternoon. The last casualty was taking the hospital at 1.04pm and the last body was removed at quarter to 4pm. Repair works in the area would take a lot longer as the damaged trains and infrastructure had to be removed before trains could run safely again and this doesn't include the investigation into how the disaster could happen. With 35 dead, 484 injured the big question looms. How? How can a tried and tested signalling system fail to do the one thing it was designed for and that was protect a train in its respective block? Whiskey Foxtrot 138 was obviously not working as intended which as it was a new installation hints that the engineering works were the root cause of the disaster. The replacement of the signal was part of a much wider program called WARS or the Waterloo Area Re-Signalling Scheme. This came about as by the 1970s and 1980s much of the 1930s wiring responsible for the safe operation of the railways had badly deteriorated. The program was undertaken over multiple weekends to improve the reliability of the signalling system. The wiring of the new signal was prepared and laid out over the week to be installed over the weekend. The signal and its wiring was completed on Sunday the 27th of November. It was common for the technicians who laid out the wiring to install it over the weekend leading to a seven day week and for Whiskey Foxtrot 138 this was no different with the book technician working his 13th consecutive seven day week. During the wiring installation the wires to the relay room in signal box A for the old signal needed to be removed as the new signal was wired to the track circuit block. It was deemed not ideal to fully remove the old wiring and instead it was opted by the technician to leave it in situ albeit disconnected. This is not unheard of as long as precautions such as disconnecting cutting back and taping off the stop the loose wire from coming into contact with any other terminals. The technician decided to keep the old wire still connected on one end and just disconnect and push back to one side the other end with the new wiring holding it out of place. Eventually this loose wire could work itself back to the terminal of the new signals wiring in the relay room causing the signal to not go to danger when the train occupied the block. No independent inspection by the technician's supervisor was undertaken meaning the shoddy work was not picked up upon. The signal would operate as intended until the weekend of the 11th of December where unrelated work was being undertaken in the relay room on the relay next to the new wiring. The work disturbed the uninsulated wire which had made its way back to contacting the relay causing the failure of signal Whiskey Foxtrot 138. The investigation by Lord Hidden found many contributors to the disaster including poor training, supervision, assessments, all of which were compounded by technical staff not properly understanding the ramifications of signalling failures. One of the largest legacies of the report into the disaster was the amount of hours the technician had worked. It would eventually prompt a change in working hours for people undertaking safety critical work to 12 hour maximum shifts, 12 hours minimum between shifts, a maximum of 72 hours per week and a maximum of 13 days in a row. If you've ever worked on the railway then these rules are hammered into you. The accident changed the culture in British rail and although no one was charged with manslaughter BR was charged with the health and safety at work act 1974 and had to fork out a £250,000 fine which doesn't seem like enough even for late 1980s and early 1990s money. This event would be partially responsible for the corporate manslaughter and corporate homicide act of 2007. The lessons learned from the accident would help shape the modern UK railway which would never be forgotten. At the time of recording this script I've just finished working on a Tokyo subway attack video so it's been a few weeks of railway stuff for me. I've really enjoyed working on it but more importantly though, have you enjoyed the rail based subjects and do you think I should cover more? Let me know in the comments below. Thanks for watching, I hope you enjoyed the video. This is a plain difficult production. All videos on the channel are creative commons attribution share alike licensed. Plain difficult videos are produced by me John in a sunny southeastern corner of London UK. Help the channel grow by liking commenting and subscribing. Check out my Twitter for all sorts of photos and odds and sods as well as hints on future videos. I've got Patreon and YouTube membership as well if you fancy supporting the channel financially and all that's left to say is thank you for watching. In 1977 a disaster would show the risks of heavy rainfall on an embankment dam resulting in structural failure. The resulting floodwater would cause nearly $3 million worth of damage and cost 39 lives. What was strange was that the structure was not new. Instead it was in its final arrangement for over 30 years which really shows that nothing is solid forever. Dam disasters are always scary incidents as seemingly unmovable imposing structures give the full sense of security for the vast water it holds back. This is why when a dam does fail it does so spectacularly. The Kelly Barnes Dam had the double surprise of being a pretty well established structure with varying designs being employed on the site ever since 1899 with failure occurring in 1977. Although the final iteration at the site was not as grand as say the Sayano Shyshenska due to it being a relatively simple earthen dam. Today's subject I'm going to rate it here 6 on the Plain Difficult Disaster Scale and here 4 on the Historical Legacy Scale as it is a relatively unknown failure in comparison to say the Yonk Disaster. The city of Tokoa, Georgia is a smallish municipality with a population today of around 8,000 people but the purpose of this subject we're going to start all the way back in time in the late 19th century. Tokoa was destined to have a hydroelectric plant and as such this necessitated a reservoir. In 1899 a rock crib dam was built by E.P. Simpson. It was located on the headwaters of the Tokoa Creek 1.7 miles northwest of the center of Tokoa, Stevens County, Georgia. The structure had a riveted steel penstock that extended from the dam to the powerhouse below. The waterfall to utilize the 280 foot head difference for power generation. The power plant went into operation the same year and was capable of a 200 kilowatt output. In the 1930s the Georgia Power Company purchased the local power distribution system passing the title of the dam, lake and power station to the Tokoa Falls Institute. The original dam height was increased in 1937 as power demands for more stable electricity increased. Between 1939 and 1940 the 38 high earthenfield dam called the Kelly Barnes dam was built on top of the original rock crib dam. Mr Kelly Barnes was the business manager for the Tokoa Falls Institute and that is how he got his name. Now I really need a dam named after me. The earth dam incorporated most of the old crib into its downstream tow. The structure was concave upstream filling a narrow portion to gorge formed by the Tokoa Creek. The impounded lake at normal pool elevation was approximately 40 acres holding back around 17 million cubic feet of water. An additional steel pipe was built to work as a low level spillway for the dam. During the works the power plant was also upgraded and masonry structures were built around this and the original penstock with valves controlling flow. An additional earthen spillway was added and this took the normal overflow of water. Post wall the dam was again heightened. Due to the works happening over the years no real design was really put on paper and this would prove difficult for investigators later on. The power plant was eventually shut down in 1957 leaving the dam and its lake for recreational use. After the dam was kind of left unattended with no official inspections or routine of maintenance. As such the main structure and its abutments became overgrown with bushes and trees. The foliage meant that the low-level spitway and penstock was visibly obstructed. During the early 1970s reports of continual seepage from the downstream slope of the dam near the points of the exit spillway pipe were made. At some point a large embankment slide had occurred on the downstream face around 1973. Neglected and not inspected the old earthen dam was arguably a disaster waiting to happen and that leads us onto 1977. During the period between November 2nd and November 5th around 3.2 inches of rainfall was experienced in the region. The water from the rain started to fill up the barn's reservoir bulging its banks. The rain got heavier during the evening of November 5th. At around 11.30pm volunteer workers went to the dam to inspect its condition from the rainfall and in the winter darkness all seemed well. Just a few hours later in the early hours of the 6th November 1977 at approximately 1.30am the Kelly barn's dam's main structure failed in the heavy rain. The failure released the water it held up down the Takoa creek on a collision course with the Takoa Falls Institute. One of the campus dorms would see the disaster's first victims as the tremendous power of the water swept through the area. In total 200 feet the dam had failed releasing at its peak flow 24,000 cubic feet per second washing away 9 houses, 18 house trailers, 2 college buildings and multiple vehicles. In total 39 would lose their lives during the event. Due to the time many residents were in bed asleep leaving little chance of reacting to the sudden flow of water. In addition to the human cost 5 houses and 5 college buildings were damaged. 2 bridges on Takoa Falls Drive and a culvert at County Farm Road were completely destroyed and Georgia's Route 77 which travelled through Takoa received considerable damage. The city itself saw some damage from the floodwater creating a local emergency. The water supply to the city was also damaged contaminating the drinking water for several days. A day after the disaster an investigation was ordered by Governor Busby appointing a task force on dam safety to look at the causes of the dam failure. The investigation was conducted by the US Geological Survey was concluded fairly quickly by December 1977 without a definitive reason for the failure. Instead several probable causes were settled upon. This wasn't so much the investigators thought as I mentioned earlier no proper plans or diagrams were made of the dam during its evolution leaving eyewitness accounts, historical photos and newspaper clippings to try and help build up a picture on the construction techniques used. Some of the causes for failure were linked with poor maintenance due to the dam's embankments being heavily vegetated with tree roots severely weakening the structure. This is likely as parts of the dam had slid from the original position in 1973 hinting that a similar situation could have been folded in 1977. The slide in 73 created tension cracks which could have further weakened the structure during the period of rainfall allowing seepage. Furthermore the long period of rain eroded away the downstream slope leading to a localised overtopping of the dam causing a chain reaction of more erosion and finally total structure failure. Another cited cause was that of the low level inlet pipe failing rupturing or becoming blocked leading to seepage and weakening of the structure from within. Although the exact causes are known one thing that is certain is that poor maintenance was the root cause as proper inspection and remediation work would have highlighted failure and stress points that needed to be addressed. What is most likely is that probably all of the highlighted causes contributed to the failure as the dam was weakened over a period of time. As a side note what is strange is that this disaster is another one I've covered on this channel under the Carter Administration. Regardless of the failure cause it is yet another reason why maintenance is very important be it your car or a dam. Thanks for watching I hope you enjoyed the video. This video is a plain difficult production all videos on the channel are created commons attribution share alike licensed. Plainly difficult videos are produced by me John in a sunny southeastern corner of London UK. Help the channel grow by liking commenting and subscribing. Check out my Twitter for all sorts of photos and odds and sods as well as hidden some future videos. I've got Patreon and YouTube membership as well so if you fancy supporting the channel financially you can there. Not what's left to say is thank you for watching. It's November 1955 and the world's first fast breeder reactor would experience a meltdown. The reactor designed and built to be a proof of concept would be successful however it would highlight the difficulties for such a reactor design type. The reactor a vital stepping stone in atomic history would be declared a national historic landmark in 1965. Reactor design is an evolution with several paths tracked along in the goal of creating more efficient and powerful units. Each path had a seed and one of these was the fast breeder reactor for EBR1. Okay I know I mixed up analogies there but you kind of get the idea. Almost every type of reactor has had a disaster or two and the fast reactor would be no exception. And as such I'm going to rate it here 5 on the painted plainly difficult disaster scale. But the EBR1 as a whole will get an 8 on the historical legacy scale because it is so important they turned it into a museum with other reactors parked outside. Our story starts in the late 1940s and a concept for a reactor that would create more fuel than it used. Walters in a Canadian American nuclear physicist on the urging on Orico Fermi set out to prove the theory with a small test unit. The reactor would employ a liquid metal coolant in the form of NAK which was a poor moderator but transferred heat efficiently ideal for the concept. You see a breeder reactor doesn't want a moderator to slow down the neutrons from fission instead using a blanket of fertile material to create more fuel. Construction began in 1949 at the Idaho National Laboratory in Idaho and it is around here on the map. The reactor had 217 fuel rods and 138 internal blanket rods used for breeding fuel. The unit had 8 safety and 4 control rods with the ability to scram shutting down the reactor placed around the outer section of the core. These were moved in and out by gears and used a magnet de-energizing for scram. The core was surrounded by graphite separated from the reactor by an air gap. Criticality was achieved in August 1951 with full power operation at 1.1 megawatts of thermal energy being reached on December 19th 1951. A day later the world's first electricity generated from nuclear power was achieved by powering four light bulbs via the plant's turbine. The next day the experiment was repeated and generated enough electricity to power the whole EBR1 facility. Although great this was it was also a bit of a sideline to the reactor's main goal which was breeding. An indication a year later would be seen to prove the scientists theory. In early 1953 laboratory analysis showed that EBR1 was creating more than one new atom of nuclear fuel for each atom burned. Fully powered up the reactor could create 1.2 megawatts of thermal energy that could be converted into 200 kilowatts of electrical energy which funnily enough was roughly the same produced by the power station at the Kelly Barnes Dam. In 1955 operators decided to test out the EBR1 to investigate issues highlighted during previous operations. What confused the scientists was that the reactor showed instabilities when coolant was at different flow rates. The test would involve the reactor at high power, intermediate power and very low power with varying levels of coolant rate. Basically seeing how the reactor well reacts to low coolant situations. To run the experiment the reactor would achieve criticality and gradually increasing power without coolant. We can probably see where this will end up. On November 29th 1955 operators at the EBR1 were about to undertake the test. The reactor was made critical at an initial power output of around 11 watts. The control rods were used to manage the power of the reactor up to 50 watts not long after 500 watts was being produced by the unit. As the power continued to rise the fuel rods temperature also began to rise more than normal. The power continued to increase and a shutdown signal was sent to the control rods to scram the core 500 seconds post initial power increase. For around two seconds the power level had gone off the maximum end of the instrumentation. Even though the signal had been sent by the control system the reactor power carried on increasing. Fearing the ramifications of this the operators manually activated a scram on the core. The reactor power finally dropped off eventually going sub-critical. From the control room the reactor seemed okay the coolant pumps were started up to try and dissipate the heat throughout the core. What the operators didn't know was that the core fuel had reached a temperature of 2170 degrees centigrade and have reached a power of 9 megawatts during the peak of the meltdown. In total between 40 and 50 percent of the fuel had been damaged during the excursion completely knackering the fuel loading of the EBR1 reactor. Not long after the NAK reactivity level alarm went off hinting at fuel melting and shortly after that health physics instruments indicated that there was air contamination in the building. Operators were evacuated from the building until proper surveys could be undertaken. Later surveys showed that low level radioactive gaseous had been released with minor thyroid gland activation in a few of the operating personnel. Post incident an attempt was made to remove the blanket and core elements from the reactor. Novel signs of fuel damage were found during initial removal of the blanket allowing extraction via the conventional way. When attempting to remove the rods containing fuel from the outer rows of the core considerable force was required by the technicians and damage to the jackets was observed and it only got worse from there. Due to the now observable damage it was decided that the whole core would be removed from the top of the reactor for further disassembly. Due to the extreme levels of radioactivity from the damaged core a cave was built around the unit on top of the reactor structure.  It was thought that this wall was thick enough to allow limited time for personnel to remove the fuel. When the cave was completed and necessary tools had been constructed the NAK coolant was sucked out of the core and proper disassembly began. The molten core alloy was found to have entered into the coolant channels and to have solidified into a mass surrounding the fuel section. All of this was covered in coolant. Sores had to be used to separate the fuel elements and this proved to be hard going work. After several small NAK fires resulting from removal of the outer fuel elements it was decided to stop further disassembly operations at the Idaho site and ship the core to the Le Mans site. A new cave containing a lower oxygen environment was built capable of containing 10,000 curies of one MEV gamma activity for final disassembly of the remaining fuel. To transport the damaged fuel to a hot cell a lead cask was used. The meltdown at the EBR-1 wasn't considered an accident as fuel melting was a known risk for the experiment and the core loading was nearly the end of its life expectancy. The meltdown did not lead to the end of the EBR-1 as a new fuel loading was installed into the unit. On the 22nd of November 1962 EBR-1 became the first reactor to produce electricity from a plutonium core but after 12 years of operation the unit was shut down in 1963. Lyndon B Johnson in 1965 listed the reactor as a national landmark virtually guaranteeing its place in history which is a museum to this day a definite place on my to visit list. Thanks for watching I hope you enjoyed the video this is a plainly difficult production all videos on the channel are creative commons attribution share alike licensed plain difficult videos are produced by me John in a sunny southeastern corner of London UK help the channel grow by liking commenting and subscribing also check out my twitter for all sorts of photos and odds and sods as well as hints on future videos I've got patreon and youtube membership as well so if you fancy check them out all that's left to say is thank you for watching a town that was once originally the dream of a nice summer resort would take a downward spiral to a low income suburb and ultimately a contaminated and abandoned lesson on waste disposal if you were to travel to this town today not much would tell you of the disaster that befell its residents but the story involves a lot of dioxin contaminated waste being sprayed on the roads of Times Beach Missouri. Times Beach has a strange story that was an odd side effect of the Vietnam War many thousands of miles from the battlefield in Missouri an unknowing contractor would spread deadly darks and contaminated oil as part of a dust reduction service for dirt tracks now I know this is an odd picture I'm painting but as I said Times Beach is a strange story and as such I'm going to rate it here seven on my patented plain difficult disaster scale and also seven on my historical legacy scale due to the seemingly obvious lessons that had to be learned our story starts with a newspaper advert in an effort that reminds me of London's metro land during the early 20th century a purchase of a plot at Times Beach came with a six month subscription of the st. Louis Times newspaper okay okay uh the comparison is a bit of a reach but it is similar in a sense that a company would sell you a lifestyle to further an ulterior company goal in Metroland's case it was to pay for new railways but in Times Beach's case it was an effort to prolong the newspaper's longevity the location of Times Beach was a 480 acre area around 17 miles west of st. Louis on the I-44 highway next to the Merrimack river and had previously been a flood plain used for farming because of one 20 feet by 100 feet lot in Times Beach was $67.50 but in reality to build anything worth habitation a couple of plots were needed the community was doomed from the start as the area was prone to flooding as such the properties were built on stilts and because you had to build a summer house yourself or get someone else to do it wasn't the uniform affair of modern day holiday results the community not long after its conception would have to bear the brunt like many other communities throughout the world of the great depression in the late 1920s understandably summer houses weren't necessarily a necessity during a period of economic downturn so those that could sold up however many didn't and instead took to living by the river to ride out the financial storm the community would once again get a kick in the stomach when during the second world war gasoline shortages would discourage many from visiting their holiday homes leading to more properties being sold off for permanent residency by the 1950s the area saw redevelopment with many of the summer houses rebuilt into low-income residential use the properties were not built on stilts as flooding had become a thing of the past the roads throughout the community were unmade dirt arrangements and this caused a pretty large nuisance for the residents and that is dust as a car trundles along a dirt road it unsurprisingly in dry weather kicks up dust into the air not great if you have clothing out on the line or are just generally outside and this problem had a solution that is probably tarmacking the road and maintaining it which is what didn't happen at times beach and instead old engine oil was used to suppress the dust kick up to be fair to the cash trap city paving the roads wasn't exactly affordable used oil is a cost effective solution but it doesn't exactly last forever and needs reapplication which is why someone can make some money out of servicing an area and this brings on waste hauler Russell Bliss Bliss's solution was to spray the roads around the community with waste oil at a bargain price of six cents per gallon and he would begin a job in 1972 but let's pause here because you might be thinking how has this got to do anything with the Vietnam war around 230 miles down the road in the rona Missouri a company called Hoffman Taft opened up a chemical production facility in 1949 the site was used to produce several different products including prist and aero fuel additive panterplex and animal feed fortifier and a more well-known chemical agent orange agent orange was an equal mixture of two phenoxy herbicides two four dichloro phenoxy acetic acid and two four five trichloro phenoxy acetic acid which contained traces of the dark sin two three seven eight tetrachloro dibenzyl p dioxin a deadly carcinogen the agent was used as a defoliant in an effort to try and deny the vietcong competence food and concealment often taffs started to experience financial difficulties towards the end of the 1960s and started to lease out some of its rona facility to the north eastern pharmaceuticals and chemicals company never co use the site to produce hexachloro theme an antibacterial agent used in soap toothpaste and disinfectants dioxin as we found out at Cefesso is highly toxic and can cause cancer reproductive and developmental problems damaged to the immune system and hormone interference the contaminants started to mount up on site a problem was created which was how to get rid of the dioxin the proper method was that of incineration but the rona site didn't have an incinerator meaning nepaco had to pay for disposal and this isn't cheap looking for a cheap alternative nepaco contracted independent petrochemical corporation to remove the contaminants a price was settled upon but ipc didn't have the experience in disposing of dioxin contaminated bottoms so the company subcontracted the work to rustle bliss the waste oil hauler that had a good thing going spraying dirt tracks bliss claimed later on that he wasn't aware of the toxic contamination or the materials he was paid to dispose of bliss took the dioxin contaminants to his facility and mixed it with the used oil for roadway spraying operations bliss also had a side business in training and breeding horses he found that his oil spray worked well in horse arenas and as such he had treated his own land with the oil this does make me think that he was unaware of the deadly chemicals he was using as why would you spray your own land bliss's oil spraying service impressed some of his horse breeding buddies as the mixture kept down a dust for a few months during may 1971 bliss's services were employed at a number of horse stables most notably the Shenadara stable located near Moscow mills Missouri what was odd was that bliss's oil was unusually thick and had a strange odor and many animals exposed to the treated soil would die including birds and eventually the prized equestrian livestock a month later in 1971 bliss was employed to spray at another stables near Jefferson city Missouri not long after a child developed chloracne and some of the horses became ill a third stables was also done around the same time all three sites suspecting bliss's operations ended up removing the topsoil around august the cdc got involved and took samples of the affected area but the results were inconclusive however they would conduct more tests finding trichlorofenol which can contain dioxin in the meantime bliss continued to spray waste oil anywhere he would get paid for and this leads us back to times beach between 1972 and 1976 bliss had been contracted to spray times beach is 16 odd miles unknowingly the sum 2000 residents would become exposed to the dioxin contaminated oil just like in 1971 times beach received a strange odor and saw birds dying of vicinity after bliss has sprayed his oil in total including times beach around 40 sites have been contracted by bliss to do dust treatment in Missouri whilst always was going on the cdc were trying to find the source to the mysterious illnesses reported in animals and local residents around Missouri the cdc searched for companies that had manufactured trichlorofenol and only one place was found nepaco in Verona now in 1972 nepaco had gone out of business due to the fda issue ban that limited the use of hexachlorofen which is a source of the byproduct dioxin the facility in Verona became fully under the control of syntax agribusiness leaving behind 4300 gallons of dark zinc contaminated bottoms in 1974 dark zinc poisoning was tied to the mysterious illnesses in the stables after a more in-depth sampling was ordered after the detection of trichlorofenol there was one link between all the contaminated sites and that was bliss but the investigators had to find a link between bliss and nepaco the closure of nepaco would reveal a deadly secret in 1979 which would finally give the cdc and the epa the missing link into the source of the contamination an ex-employee had blown the whistle on their old employer informing authorities about seven miles away from Verona dark zinc contaminated material had been illegally dumped in a farm the epa discovered 90 rusty seeping barrels buried at the farm revealing large quantities of dark zinc the dump site showed that nepaco wasn't adverse to just using anywhere or anyone for dumping bliss was questioned and claimed no knowledge of dark zinc but he did admit to being hired by ipc to dispose of the oils from the nepaco site the link was finally proven times beach wouldn't know the cause of the sickness until 1982 some 10 years after the first application of bliss's waste oil the information that times beach was one of the many contaminated sites from the dark zinc from Verona was leaked to the residents and the epa confirmed their suspicions but still needed to conduct more tests dark zinc was confirmed at times beach but things were going to get a whole lot worse for the town in early december 1982 the epa had conducted some initial testing but the Merrimack river had other ideas flooding almost the entire town and the area was inundated with backwaters from the river most of the residents had fled the town but if it wasn't bad enough the water had spread the dark zinc contaminated topsoil to almost every corner of the community by the time the floodwaters have receded the results were in from the epa's testing and dark zinc was found to be a hundred times that of a safe level the contamination was recorded at 0.3 parts per million by mid december some of the residents of times beach have returned to begin the drying and rehabilitation process but that wouldn't last for long on the 23rd of december 1982 the epa released the infamous christmas message if you're in town it is advisable that you leave and if you're out of town do not go back the message was essentially the death warrant for the community and on the 7th of january 1983 president ronald reagan created the times beach dark zinc task force on the 22nd of february 1983 the epa announced that the federal government would front 33 million of the estimated 36.7 million costs to buy out the residential properties and businesses of times beach leaving just under four million to be picked up by the state the site was placed on the superfund national priorities list two years later pretty much all of the residents of times beach had been bought out and relocated and now the abandoned town became the perfect location for the much needed incinerator to dispose of missouri's dioxin which would finally be completed in 1997 about 265 000 pounds of contaminated soil and debris from times beach and 28 other sites in missouri was burned after the completion of the incinerator activities and cleanup of the site the abandoned community was taken off the superfund national priorities list in 2001 the site today has been redeveloped into a state park called the route 66 park and there is also a visitor center on the site there's little much left to tell you that once a small community resided here as you can see here in the satellite photos that the town is pretty much gone not surprisingly nepaco ipc and bliss were hit with multiple lawsuits for the contamination all over missouri due to the error in which bliss operated he was not required to and did not record the sources of his waste operations and all throughout the event he claimed no knowledge of the dioxin contaminants but we will never know for sure nepaco and ipc had to pay out a lot of money as many lawsuits were brought against them and they had no excuse for not telling anyone what the oil contained syntex agribusiness the company that took over the verona site was fined 200 million dollars for their part in the disaster thanks for watching i hope you enjoyed the video this video is a plain difficult production all videos on the channel are creative commons share attribution like a licensed plain difficult videos are produced by me john in a sunny south eastern corner of london uk help the channel grow by liking commenting and subscribing check out my twitter for all sorts of photos and lots of sods as well as hints on future videos i've got patreon and youtube membership as well if you fancy supporting the channel financially all that's left to say is thank you for watching one of the series of dams in buffalo creek west virginia would fail causing a catastrophic domino effect releasing some 130 million gallons of black water down onto the residents some 250 feet below the disaster would cause a 10 to 20 feet high tidal wave washing down the creek and valley causing a death and destruction trail of 15 miles over a three hour period not only a local tragedy but the event would highlight the dangers of such storage operations and the coal industry as a whole the disaster would leave a cost of 50 million dollars in property damage and 15 million dollars in highway damage but more importantly 125 were killed and nearly 5000 made homeless today we look at the buffalo creek dam failure and subsequent flood on the 26th of february 1972 and as such i'm going to rate it here eight on the patented plain difficult disaster scale buffalo creek valley is in the southwestern corner of west virginia 40 miles south of charleston the area has been used for mining activities all the way back to 1900 development of the coal industry in the area increased when in 1914 a railway spur was built by 1920 the creek was peppered with small mining camps that would eventually develop into small communities once the land was sold off to private residents many of the people lived on the narrow flat flood plain of around 400 feet wide along the creek the hilly and narrow valleys of the area limited the overall population and because of this logan county as a whole only had a peak population in 1950 of around 77 000 in 1945 the lorado mining company opened mine number five and began activities in one of the forks off the creek named middle fork the waste from the on-site coal preparation plant was sent to the mouth of the middle fork building a large waste bank called bank one across the hollow now a preparation plant washes coal of soil and rock and crushes it into graded sized trunks the waste is largely coal contaminated water and soil in 1959 the company began pumping wastewater into the hollow behind the waste bank one to settle out solids from spent wash water the intention was to build a reservoir but the bank was too porous leading to water leaking out this problem was later solved in the 1960s when much finer waste from a local strip mine was added to the bank which did hold back much more water the mine was taken over by buffalo mining company in 1964 the water was decanted from the reservoir into a smaller clearwater pond for recycling for use in further preparation of coal by 1966 waste bank one went 1500 feet down the middle fork and was 200 feet high at the face of the buffalo creek a disaster in wales u k would cast doubt upon the bank's stability which would result in the survey 1966 as a side note abba fan is most certainly on my list of disasters to cover the year after inspection the bank grew in height by another 50 feet as more and more waste was dumped on site going into 1967 a new dam behind the clear pond was created from waste 600 feet upstream from the original bank by the end of the year the dam was extended allowing a 20 feet deep pool to form by 1969 this dam and pool was not enough and this necessitated the construction of a third dam this new dam number three was 600 feet upstream and was around 60 feet above the second dam in 1970 the pitstone coal company took over the operations on the site after extensive surveys of the buffalo mining company's properties it was given a thumbs up as safe by the new owners worryingly in 1971 pitstone was cited for over 5000 safety violations at its mines nationally by early 1972 dam three had extended 465 feet across the fork along its front downstream crest about 800 000 tons of coal waste had been dumped to form the dam and it was able to impound a pool of around 30 feet deep most of the dams in this area were only intended to hold water from rainfall or high levels of wastewater for shortish periods of time however for dam three the pond was often full to the brim during the construction of the dam trees and vegetation were not removed and instead just covered over with coal waste forming part of the upstream and downstream faces not only that but the waste had a foundation of sludge roughly around 50 feet thick the comparison dam two had a sludge base of 100 feet thick no segregation layering or zoning of the material used to build dam number three was undertaken to obtain maximum stability no type of spearway was built into the design instead relying on excess water seepage through the dam augmented by an overflow pipe another dam number four built further up the fork was around 200 feet long and had a crest of 40 feet over its highest side this construction did have a spillway however this brings us on to the 22nd of February 1972 and a clean bit of health of dam number three from the federal coal mine inspector but not more than four days later the structure would experience a total failure in the following days the region would experience rain showers worrying about the increase in dam three's pool water level company strip mine superintendent Jack Kent checked the levels with a measuring stick at the lowest portion of the dam on the 24th of February he discovered that the water stood just five feet below the dam's crest the rains continued and the following day the level increased by one to two inches per hour at 4 30 a.m on the 26th Kent found his measuring stick almost covered with the water just 12 inches below the lowest part of the dam's crest more worryingly the face of the dam was now oozing moisture at 5 30 a.m warnings were sent out to the local population by the sheriff's office half an hour later a team led by Kent went to the dam to attempt to create a relief pipe to try to reduce the water level the water from this pipe flowed over dam two but would prove to be too little too late leading up to 8 a.m the dam began to subside and slump allowing water to top over the crest at 8 o 5 a.m dam number three failed washing dams number one and two away the wall of water flooded the burning refuse dump causing an explosion the effulgence carried on down the fork to the valley of buffalo creek the flow of water further eroded the remains of dam number three increasing the speed of the release drainage of the pool continued until around 8 30 a.m around six million cubic feet of coal waste and other debris was carried downstream with around 90 percent of it escaping the middle fork with some reaching a distance of up to two miles the 10 to 20 foot high flood wave traveled along the 15 mile buffalo creek valley at an average speed of around five miles per hour finally reaching the town of man at around 11 a.m the disaster destroyed or damaged homes in saunders padi lorado londale stowe latrobe robinette amherstale beko vanco brayholm acoville crown and kissler in the immediate aftermath the disaster rescue operations and accurate reporting of the dead and missing were made difficult as access to the area by road had been disrupted with bridges destroyed and rail lines blocked or flooded 125 were killed and 1121 were injured and over 500 homes were uninhabitable leaving between 4 and 5 000 people homeless or without adequate shelter man high school was used as a temporary refugee location for buffalo creek survivors republican governor arch more announced the creation of a commission of inquiry to investigate the flood it was formed of nine members most of whom were sympathetic to the coal industry in response a citizens commission was set up to create an independent review of the disaster also the senate subcommittee on labour started an investigation in late may 1972 using experts from the us army corps of engineers who built a scale model of the valley including locations of the failed dams with so much destruction and death and an estimated damage cost in excess of 65 million dollars how did dam number three fail so catastrophically well much like the kelly barns dam which would fail five years later the banks in the middle fork didn't have an official design meaning construction was not to a uniform standard and was not properly inspected and maintained the united states department of the interior report highlighted five key causes for the failure of dam number three the first was that the dam was not built to withstand the amount of water in the pool this was due to the construction basically being a pile of dumped coal waste no spillway or other adequate water level controls were built into the dam on top of that there was no way for removing water once it had entered the pool behind the dam the small piping still during the evolution of the dam was insufficient and was too high to really make a difference third the sludge on which the dam was placed was inadequate as the foundation led to seepage and subsidence across the main structure fourth the whip for the dam was cited as an issue as it impeded any water through the bank leading to a large of an intended amount of water being held back this was because the dam was meant to be for water recycling instead of permanent retention and finally the fifth cause was the inadequate quality and grading of construction material which consisted of coal waste including fine coal shale clay and mine rubbish furthermore the pipe that had been placed inside the dam the one that was too high to make any difference also had a double failure of weakening the already poor material choice the ad hoc committee focused on improving legislation recommending all dams or impoundments constructed of coal refuse to be properly zoned for control of seepage rates requiring all dams or impoundments higher than 10 feet to be instrumented and monitored on a regular and frequent basis and requiring all dams or impoundments to have a full proof decant systems and or spillways designed by and constructed under the direction of a registered professional engineer with a completion in the design and construction of dams the citizens investigation was far more damning of the buffalo mining company and its later owners the pitstone coal group stating in its conclusions the company was grossly negligent in constructing and operating the refuse down on its property the company violated state and federal law since the dam was never approved for proper design and maintenance and the company's first concern has been to increase its profits by using the same refuse dam to dispose of clarified wastewater and store water needless to say the mining company would have a number of lawsuits to answer to in attempt to absolve itself of any blame pitstone coal put out a press release not long after the flood stating that the disaster was an act of god and the dam was incapable of holding the water god poured into it around 600 survivors of the flood sued pitstone coal company seeking 64 million dollars a settlement was later reached in june 1974 at a fraction of the cost of 13.4 million dollars roughly 82 million dollars in today's money another lawsuit brought on behalf of the child survivors which was again settled in june 74 for 4.8 million around 29 million today the state of west virginia also took pitstone to court for a hundred million dollar lawsuit to cover disaster and relief damages but governor arch a more settled the case for a measly one million dollars three days before leaving office in 1977 more had been accused during his time as governor of corruption and this settlement didn't do much to disprove it this left a bill around nine million dollars to be picked up by the state of west virginia to pay the us army core of engineers for recovery operations and what seems to be a very foul tasting trend with disasters of this type no criminal charges were brought against the company for their negligence we know the lessons were never properly learned from buffalo creek as the kingston fly ash spill would happen some 36 years later and there are still many coal impoundments that offer risk to the communities that live nearby thanks for watching i ho