 It is a March morning, and residents in the East Harlem area of Manhattan, New York are going about their normal business. Trains passed East 116 and 117th Street on the Metro North Railroad. To anyone in the buildings at Overlook Park Avenue, not much out of the ordinary can be seen. Until approximately 9.30 in the morning and an explosion consumes two multi-use buildings. In a blink of an eye, the calm activity of the city is destroyed, confusion and chaos ensues. But what caused the explosion? Was it a terrorist attack, industrial disaster, freak accident? Well, that's what we will find out in today's episode. My name is John and welcome to Plainly Difficult. Background Well, I'm not going to go back too far as New York's history is rich and diverse, that stretches back several hundred years. But I'll try and fill you in into what's relevant for our story. We'll go back to the late 1800s Victorian New York. As a side note here, do we call this period of American history Victorian? I'm guessing not. I suppose you'd call it by… the Grantean period? Well, all modern cities needed reliable facilities, such as freshwater and sewage. Just asked the residents of London's Soho 150 or so years ago. There was a project to give New York a sewer system. It actually started in 1848 and much like in London, was spurred on by a number of deadly cholera outbreaks. But I digress. In the early 1870s Park Avenue was dug up in a project to add reliable sewage to the area. Park Avenue, by the way, is around here on a New York map. A brick lined oval sewer was constructed roughly in 1873. It was 15 feet below the street and was 32 inches wide by 48 inches high. Just over 10 years later, the area was dug up once again for the addition of services to the residents on Park Avenue. This was to hook up gas lines in 1887. An 8-inch wide cast iron gas pipe which was installed roughly around the same time. A 12-inch cast iron freshwater line was also added. These were about 4-5 feet below the roadway and were separated by 2 inches apart from one another. Now it goes without saying that these amenities are somewhat difficult to maintain due to being buried several feet below ground. In the early 2000s, the city started to get some odd reports of the pavement outside building 1646 Park Avenue sinking into the ground. These reports resulted in the road being patched up. In 2004, a report of a sewer undermining condition was made, which would require further investigation. In 2006, it was discovered that the brick sewer had been breached between 116th and 117th East Street, in the same area that the pavement issues had been reported. Due to the difficulties of repairing, the city decided to monitor the situation. Three more reports of the pavement sinking were received by the New York Department of Environmental Protection and the New York Department of Transportation in 2007, 2009 and 2010. Needless to say, this was a bit of a known issue for the pavement and road outside building 1644 and 1646. In 2011, the road portion of Park Avenue outside building 1644 and 1646 found itself dug up once again. There was a new building being constructed at 1642 and the four-story high residential building needed a new gas supply. This is where Consolidated Edison comes into our story. They are a company that are in charge of the utility supply in New York City. As such, when 1642 needed to be hooked up to the gas main, Con Edison were there with the diggers. Usually, when old cast iron pipes are exposed, they are replaced with a more modern HDPE type. The size of the gas pipe remained at 8 inches wide. To get the gas from the main to the new building, a 2-inch diameter HDPE gas service line and a fusion welded plastic service T were connected. Around the same time, mains water and sewage were connected to the new building. Later on in 2011, the damaged sewer was inspected once again and was seen to not have to have continued to degrade at least that much. And thus Park Avenue had a new building, some new gas lines, tranquility and harmony. Well, if you believe that, you're watching the wrong YouTube channel. The Disaster. It is 9.06 in the morning of the 12th of March 2014 and Consolidated Edison's customer helpline is about to receive a phone call. Well, that's what it's there for after all. The call is from a resident in the building at 1652 Park Avenue and the phone call is to report the smell of natural gas. This took roughly 6 minutes to complete, concluding with the advice to evacuate the building. The Con Edison rep advised that someone will be there within 45 minutes or so. At 9.12 in the morning, the emergency response team at Con Edison were informed of the reported leak. Several telephone conversations followed between the customer service rep, the emergency department and the New York fire department. The last of the calls happened at 9.19, but in just 11 minutes disaster would strike. Meanwhile at 9 o'clock in the morning, residents of building 1644 and 1646 were oblivious to the unfolding emergency. At roughly 9.30, buildings 1644 and 1646 exploded, blowing out the brick facades of the structures, and debris was thrown out into the road. Shortly after the two buildings collapsed into their own footprint, the mixed residential and commercial spaces were now just a pile of flaming rubble. Almost immediately the first 911 calls came in and three minutes after the first fire engines were on the scene. At roughly 9.39 in the morning, the dispatched Con Edison engineer arrived to what could be described as a bad day at the office. Anyone who could began assisting the injured? Windows in nearby buildings were shattered and debris was thrown up to a block away. Some had even landed on the elevated section of the Metro North Railroad. This necessitated the line being shut down until the late afternoon. Around 100 New York police department officers were on the scene from 10am and helped to create an exclusion zone around the still burning buildings. Strangely at 1.30pm a hole started to appear outside the destroyed buildings in the roadway. The explosion had damaged the water main and it had eroded the ground around it. A couple of hours later, a smaller explosion ignited in the hole. This would later require digging out and filling with steel plates and gravel. The residual fires were burned for another six days, hindering recovery work, but finally extinguished on the 18th of March. In total, eight people had lost their lives, with another 50 being injured. Understandably explosions in US cities aren't the most common event, so needless to say the cause had to be found out. Spoiler alert, it had something to do with the mysterious case of the sinking road. Strangely, well at least I think it is, the investigation came under the purview of the National Transport Safety Board. It's actually quite handy as NTSB reports are usually easy to find and make pretty good source material for one of my videos, but they weren't the only to investigate. Unsurprisingly the question of the explosion source had to be found, and this came from Con Edison as well. It's not too difficult to put together reports of gas leaks followed by a big boom after all. The New York Fire Department concluded upon its survey of the wreckage that the explosion had originated from building 1644, inside the first two floors, which were occupied by a church. Con Edison conducted pressure tests on the pipeline either side of the destroyed buildings, and only minor leaks were detected. This pointed at one probable failure point. The welded T-joint from the gas main to building 1642. The joint was investigated and it was found to be faulty, likely due to improper preparation before welding. But how did the T-joint fail, because clearly it wasn't leaking after immediate installation, even though it was faulty. Well the NTSB would conclude that the instances of the ground sinking outside 1644 and 1646 was actually being caused by that damaged sewer, which washed away the soil supporting the gas main line. This in turn allowed the main line to sag, which put extra stress on that joint. The joint then fractured and allowed gas to seep next door, where it was just a matter of time before the inevitable would happen. So the blame game had to stop at the feet of Con Edison and the city, who was in charge of the sewage. And also as well, the New York State Public Service Commission. The city would refute the NTSB findings and turn on Con Edison, which in 2017 resulted in a settlement from Con Edison to New York City, for a grand sum of $153 million. With reportedly about $25 million going to the victims. Now I'm going to rate this disaster as negligence, as the leaking sewer was known about for the best part of a decade and just left. And also as well as the poor gas main T joint. I'm also going to rate it a 4 on my legacy scale. This is a plain difficult production. All videos on the channel are creative commons attribution, share a lot licensed. Plain difficult videos are produced by me, John, in a currently wet and windy corner of southern London, UK. If you want to find out hints on future videos, you can by checking out my Twitter. I also have Instagram as well, which I put up random photographs. If you are enjoying this outro song, then feel free to go over to my second channel, made by John, where you can listen to it in full. And all that's left to say is, thank you for watching and music man, play us out please.