Intro

East Harlem explosion It is a March morning and residents in the east Harlem area of Manhattan, New York are going about their normal business. Trains pass east 116 and 117th street on the metro north railroad, to anyone in the buildings that overlook park avenue not much out of the ordinary could be seen. Until at approximately 09:30 an explosion consumes two multi use buildings. In a blink of an eye the calm activity of a city is destroyed, confusion and chaos ensues. 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.

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 to what’s relevant for our story. We will go back to the late 1800s Victorian New York however, side note here do we call this period in American history Victorian, I’m guessing not... I suppose you’d call it by the president's name?. Grantian period?? Well all modern cities need reliable facilities, such as fresh water and sewage, just ask the residents of London’s Soho a hundred and 50 or so years ago for the other option. The project to give New York a sewer system actually started in 1848, and much like in London was spurred on by a number of deadly cholera outbreaks. I digress, in the early 1870s park Avenue was dug up, in a project to add reliable sewage to the area. Park avenue is around here on a map. A brick lined oval sewer was constructed roughly in 1873, it is 15 feet below the street and is 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 was installed, roughly around the same time a 12 inch cast iron fresh water line was also added. These were 5 and 4 feet below the roadway and were 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 getting 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 this the city decided to monitor the situation. 3 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 buildings 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 4 story high residential building needed a new gas supply. This is where consolidated Edison comes into our story, they are the 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 where there with the diggers. Usually when old cast iron pipes are exposed they are replaced with a more modern hdpe type, the size for the gas remaining 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 tee 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 again and seen to not have continued to degrade 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.

Disaster

It is 0906 on the morning of the 12th March 2013, 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, to report a smell of natural gas. This call took roughly 6 minutes to complete, concluding with the advice to evacuate the building. The con Edison rep also advised that someone would be there within 45 minutes. At 09:12 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 City fire department. The last of the calls happened at 09:19 but in just 11 minutes disaster would strike. Meanwhile at 0900 residents of building 1644 and 1646 were oblivious to the unfolding emergency. At roughly 0930 buildings 1644 and 1646 exploded blowing out the brick facades of the structures, 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 three minutes after the first fire engines were on the scene. At roughly 0939 the dispatched con Edison engineer arrived on what could be described as a bad day at the office. Anyone who could began assisting the injured, Windows in nearby buildings was shattered and debris had been 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 nypd officers were on scene from 10 am and helped create an exclusion zone around the still burning buildings. Strangely around 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 water was shut off at 5 20pm. The residual fires would burn for another 6 days, hindering recovery work, finally being extinguished on the 18th March. In total 8 people lost their lives with another 50 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. The investigation.

Investigation

Strangely well 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 ones to investigate, unsurprisingly the question of the explosion source had to be found first, 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. The nyfd 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 main gas to the building. 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 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 mainline. This Inturn allowed the main to sag, which put extra stress on the 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 incharge of the sewage. As well as 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 of $153 million. With reportedly 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. As well as the poor gas main t. I’m going to rate it a 4 on my legacy scale. https://www.ntsb.gov/investigations/AccidentReports/Reports/PAR1501.pdf