Explosion de Beyrouth : le désastre reconstitué

shortly after 6 p.m. on August 4, an

explosion

ripped through Beirut's port, killing more than 200 people, injuring more than 6,500, and destroying much of the city. Ms. Mass invited forensic architecture to examine open source information, including videos, photographs and documents to provide a timeline and an accurate 3D model to help investigate the events of August 4. The model is available through this link. The first photo of the burning warehouse was posted to Twitter at 5:54 p.m. m., we carefully geolocate this photograph by identifying the key buildings and calculate the cone of view of the camera in this image, we identify the location of the source of the smoke column in the northeast corner of warehouse 12.

The smoke columns are continuously transformed and have a unique shape at each moment, we model the column at this crucial stage to help synchronize other videos without timestamp. A video recorded at around the same time from one of the balconies of the residential tower building clearly shows the same fire source on the same side of the warehouse, the shape of the smoke plume and the heat source. suggests the fire had developed, another video from 5.58pm from nearby St George's Hospital provides 10 minutes of uninterrupted footage of the warehouse, within two minutes the smoke thickens and its color changes to a darker tone, according to Gareth Collett, a UN explosives analyst.

We consulted this suggests that the material being burned inside the warehouse has changed. At 6:07 pm a new source of intense heat appears on the other northwest side of the warehouse, followed by a different, larger column. The sparks that follow suggest the presence of small explosive charges. like fireworks 35 seconds later, at 6:08 pm, a large spherical column appears above the center of the warehouse, according to the explosives analyst, the symmetrical shape of the sphere suggests that it is a single point

explosion

originating from a particular location within the warehouse and it is possible that only half of the 2,750 bags of ammonium nitrate stored inside detonated.

We use the shape of the two columns of these explosions as metadata to synchronize the remaining images. This video taken from further back provides an uninterrupted view of the events that followed during the lapse. Within nine seconds, the spherical column was projected into the atmosphere with several tons of thick particles in the air and a red column 755 meters high rose above the warehouse. Thus, we have identified four types of smoke plumes emanating from different parts of the warehouse within the space. of these 14 minutes the first column at 5 54 pm emanates from the northeast corner of the warehouse the second column at 6 pm comes from the same point of origin but has a darker color the third column appears on the northwest side of the warehouse at 607 pm The final column develops from a spherical explosion located in the center of the warehouse at 608 pm.

Each of these columns of smoke with its distinct shape and color provides indications about the arrangement of the goods in the warehouse, the way the fire developed and the arrangement of what was stored inside. Close examination helps to understand the evolution of the fire inside the warehouse. Early images show smoke billowing from every opening, including windows and roof vents. From this point, around 5:56 p.m. m., the temperature inside the warehouse began to rise rapidly. Smoke is visible as it changes color to a darker tone in this footage. From the east side we stabilize the footage to reveal the full extent of the warehouse.

The sounds of fireworks begin to be heard at approximately 5:59 p.m. shows that there are many windows and doors are closed according to the expert the confinement creates hot spots, high temperature areas in which the ammonium nitrate can approach its combustion point, according to the media, the firefighters arrived approximately four minutes after an initial call was made to the station at 5:54 pm In these images taken by firefighters upon their arrival at the scene, the sound of fireworks can still be heard. 2,750 tons of ammonium nitrate were unloaded in this hangar in October 2014 and in December of that year several port and customs officials warned.

Of the dangers posed by their storage, many subsequent warnings were issued in February 2015, for example, a forensic chemistry expert commissioned by the Lebanese courts to report on the status of stored ammonium nitrate described that 70 of the bags were opened and Its contents spilled and some of the glass had darkened. Leaked images from February 2020 indicate that storage conditions had not improved. The bags were still open and their contents were still spilling out. The bay numbers visible on the ceiling allowed us to place these bags in bays 9 and 10. The images show the presence of a container and a stack of wooden pallets.

Another video taken on December 18 published by media outlet Al Jadeed shows the state of ammonium nitrate bags stored in compartment 6 and the surrounding door 9. Stacked ammonium nitrate bags block the entrance. entrance here we can see the base numbers 4 and 5. To the right of the cameraman between doors 9 and 10 you can see a white wall that suggests the presence of a small service room. These videos and images allowed us to map a total of 243 bags of ammonium nitrate in space given the location of the source of the spherical column here in bay eight the remaining two thousand five hundred and seven bags of ammonium nitrate should have been stored here occupying almost two thousand square meters of space, but given the haphazard way in which the visible bags are stored the space occupied by the entire stockpile was probably larger.

News reports suggest that, in addition to the ammonium nitrate, the warehouse also stored 23 tons of fireworks 50 tons of ammonium phosphate 5 tons of tea and coffee 5 rolls of slow fire detonating cord and 1,000 car tires each of these materials burns differently the combustion of tires, for example, produces a dark and thick column depending on The explosives expert could correspond to the dark column we had located in the northeast corner of the warehouse, so he placed the tires approximately here. The expert also told us that the white column that appeared in the northwest of the warehouse corresponds to the lighting of fireworks.

Therefore, we placed the fireworks approximately in this corner from an engineering perspective. This is the spatial layout of an improvised bomb. On the scale of a warehouse awaiting detonation, according to Gareth Collett, ammonium nitrate is extremely difficult to detonate with fire alone; However, when confined and contaminated, this can lead to catastrophic detonation. It is sensitized by the presence of even the smallest amount of additives and therefore must be separated we review international standards for the storage of ammonium nitrate internationally accepted reference points include British regulations according to British standards nitrate batteries of ammonium must be limited to 300 tonnes and each pile must be at least one meter away from walls and other piles Australian standards are more Strict bags must be arranged in piles of 500 tonnes, but must be stored 890 meters away from the nearest residential buildings.

Using their equation for calculating safe distances, we can determine that a 2750 stack of ammonium nitrate should have been stored 1570 meters away from the nearest residential building. NASA's damage map illustrates the magnitude of the explosion. All of these regulations prohibit the storage of combustible or explosive materials, such as tires or fireworks, near ammonium nitrate. This fact highlights the substantial and sustained state negligence that led to the making of an improvised bomb around 1,000 of the survivors and the families of the victims have called for an independent investigation and public access to all relevant documents as the search for responsibility continues. political and economic by the explosion of August 4.

Ms. Mass's forensic architecture is making the model, the geolocated videos and the source. material used in research publicly available through this link, you