Explosion de Beyrouth : le désastre reconstitué

shortly after 6 pm on august the 4th an explosion ripped through the port of beirut it killed more than 200 people wounded over 6500 and destroyed large parts of the city forensic architecture was invited by madam mass to examine open source information including videos photographs and documents to provide a timeline and a precise 3d model to help investigate the events of august the 4th the model is available via this link the first photograph of the warehouse on fire was uploaded to twitter at 5 54 pm we carefully geo-located this photograph by identifying the key buildings and calculated the camera's cone of vision in this image we identified the location of the source of the smoke plume at the northeast corner of warehouse 12. smoke plumes are continuously transforming and have a unique shape at every moment we modeled the plume at this crucial stage to help synchronize other videos without a timestamp a video shot around the same time from one of the balconies of the residential tower building shows the same source of fire clearly on the same side of the warehouse the shape of the plume and the heat source suggests that the fire had evolved another video starting at 5 58 pm from the nearby st george hospital provides 10 minutes of uninterrupted footage of the warehouse within two minutes the smoke thickens and its color changes to a darker shade according to gareth collett a un explosives analyst we consulted this suggests that the material burning inside the warehouse has changed at 6 07 pm a new intense heat source appears on the other north western side of the warehouse here followed by a different larger plume the sparks that follow suggest the presence of small explosive charges such as fireworks 35 seconds later at 608 pm a large spherical plume appears above the center of the warehouse according to the explosives analyst the symmetrical shape of the sphere suggests that it's a single point explosion originating in one particular place within the warehouse and it's possible that as little as half of the 2750 sacks of ammonium nitrate stored inside detonated we use the shape of the two plumes from these explosions as metadata to synchronize the remaining footage this video taken from further back provides an uninterrupted view of the events that followed within the span of nine seconds the spherical plume projected high into the atmosphere several tons of particulates thick in the air and a red coloured plume 755 meters high rose over the warehouse we have thus identified four types of smoke plumes emanating from different parts of the warehouse within the space of these 14 minutes the first plume at 5 54 pm emanates from the northeast corner of the warehouse second plume at 6 pm is from the same source point but has a darker colour the third plume appears on the northwest side of the warehouse at 607 pm the final plume is developed from a spherical explosion located at the center of the warehouse at 608 pm each of these smoke plumes with their distinct shape and colour provide indications as to the arrangement of goods in the warehouse the way the fire developed and the layout of what was stored inside a close-up examination helps in understanding the evolution of fire inside the warehouse early footage shows smoke leaking out of every opening including the windows and the ceiling vents from this point at about 5 56 pm the temperature inside the warehouse started rising rapidly the smoke is visible as it changes color to a darker shade in this footage from the east side we stabilized the footage to reveal the full extent of the warehouse the sounds of fireworks starts being heard at approximately 5 59 pm it shows that many windows and doors are shut according to the expert confinement creates hot spots areas of high temperature in which ammonium nitrate can get close to its combustion point as reported by media outlets the fire brigade arrived approximately four minutes after an initial call was made to the station at 5 54 pm in this footage taken by the fire brigade on their arrival to the scene the sound of fireworks continues to be heard the 2750 tons of ammonium nitrate were unloaded to this hangar in october 2014 and as early as december of that year various port and customs officials warned of the dangers posed by its storage many subsequent warnings were issued in february 2015 for example a chemical forensics expert commissioned by the lebanese courts to report on the state of the stored ammonium nitrate described that 70 of the sacs were torn open their content spilling out and some of the crystals had darkened leaked images from february 2020 indicate that the storage conditions had not improved the sacs were still torn open and their contents were still spilling out the bay numbers visible in the ceiling allowed us to locate these bags in bay 9 and 10. the images show the presence of a container and a stack of wooden pallets another video taken on december 18th released by news outlet al jadeed shows the state of ammonium nitrate bags stored at bay 6 and surrounding door 9. stacked ammonium nitrate bags are blocking the entrance here we can see the numbers for base 4 and 5. on the right of the videographer between door 9 and 10 a white colored wall is visible suggesting the presence of a small service room together these videos and images allowed us to map a total of 243 bags of ammonium nitrate in the space given the location of the source of the spherical plume here at bay eight the remaining two thousand five hundred and seven bags of ammonium nitrate should have been stored here occupying almost two thousand meters squared of space but given the haphazard way the visible bags are stored the space the entire stockpile occupied was likely 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 burning detonating cord and 1 000 car tyres each of these materials burns differently the combustion of tyres for example produces a dark and thick plume according to the explosives expert it could correspond to the dark plume we had located on the north east corner of the warehouse so we placed the tyres roughly here the expert also told us that the white plume that appeared on the northwest of the warehouse corresponds to the ignition of fireworks we therefore place the fireworks roughly in this corner from an engineering perspective this is the spatial layout of a makeshift bomb on the scale of a warehouse awaiting detonation according to gareth collett ammonium nitrate is extremely difficult to detonate by fire alone however when confined and contaminated this can lead to catastrophic detonation it is sensitized by the presence of even the smallest quantity of additives and hence should be separated we reviewed international standards for the storage of ammonium nitrate internationally accepted benchmarks include british regulations according to british standards stacks of ammonium nitrate must be limited to 300 tons and each stack must be at least one meter away from walls and other stacks australian standards are more stringent bags must be arranged in 500 ton stacks but should be stored 890 meters away from the closest residential buildings using their equation to calculate safe distances we can determine that a 2750 stack of ammonium nitrate should have been stored 1570 meters away from the closest residential building nasa's damage map illustrates the extents of the blast all these regulations prohibit the storage of combustible or explosive materials such as tyres or fireworks in proximity to ammonium nitrate this fact highlights the substantial and sustained state negligence which led to the formulation of a makeshift bomb around 1 000 of the survivors and victims families have called for an independent investigation and public access to all relevant documents as the search for political and economic accountability for the explosion of august the fourth continues forensic architecture madam mass are making the model the geolocated videos and the source material used in the research publicly available via this link you

Channel: Mediapart

Views: 7,472,753

Keywords: Mediapart, révélations, beyrouth, explosion, forensic architecture, nitrate d'ammonium, port

Id: 3s54_MF2XPk

Length: 12min 0sec (720 seconds)

Published: Tue Nov 17 2020