The scale of the blast – which could be felt as far away as Cyprus – appears similar to other incidents where ammonium nitrate has exploded, experts have said.
But the chemical, which is used as an agricultural fertiliser, is unable to explode on its own. While it is a powerful fuel for explosions, because it includes both the fuel and oxygen required for a fire – and has been used as such in terror attacks – it still needs to be ignited by heat, since it cannot detonate on its own.
Early videos suggest the fireworks could have played that role. Videos show a small initial fire, accompanied by the small sparks and pops of fireworks going off, before the large explosion happens and engulfs the city around it.
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That larger blast had all the hallmarks of being caused by ammonium nitrate. After it had cleared, orange clouds could be seen, which are probably toxic nitrogen dioxide gas that is released by explosions that involve nitrates.
The white cloud that came alongside the massive blast and quickly spread through the city appears to be a condensation cloud. Those typically accompany massive explosions in humid conditions, following the shock waves, according to Jeffrey Lewis, a missile expert at the Middlebury Institute of International Studies in Monterey, California.
Source
The Independent