Someone is trying to make Syrian refugees into Girardian black sheep. This wouldn't be the first time. The irony is that Bashar Al Assad used nitrate-filled barrel bombs to decimate the Syrian people, and he is supported by Hezbollah and Iran, which have a huge influence in Lebanon. Their influence cannot be separated from the incompetence and corruption that led to the blast.
Here's the really crazy part: some people are saying that a lot of the nitrate which was originally stored must have been smuggled out, because otherwise the blast would have been larger. If true, it wouldn't be surprising that the nitrate was smuggled for Assad to use in barrel bombs.
Here's a list of barrel bombs dropped by the Syrian Air Force. That's a lot of nitrate...: https://en.wikipedia.org/wiki/List_of_Syrian_Civil_War_barre...