Times of Israel reports: “Director-General of Lebanon Public Security Abbas Ibrahim says: The storage area contained highly explosive materials confiscated years ago.”
I am guessing that included some liquids/gases, that produced that huge secondary fuel/air explosion. Maybe some liquid rocket propellant and oxidizer?
There were many smaller secondary detonations, before the big one went off, so maybe there was a variety of armament and ammunition stored there.
As much as this is the Middle East, and conspiracy theories are the rule, a lot of industrial accidents happen in handling some touchy materials. Poor storage conditions (lack of adequate separation), and just a bit of bad luck could well have produced this.
It’s great to finally get an informed take. Thanks.