Sounds like there's a lot of he-said she-said with why the explosive materials were basically left unattended in the warehouse since 2013.
According to the Wall Street Journal, the ship carrying them in 2013 had mechanical problems, cancelled their shipment and just left everything there. And then disposal of the materials got tied up in jurisdiction and deciding who should be responsible for getting rid of them.
Absolutely terrifying stuff though. You'd have to think that many of us at some point in our lives have been incredibly close to some kind of dangerous material being transported or housed somewhere.