This large of an explosion it's most likely accidental. Hopefully. Think Texas chemical plant explosion or Tianjin China explosion where there were illegal chemicals stored in shipping containers like calcium carbide or ammonium nitrate, or nitrocellulose. In Tianjin a fire started, firefighters were called but they didn't know they were spraying water on a container of calcium carbide, the reaction produced massive amounts of acetylene gas, the resulting explosion from the acetylene gas detonated a storage container of ammonium nitrate.
An explosion that large was NOT solely caused by a fireworks warehouse, let's be clear.