A video has been uploaded to YouTube claiming to depict an accidental "explosion of a whole position [sic] of fireworks mortars in Italy."
The user, hhhjjjjffff, who uploads fireworks videos from all over Europe, told BuzzFeed News that "No one was injured seriously, just little scratches."
But the YouTube user wouldn't specify where in Italy the accident happened, saying: "I do not want to say where it was exactly, don't want to cause anyone trouble."
Which is good, because it looks pretty bad.
The massive amounts of fireworks with salute effect shot into the air during a display is normal. But at one of the positions shooting the effects in the air, something exploded in the mortar on the ground, and all mortars next to it also caught fire on the ground and exploded at once, so this is the big explosion you see at the ground at ~0:15. Anyways, from all other positions the show continued normally. There are also high safety distances, and all "regular" people watching it were ~200m away, so out of the danger zone.