Who did Jeff hardys firework accident?

Answer 1

it was edge before calling him to the ring he set up the fireworks where he would be standing so it would hit him and Jeff hardy would have to drop out the match

Edit - Storyline wise, it was Matt Hardy. Matt Hardy was the one who attacked Jeff Hardy all three times - before Survivor Series, thus making Jeff Hardy not show up for his WWE Championship match, the "hit and run" accident and the pyro/firework accident.

Now in real life, it was obviously the trained professionals who set up the angle for Jeff Hardy, who sold the injury good enough.