DISCLAIMER: I’m not a lawyer and I’m not your lawyer and this is not legal advice. If you need legal advice seek it from someone else. You should seek a lawyer ASAP as you may have claims that could become barred by the running of time.
Not sure if this is a crime, but if someone was indeed burned then they could probably try civil negligence. I think assault may work as well if a reasonable person in the same position would have been substantially certain that a burn would have occurred. Considering these guys are professionals at this, I would think that people in the industry would know what shining the light on someone would do. If it could indeed burn someone that quickly then intent may well be there.
Yes, the Teamsters were douchebags. Unfortunately, in LA it's the movie/television business that pays the bills, so when the union thugs have the right permits, they get to be douchebags. That's life in LA.