We left my step son in charge with my girls

I have a step son who is 18. I also who 2 daughters who are 12 and 3. Me and my hubby were going to see his mom and left him in charge and trusted him to yake care of my girls. 4 hours into being at his moms I get a call. It's my 12 year old. She said to me "Mom... Dylan started a fire". I'm like wtf. I told her to put Dylan on the phone. I asked Dylan what happen. He says he doesn't know. He just put the pizza in the oven. He put the fire out with the fire extinguisher. He says he thinks the plastic caught on fire. I asked why theres plastic in the oven. He said "So I could cook the pizza"..... I said "Dylan did you put that pizza in the oven with the plastic on?" He says "Yeah"..... My brother is going over to keep everyone alive the rest of the time we are gone...