Answer: All have something wrong with them!!!
Explanation: #1: He is using chemicals without using any goggles or protection
#2: She is unsupervised while around fire as well as no protection
#3:
#4: There are many flammable things around the fire especially since its paper it could start a major fire
#5: Again has no protection (goggles. gloves, e.t.c.) and putting chemicals close to your face is just a Don't in science
#6: They are "horseplaying" and also someone else is doing all the work