Third or fourth degree heat (thermal) burns

An employee was unloading the hot melt glue from a heated reservoir of a glue application machine. He unloaded the unit into a medium-sized cardboard box. The volume of material was about 2 gallons. He then immediately carried the open-top cardboard box outside to the dumpster. He attempted to cleanly throw the box into the dumpster, but the box hit either the edge of the dumpster or something else and bounced back towards him. The hot glue was expelled from the box and landed on both of his bare hands and right bare arm. He suffered second and third degree burns.