Employee #1 was shutting down the system where molten resin goes through a filter prior to being cooled and processed on the belt. The employee tried to clean the material from the filter using nitrogen. The O-ring on the filter failed, allowing hot molten resin to spray out. The employee moved away from the area thinking that the pressure was relieved from the filter. When he returned with another employee, more molten resin sprayed out, burning both employees.