Working in Category 3 or Category 4 PPE can be hot, difficult and result in loss of dexterity and vision. Some workers argue that while working in Category 4 PPE provides them more protection in the event of an accident, they are more likely to make a mistake and cause and accident when wearing Category 4 PPE. If the work does not require this for safety purposes, the worker should not be exposed to this. Also, sometimes a situation exists where hazard levels are greater than 40 cal/cm2, aka over Category 4.