Mask Only is very useful in sealed shelters. The MOPP level should be automatically upgraded if the shelter is penetrated. Use Flowchart 3 to determine if the MOPP level can be modified. Subordinate units with MOPP guidance from higher headquarters can not downgrade the designated MOPP level except for the reasons listed in Flowchart 3. Ensure that all soldiers are wearing the appropriate clothing and equipment for the directed MOPP level.
Protective masks fit properly and are sealed.
Bottom of mask does not cut into throat. Mask does not bulge around edges or press so tightly that eyes partly close. Check the protective mask for leaks. While covering the inlet valves or inlet ports, have the soldier inhale and hold his or her breath for ten seconds. The mask should collapse to the face and remain collapsed for the entire test.