... C6H6,CL2 SO2 1.Purpose and CharacteristicMF25 half face piece gas mask is apply to the workers, who work ... using, check all the parts of the half face piece is ready or not. If there is something leaky ... out.3.3 The user needs to wear the face piece before going into the gas workplace. During the using ... if necessary.3.4 After using, the half face piece should be cleaned by alcohol or 1% peracetic acid, ...