The hazard
Dust, fumes, mists, gases and vapors can damage your lungs, sometimes without any warning you can see or smell. Controlling the hazard at the source comes first, with ventilation, water or a safer product. When a respirator is still needed, it only protects you if it is the right type, fits your face and is worn and cared for the right way.
The action
Leave the area if you smell or taste the contaminant, if breathing gets harder or if the facepiece leaks. Your employer must make sure you leave the respirator area for those reasons, and also to wash your face or to change the filters or cartridges. Do not go back in until the respirator has been repaired or replaced (29 CFR 1910.134(g)(2)(iii)). (29 CFR 1910.134(g)(2)(ii))
ASK THE CREW
Which tasks on this job need a respirator, and which type does each one need?
From the talk: Respiratory protection. Read it in full, free, with the questions and the sign-in sheet.