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
Do a user seal check each time you put on a tight-fitting respirator, the way you were trained. Your employer cannot let you wear one if facial hair comes between the face seal and your skin or gets in the way of the valves (29 CFR 1910.134(g)(1)(i)). Even stubble can keep the facepiece from sealing. (29 CFR 1910.134(g)(1)(iii))
ASK THE CREW
What would you do if you smelled the chemical through your respirator?
From the talk: Respiratory protection. Read it in full, free, with the questions and the sign-in sheet.