The hazard
Asbestos is still in many older buildings, in insulation, flooring, roofing and other materials. Disturbing it can release fibers too small to see, and you can breathe them in without knowing it. Those fibers can cause lung cancer, mesothelioma and asbestosis, often many years later, and smoking makes the lung cancer risk worse. You cannot tell asbestos by looking at it, so if you are not sure, stop and ask.
The action
In buildings constructed no later than 1980, thermal system insulation on pipes, boilers and ducts, and sprayed or troweled-on surfacing like fireproofing and acoustical plaster, are presumed to contain asbestos (29 CFR 1926.1101(b)). Asphalt and vinyl flooring installed no later than 1980 must also be considered asbestos-containing unless an industrial hygienist determines it is not (29 CFR 1926.1101(k)(1)(i) and (g)(8)(i)(I)). Wallboard, roofing, siding, mastics and gaskets can contain it too. (29 CFR 1926.1101(b))
ASK THE CREW
Which buildings or materials on our jobs could contain asbestos?
From the talk: Asbestos awareness. Read it in full, free, with the questions and the sign-in sheet.