Pennsylvania pipefitters and steamfitters at US Steel, Bethlehem Steel, Sun Oil, and Philadelphia Electric plants routinely applied and disturbed asbestos pipe covering and block insulation from the 1940s through the 1970s.

Union locals: UA Local 420 (Wilkes-Barre/Scranton) · UA Local 157 (Pittsburgh) · UA Local 89 (Philadelphia) · UA Local 542 (Philadelphia — Heavy & General Construction)

Asbestos-insulated steam lines, heat exchangers, and valve packing were ubiquitous in Pennsylvania industrial facilities throughout this era.