CHST Worksite Audit Practice Test

Polychlorinated biphenyls (PCBs) were historically used as insulating fluids in electrical equipment and in certain industrial materials. Because of that, the locations you’d most expect to encounter PCBs on a worksite are where such materials are kept or used: transformers that contain PCB-containing insulating oil, and fluorescent light ballasts that historically included PCBs. Some foundry or manufacturing processes could involve PCB-containing substances in materials like investment casting waxes, so those sites can also be sources. Drains, by contrast, aren’t a primary source for PCBs—they’re more of a pathway for contamination if leaks occur, not a common location where PCBs are routinely found or stored.