Manufacture of PCBs was halted in the 1970s, but some PCBs may still be found in transformers, capacitors, heat transfer systems and hydraulic systems. Even when not required by regulations, the following best practices are recommended:
- All PCB transformers should be leak proof.
- Buildings used to store transformers should have a roof and walls that prevent rainwater from reaching the stored material and items; the floor should be impermeable with continuous curbing that is a minimum of 6" high.
- No drain valves, floor drains, expansion joints, sewer lines or other openings that would permit liquids to flow from the curbed area should be present in buildings/areas used to store transformers.
- The floor and curbing in the building/area used to store transformers should be constructed of continuous smooth and impervious materials, such as Portland cement concrete, to prevent penetration of PCBs.
- The storage facility should be located above flood water level.
- Transformer oil should be stored in proper storage containers such as steel drums without a removable head designed, constructed and operated with safety requirements for flammable and combustible liquids.
- All transformers should be labeled with respect to the PCB content of the transformer oil (e.g., "Non-PCB Containing Oil") and the labels should be maintained in legible condition.