PCBs are synthetic organic chemicals containing the biphenyl molecule, which have been chlorinated to varying degrees. Their physical state ranges from oily, yellow liquids to waxy solids. Due to their properties, PCBs were used in numerous applications including as insulating fluid in transformers and other electrical equipment including fluorescent light ballasts, capacitors, motors, circuit breakers, switches and pumps. Generally, materials are considered PCBs if they contain 50 parts per million (ppm) or greater PCBs by weight. However, many disposal facilities will not accept materials containing any PCBs.