The chemical properties of excellent stability, non-combustion, low conductivity, and difficult bio-degradation make PCBs widely applied in power supply, liquid pressure transferring, and thermo transit equipments. PCBs can be used as high efficient support for textile.

The degradation of PCBs is extremely slow in natural environment. They are long life of environmental pollutants, and can be immigrate into atmosphere, soil, and aquatic environment and then transferring along the food chain. PCBs have demonstrated as one of the chemicals which have negative effects to food safety and environmental heath.

PCB and PCT are dangerous to human heath and environmental safety, especially the products when combustion of PCB and PCT. They were limited to use in Guideline 76/769EEC, and then revised 83/478 and 85/467, in which PCBs (with exception of compounds contained 1 and 2 Chlorine) and PCT were forbidden, and the mass concentration of PCB and PCT is lower than 0.005% for materials.