Polychlorinated biphenyls (PCBs), terphenyls (PCTs) and naphtalens (PCNs) are widely applied in various areas. They are mainly used as dielectric fluids and substances (electric insulation) in transformers, capacitators, and other electromagnetic devices. Damaging this equipment may lead to environmental contamination. Fire or explosion would generate extremely toxic dioxins and furans. It is because of these properties, that limitations on the applications of these substances or the total ban on their production have been introduced in a number of countries. The author presents the EU legislation on phasing out these substances.