What are the effects of polychlorinated biphenyls in transformer oil?

Polychlorinated biphenyls (PCBs) in transformer oil can have several detrimental effects. PCBs are toxic and can lead to environmental contamination when transformer oil leaks occur. They can also degrade the insulating properties of transformer oil, reducing its effectiveness in electrical insulation and heat dissipation. Additionally, the presence of PCBs in transformer oil poses health risks to humans and wildlife, necessitating strict regulations and monitoring in power transformer operations.