Hexachlorobiphenyl

Legacy PCB mixtures (e.g., in old transformers/capacitors), hydraulic fluids, fluorescent light ballasts, and some 1950–1979 caulks/paints; contaminated soils/sediments and waste/recycling sites [1][2].

Eating contaminated fish, meat, and dairy; swallowing dust from old building materials; workplace contact during demolition/e-waste or equipment servicing; PCBs can pass to infants during pregnancy and through breast milk [1][2].

PCBs are persistent and bioaccumulative; linked to immune, thyroid, reproductive, and neurodevelopmental effects, skin and liver changes, and increased cancer risk (IARC Group 1; NTP known human carcinogen) [1][3][4].

People who eat a lot of locally caught fish/wildlife, pregnant people and young children, workers in demolition/electrical recycling, and communities near contaminated sites [1][2].

Follow local fish advisories and trim fat/skin; wet-wipe/vacuum with HEPA to reduce dust; avoid disturbing old caulks/ballasts—use certified removal; use PPE and hygiene at work; dispose of PCB wastes properly [1][2].