4,4-Dichlorobiphenyl (PCB-15)

Old transformers/capacitors and fluorescent light ballasts; older building materials (caulk, paints) and contaminated soil/sediment; some PCBs are unintentionally formed in pigment/dye production; lighter congeners can travel in air [1][2][4].

Eating contaminated fish/seafood, meat, and dairy; breathing indoor air/dust in older buildings or near waste sites; workplace contact; transfer during pregnancy and via breast milk [1][2].

PCBs can cause cancer (IARC Group 1) and harm brain development, immune function, liver, and thyroid; risks rise with higher and longer exposures [1][3].

People who eat a lot of locally caught fish, live/work in older buildings with PCB materials, workers in electrical/demolition/remediation jobs, pregnant people, infants, and young children [1][2].

Follow fish advisories; choose lean cuts and trim fat; wet‑wipe/HEPA‑vacuum dust and ventilate; don’t sand old caulk/paint; use qualified pros for PCB equipment/materials; follow EPA building guidance [1][2].