2,4,4-Trichlorobiphenyl (PCB-28)

Legacy Aroclor PCBs in old transformers/capacitors, caulk and paints; leaks or improper disposal; releases from contaminated sites; and volatilization to indoor air from older building materials [1][2].

Mainly by eating contaminated fish/seafood, meat, and dairy; also by breathing indoor/outdoor air and dust near older buildings or industrial areas, and contact with polluted soil or sediments [1][2].

PCBs can harm the immune, thyroid, and reproductive systems and may affect children’s brain development; PCBs are carcinogenic to humans [1][3][4].

Pregnant people, infants/children, frequent consumers of locally caught fish, residents of older buildings with PCB caulk/ballasts, and demolition/remediation or electrical workers [1][2].

Follow local fish advisories; choose lean cuts, trim fat, and broil/brush off drippings; ventilate and HEPA-vacuum dust; avoid disturbing old caulk/ballasts—use certified abatement; wash hands and damp-wipe surfaces [1][2].