PCBs Taint Paints, with Titanium Dioxide Bearing Some Blame

Long-banned toxic chemicals still contaminate building products and consumer goods thanks to a loophole in 1970s regulations.

Trace amounts of highly toxic PCBs (polychlorinated biphenyls) are ubiquitous in food packaging, office supplies, and certain building products, according to an analysis from the Washington State Department of Ecology. These aren’t traces left in the environment from older products (“legacy” PCBs) but rather compounds formed during current manufacturing processes that involve chlorine.

Health risks from direct exposure to these products have not been thoroughly studied. But officials worry that tainted pigments and dyes may be contributing to PCB pollution in the Puget Sound watershed—pollution that persists despite decades-old federal laws banning intentional production of the chemicals.

Thirteen of the fourteen paint products tested contained detectable levels of at least one PCB cogener, or chemical “family member.” Concentrations went from background levels up to 320 parts per billion (ppb), with yellow and green colorants apparently contributing to the highest concentrations of PCB-11, a byproduct of manufacturing certain yellow pigments.

A titanium dioxide (TiO₂) paint colorant contained 1.26 ppb of PCB-209, a high-molecular-weight cogener. PCBs are a byproduct of TiO₂ manufacture, which, according to the report, involves converting TiO₂ ore into titanium tetrachloride (TiCl₄) through the addition of chlorine. The report notes that one TiO₂ manufacturer recently paid a $13.8 million fine to the U.S. Environmental Protection Agency for illegal dumping of PCB-contaminated waste.

Current U.S. regulations do not require manufacturers to eliminate PCBs if the compounds are created as byproducts.