A chemical banned in the US 35 years ago is present in almost all yellow paper products and items of clothing, researchers warn. Though the production of polychlorinated biphenyls (PCBs), which contaminate the environment and are believed to cause cancer, was outlawed, PCB-11 is allowed to remain in yellow pigment because it counts as an unintentional byproduct of manufacturing, Scientific American finds. The researchers say it is present in "worrisome" levels—all 16 clothing items they tested, most children's clothes bought at US Walmarts, contained it—and people are in almost constant contact with the pigments, which are mainly manufactured in Asia.
Unlike some other PCBs, PCB-11 doesn't accumulate in people or animals, so its health effects have been little studied. But researchers in 2007 found it in air samples taken near Chicago schools; in a 2013 study of women from from East Chicago, Ind., and Columbus Junction, Iowa, researchers identified it in 60% of their bloodstreams. The paint industry is aware of the contaminants, but "as of right now, it’s an unavoidable byproduct in these pigments," says a spokesman for an industry association. In Washington state, a lawmaker brought in a bill requiring the state to buy PCB-free products where possible after learning that the yellow ink on one box of Cheerios contained enough PCB-11 to be detected at a water treatment facility, the Spokesman-Review reports.