Two years ago, unnerving news from researchers in Stockholm hit the European
![](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2001/10/697.jpg?resize=74%2C150&ssl=1)
press. An analysis of samples of women’s breast milk since 1972 showed dramatic
increases in a class of relatively unknown chemicals that toxicologists liken to
the notorious pollutants polychlorinated biphenyls (PCBs).
The lesser-known chemicals, polybromo diphenyl ethers (PBDEs), had been noted a