Polybrominated diphenyl ethers, or PBDEs, are a class of fire-retardant chemicals that are ubiquitous. They are found on upholstery, carpets, curtains, electronics, and even infant products. Flame retardants migrate out of products into dust that humans contact and can ingest. Considered to be global environmental pollutants, they have been detected in water, soil, air, food products, animals, and human tissues. They are found, too, in breast milk of women all over the world.