China has been accepting vast quantities of discarded televisions, computers, printers, and other equipment from abroad since the early 1990s. E-waste processing, a burgeoning cabin industry in coastal parts of China, may end up dwarfing other examples of contamination, scientists argued at a symposium. The roster of substances liberated during e-waste processing is a toxicological nightmare: They include known carcinogens like dioxins and polycyclic aromatic hydrocarbons; neurotoxic elements like lead; and brominated fire retardants, including polybrominated diphenyl ethers, which have been shown to disrupt endocrine hormones in lab animals and wildlife. Since 2000, the central government has prohibited importation of e-waste, and a law passed last year requires e-waste processors to register with local governments and take steps to control pollution.