Over the past 40 years, a class of chemicals with the tongue-twisting name of halogenated flame retardants has permeated the lives of people throughout the industrialized world. These synthetic chemicals - used in electronics, upholstery, carpets, textiles, insulation, vehicle and airplane parts, children's clothes and strollers, and many other products - have proven very effective at making petroleum-based materials resist fire.
Yet many of these compounds have also turned out to be environmentally mobile and persistent - turning up in food and household dust - and are now so ubiquitous that levels of the chemicals in the blood of North Americans appear to have been doubling every two to five years for the past several decades.
Acting on growing evidence that these flame retardants can accumulate in people and cause adverse health effects - interfering with hormones, reproductive systems, thyroid and metabolic function, and neurological development in infants and children - the federal government and variousstates have limited or banned the use of some of these chemicals, as have other countries. Several are restricted by the Stockholm Convention on persistent organic pollutants. Many individual companies have voluntarily discontinued production and use of these compounds. Yet despite these restrictions, evidence has emerged in recent months that efforts to curtail the use of such flame retardants - a $4 billion-a-year industry globally - and to limit their impacts on human health may not be succeeding.