 levels of the polybrominated diphenyl ethers ( pbdes ) , a class of widely used flame retardants , appear to be rising rapidly in human tissues , as evidenced by studies of human breast milk . 
 the case of the pbdes illustrates the value of breast - milk monitoring programs in identifying important emerging pollutants , and highlights why such monitoring programs are needed in the united states . 
 a review of the use , occurrence , and toxicity of pbdes indicates many parallels between some pbdes , pcbs , and other polyhalogenated persistent organic pollutants , and suggests that the pbdes may be a significant environmental challenge in the future.imagesfigure 1figure 2 
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