It is proposed to hold a conference on the scientific basis of biological monitoring of metals. The subject areas will include pharmacokinetics and metabolic models, the application of new in vivo techniques for determining tissue levels and a consideration of new and unusual forms of metals now being employed in advanced and emerging technologies. Metal toxicity continues to be a matter of public health concern as new dimensions of low exposures are realized. The topic for this conference is central to assessing this concern and has not been reviewed in depth for at least the last decade.