Remarkable advances in analytical chemistry now make it possible to measure minute levels of both natural and synthetic compounds in human tissue and body fluids. This “biomonitoring” allows researchers to determine more precisely than ever the degree to which individuals have been exposed to specific chemicals in the environment, and how exposures change over time. Consequently, federal and state officials increasingly regard biomonitoring as a potential new underpinning of environmental and public health regulations.

There is a great deal to be said in favor of basing regulations on actual exposure data, rather than relying on hypothetical modeling or extrapolations of animal studies, as currently is the case. But while biomonitoring certainly offers enormous opportunities for increasing our knowledge and understanding of chemical exposures, caution must be exercised in its application and interpretation. There are limitations to what biomonitoring can reveal, and its misuse will sow confusion, fear and misguided policies.

In this paper, we examine current biomonitoring programs and the benefits of their broader use. We also describe valid interpretations of biomonitoring data and conclude with recommendations for public policy.