Crafting a New Arsenic Rule

Arsenic has long been known to be harmful to human health at high levels of exposure. The regulation of arsenic, however, presents several technical and policy challenges to the US Environmental Protection Agency (USEPA). The complexity of the issues involved has caused the agency to miss several deadlines during its effort to prepare a primary drinking water regulation for arsenic, despite more than a decade of deliberations. The background, status, and issues involved in the development of this regulation are reviewed in this article.