长期以来，人们都知道砷在高暴露水平下对人类健康有害。然而，对砷的监管给美国环境保护局（USEPA）带来了一些技术和政策挑战。尽管经过十多年的审议，但由于所涉问题的复杂性，该机构在为砷制定初级饮用水法规的过程中错过了几个最后期限。本文回顾了该法规制定的背景、现状和涉及的问题。包括23个参考文献，表1。

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 efforts 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. Includes 23 references, table.