Of the many chemicals that can pollute the world's water supplies, 1,4-dioxane is one of the most persistent. Listed as a likely carcinogen by the U.S. Environmental Protection Agency (EPA), 1,4-dioxane is largely unregulated and difficult to remove from water. A new article in Chemical & Engineering News, the weekly newsmagazine of the American Chemical Society, explores the challenges of combatting this contaminant.