The extent to which mercury in the environment poses a risk to human health has been debated for years. While the dangerous effects of high levels of methylmercury—the mercury compound of primary public health concern—are well known, questions remain regarding the health effects, if any, of low levels of methylmercury in the diet, particularly among children, infants, and the developing fetus. Recently, the United States Environmental Protection Agency (EPA) proposed regulating mercury emissions from power plants that burn coal to create electricity. While one might assume this would be an effective means of both reducing environmental mercury levels and of improving public health, the scientific evidence is much less certain.

This booklet, based on a more technical report, examines the scientific evidence underlying claims of those for and against the regulation of mercury emissions, with the aim of determining the impact, if any, such regulation will have on public health. Specifically, it focuses on the health effects associated with methylmercury and examines the question of whether limiting mercury emissions from coal-burning plants in the US would reduce environmental methylmercury levels, and therefore, human exposure.