US Environmental Protection Agency's (EPA) Office of Research and Development National Center for Environmental Research, and National Health and Environmental Effects Research Laboratory, Office of Environmental Justice, and Office of Children's Health Protection, the Centers for Disease Control and Prevention's (CDC) National Center for Environmental Health, the National Institute of Environmental Health Sciences and The National Institute for Occupational Health and Safety are cosponsoring a 2 ½ day small-sized technical symposium on disproportionate environmental health impacts. The overall goal of the Symposium is to lay the foundation for developing analytical and decision frameworks that can be used by EPA and other federal, state, local governments to better quantify and characterize disproportionate environmental health impacts on minority and low income populations that may result from their programs, policies, and activities. Specifically, the Symposium revolves around commissioned technical papers on seven factors that may result in disproportionate environmental health impacts among minority and low income populations. These factors are: 1) proximity to environmental hazards, 2) susceptibility/vulnerability, 3) unique exposure pathways, 4) multiple and cumulative environmental burdens, 5) diminished ability to participate in the decision making process, 6) physical infrastructure, and 7) chronic community stress. The Symposium aims to: 1) elucidate how these and other factors are associated with differential burdens of environmental exposures, vulnerability, and health impacts; 2) identify relevant data sources and methods for analysis of these factors; and 3) explore frameworks for assessing disproportionate burdens of environmental exposures and disease. The Symposium will feature interdisciplinary presentations, discussions, and technical input on the scientific basis for factors that may cause disproportionate environmental health impacts, and frameworks for assessing disproportionate burdens of environmental exposures and disease.