Although scientific evidence is scarce and uneven, there are mounting concerns that environmental health risks are borne disproportionately by members of the population who are poor and nonwhite. From an environmental health perspective, research to reduce critical uncertainties in health risk assessment must necessarily be at the heart of efforts to evaluate and resolve issues of environmental justice--helping to define the dimensions of the problem, understand its causes, and identify effective and efficient solutions. The full range of environmental health sciences, including exposure analysis, epidemiology, toxicology, biostatistics, and surveillance monitoring, is needed to build a strong scientific foundation for informed decision making. This is the best and surest way to promote health and safety for all members of our society, regardless of age, ethnicity, gender, health condition, race, or socioeconomic status.