The authors invoke a population health perspective to assess the distribution of environmental hazards according to race/ethnicity, social class, age, gender, and sexuality and the implications of these hazards for health. The unequal burden of environmental hazards borne by African American, Native American, Latino, and Asian American/Pacific Islander communities and their relationship to well-documented racial/ethnic disparities in health have not been critically examined across all population groups, regions of the United States, and ages. The determinants of existing environmental inequities also require critical research attention. To ensure inclusiveness and fill important gaps, scientific evidence is needed on the health effects of the built environment as well as the natural environment, cities and suburbs as well as rural areas, and indoor as well as outdoor pollutants.