This study analyzes the social and geographic distribution of ecological hazards across 368 communities in the Commonwealth of Massachusetts. Combining census data with a variety of environmental data, we tested for and identified both income-based and racially based biases to the geographic distribution of 17 different types of environmentally hazardous sites and industrial facilities. We also developed a composite measure of cumulative exposure to compare the relative overall risks characteristic of each community. To the best of our knowledge, this point system makes this the first environmental justice study to develop a means for measuring and ranking cumulative exposure for communities. The study also controls for the intensity of hazards in each community by accounting for the area across which hazards are distributed. The findings indicate that ecologically hazardous sites and facilities are disproportionately located and concentrated in communities of color and working-class communities. The implication of this research for policymakers and citizen advocates is that cumulative exposure of residents to environmentally hazardous facilities and sites should receive greater consideration regarding community demographics and environmental health indicators. We conclude that the provision of additional resources for environmental monitoring and ranking, as well as yearly progress reports, is necessary for communities and state agencies to achieve equal access to clean and healthy environments for all residents.