Many residential areas are also home to industrial facilities that emit toxic chemicals and other forms of pollution. On issues of environmental quality and health in these communities, scientists and residents often talk past one another: residents’ claims about the harms of industry tend not to meet the standards of scientific study, while scientists’ studies tend not to address residents’ complaints. Community-based science—defined as studies conducted by residents and scientists working in collaboration—is seen as one possible solution. This paper outlines the characteristics that make community-based science effective and summarizes major challenges to creating successful scientist-community collaborations. It recommends ways to overcome those challenges, in large part by meeting obstacles at the structural or institutional level.