Exposure to air toxics in urban areas may be of significant concern because people and sources of emissions are concentrated in the same geographic area. Studies show that levels of some air toxics tend to be similar across the country, while others can vary significantly from one location to another. Understanding which air toxics in an urban area contribute the most to potential health risks can provide valuable information in developing strategies to reduce these risks. The Detroit Air Toxics Initiative (DATI) project was initiated to gather this information for the Detroit area, and use it to help reduce exposure to air toxics to people living in this area. The DATI project consists of two components: one to assess the health risks from exposure to air toxics in the Detroit area, and the other to fund projects to help reduce identified risks. A stakeholder group consisting of representatives from community and environmental based groups, federal, state and local government, industry and academia is providing assistance with the project. This report provides the background, methodology, and results for the risk assessment phase of the project.