The Toxic 100 Air Polluters index identifies the top U.S. air polluters among the world's largest corporations. The index relies on the U.S. Environmental Protection Agency's Risk Screening Environmental Indicators (RSEI), which assesses the chronic human health risk from industrial toxic releases. The underlying data for RSEI is the EPA’s Toxics Release Inventory (TRI), in which facilities across the U.S. report their releases of toxic chemicals. In addition to the amount of toxic chemicals released, RSEI also includes the degree of toxicity and population exposure. The Toxic 100 Air Polluters ranks corporations based on the chronic human health risk from all of their U.S. polluting facilities. The top ten polluters are listed below.