The Toxics Release Inventory (TRI) calculates various measures of exposure to toxic chemical releases and waste disposal. Based on reports from industrial and federal facilities, the most comprehensive of TRI measures are called the Risk-Screening Environmental Indicators (RSEI). For any particular zip code in the country, it gives us a measure of inhabitants’ exposure based on three things—the volume of chemical releases, the degree of toxicity of those chemicals, and the size of the exposed population.
