About the data
The Toxics Release Inventory (TRI), compiled by the U.S. Environmental Protection Agency (EPA) in accordance with the Emergency Planning and Community Right-to-Know Act of 1986, annually reports the weight (in pounds) of each of approximately 600 toxic chemicals released into the environment by major industrial facilities in the United States. In all, TRI-reporting facilities released slightly under 230 million pounds of toxic chemicals into water in 2014. (The weight refers to the chemicals themselves, not including solutions or sludge carrying the chemicals.)
The Political Economy Research Institute at the University of Massachusetts AMHERST uses the Toxic 100 Water Polluters index to identify the top U.S. air polluters among the world's largest corporations.