Under the Pollution Prevention Act of 1990 (PPA), TRI collects information to track industry progress in reducing waste generation and moving towards safer waste management alternatives. Measures that facilities have taken to prevent pollution and reduce the amount of toxic chemicals entering the environment are shown in the table below. Although factors other than these reported practices contribute to year-to-year changes in releases, results are sorted by largest reduction in order to facilitate identification of pollution prevention successes. View the to learn about this report's features.