Companies in many industries, including the electric utility industry, are required to report to the U.S. Environmental Protection Agency specific amounts of certain chemicals handled or released annually. This report is known as the Toxics Release Inventory, or TRI.

The report, or inventory, does not represent new emissions but rather is a reporting requirement under the Emergency Planning and Community Right-To-Know Act.

The purpose of the report, which is filed with the EPA each July 1, is to make communities aware of the chemicals being produced and used.