Clearing the Air
The Toxic Release Inventory (TRI) is a database prepared by the Environmental Protection Agency (EPA) to document chemical "releases" at industrial facilities. The TRI was created in response to legislation designed to ensure public access to information about potentially harmful chemicals.
Details about emissions from coal-fired power plants that provide power to TEP customers are included in the TRI. But the reports lack details about how much of a plant's emissions are actually associated with a particular utility's service. Because many power plants have multiple owners, emissions levels must be adjusted to reflect the appropriate ownership level.
Also, the EPA's use of the term "release" can be confusing. While you might assume the word describes the discharge of a chemical into open air or water, it also refers to the careful burial of waste in a permitted landfill.
At the Springerville Generating Station, for example, approximately 94 percent of the chemical "releases" reported on the TRI are associated with coal ash and other combustion residuals that are stored safely in a monitored landfill on-site. That landfill has a thick natural clay liner, an extensive groundwater monitoring system, and is covered by an Aquifer Protection Permit administered by the Arizona Department of Environmental Quality.
As the table below shows, the vast majority of TRI "releases" from facilities that serve TEP customers were impounded in landfills rather than released in air or water. All releases were in accordance with federal, state and local regulations or applicable permits.
As TEP reduces its reliance on coal-fired power, the associated power plant emissions documented by the TRI will decrease accordingly.