KNOXVILLE, Tenn. (WVLT) - The EPA released its "Toxic 20" Wednesday, and Tennessee once again made the list.

The Toxics Release Inventory ranks states based on residents' exposure to toxic air pollution from coal and oil-fired power plants.

Emissions include pollutants like mercury, hydrochloric acid, sulfuric acid, and ammonia.

The Tennessee Valley Authority helps gather data for the study every year. It says it's working on reducing emissions through a partnership with the EPA.

"We've announced that we're going to install emmissions control equipmen up at our plant in Gallatin, Tennessee, and we're looking at some of our other plants to add controls. And all of this kind of goes back to an agreement we made with the EPA in 2011 to retire about 17 coal fired units," said TVA spokesperson Scott Brooks.

The inventory also lists Alabama, Delaware, Florida, Georgia, Illinois, Kentucky, Maryland, Michigan, Missouri, Mississippi, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia and Wisconsin.