The group announced its findings yesterday on the cusp of a US senate vote regarding the Environmental Protection Agency’s authoritative scope in controlling mercury and other toxic air pollutants.

The report found the 25 most polluting power plants around the Great Lakes were accountable for more than half of the 13,000 pounds of mercury which was pumped into the region’s air in 2010.

There are more than 144 coal-fired power plants in the eight states bordering the Great Lakes.

The NRDC said these states contained almost a quarter of the nation’s mercury pollution.

Ohio emits the largest amount of mercury from coal-fired power plants (21% of the total in the Great Lakes region), followed closely by Pennsylvania (20%) and Indiana (16%).

The report listed the five worst coal-fired power plants for mercury pollution as Shawville (Clearfield County, PA); Monroe (Monroe County, Michigan); Homer City (Indiana County, PA); Cardinal (Jefferson County, OH) and Sherburne County (Sherburne County, Minnesota).

Ohio-based utility American Electric Power was singled out for owning in part or in whole 12 plants which caused 19% of all mercury emitted in the region in 2010.

The NRDC also noted almost 90% of the toxic emissions could be eliminated with “off-the-shelf” technologies.