The TVA announced in August that it planned to spend $1 billion to retrofit the plant with scrubbers that will reduce harmful air pollution by up to 95 percent.
John Suttles is a senior attorney with the Southern Environmental Law Center. He said in a Thursday conference call that the coalition believes TVA's actions violate the National Environmental Policy Act. That act requires federal agencies to take a hard look at the environmental impacts of proposed projects.
TVA said in a statement that the utility did comply with the law and found the plant would have no significant environmental impact.
Copyright 2013 The Associated Press.