NASHVILLE (AP) — The Sierra Club has filed a lawsuit against the Tennessee Valley Authority over a Freedom of Information Act request for documents relating to the utility's plan to spend nearly $1 billion to reduce emissions at its coal-fired plant in Gallatin.

The lawsuit filed in federal court in Washington, D.C., earlier this month also asks for an injunction to extend a public comment period on the draft environmental assessment of a plan to upgrade the plant to meet new federal clean-air standards.

TVA provided a partial response of more than 800 electronic files and extended the comment period for two weeks, which ends Friday.

TVA attorneys called the lawsuit premature because the Sierra Club did not seek expedited processing of its records requests until Oct. 23, months after the original requests were made in April, May and June.

The Sierra Club argued that the partial records provided by TVA left out important information that it needs for members who want to make a public comment. The group is planning an online advertising campaign advocating that the plant should be phased out in favor of energy efficiency.