NASHVILLE (AP) - A tax break for Tennessee electric cooperatives, enacted by the Legislature in 1988, violates the state constitution, according to an opinion issued last week by Attorney General Herbert Slatery.

Slatery's opinion on the statute was finalized Wednesday, according to multiple media outlets. The statute in question says rural electric cooperatives - which provide electricity to homes and businesses throughout the state via contracts with the Tennessee Valley Authority - are responsible for paying taxes but are exempt from city and county property taxes on new facilities for the first four years of their operation.

Slatery wrote that only certain kinds of properties are exempt from taxes.

"The Tennessee Constitution declares that all property shall be subject to taxation, and it authorizes the General Assembly to exempt only those properties that fall into specific categories. These categories include property owned by s tate and local governments, property held and used for purely religious, charitable, scientific, literary, or educational purposes, and residential property owned by elderly and disabled taxpayers," Slatery said.

The rural electric cooperatives, Slatery said, don't fall within any of those categories.

The Tennessee Electric Cooperative Association had only recently become aware of the exemption and had been working with state officials to take advantage of it, said Association Executive Director David Callis. The co-ops felts obliged to take advantage of any tax break available currently to reduce costs that otherwise must be passed on to electricity consumers, Callis said.

"This attorney general's opinion comes completely out of the blue," he said. "We're still discussing our next steps."