KNOXVILLE, Tenn. (AP) — The Tennessee Valley Authority says it is investigating after a noose was found at the Browns Ferry Nuclear Plant in Alabama.

A spokesman for the nation’s largest public utility, Travis Brickey, said he didn’t know if investigators considered the incident racially motivated. He also said he couldn’t give further details after the discovery at the plant near Athens, Ala.

The Knoxville News Sentinel reported it was the fifth time a noose has been reported near or at a TVA facility in four years.

In an employee newsletter, TVA President and Chief Executive Officer Tom Kilgore praised those who reported the noose to authorities and promised a full investigation.

“While this appears to be an isolated incident, it is serious and wil not be tolerated,” Kilgore said in a statement in the newsletter.

The utility said the agency’s Office of Inspector General was investigating.

In a 2009 report, TVA’s Office of the Inspector General described two incidents involving nooses at the Shawnee Fossil Plant near Paducah, Ky.

In one, a supervisor noticed a noose in a photograph of scaffolding, the report indicated. In another, a unit operator tied a noose in view of an African-American employee. The report does not note the race of the person tying the noose. It said he untied the noose and apologized after being told by another worker that his behavior could cost him his job.

And In September 2008, a hangman’s noose was found at Tennessee’s Kingston Fossil Plant. While this was being investigated, another noose was found hanging 30 feet up on a steel structure outside the plant, and investigators said the noose had been there for years.

Copyright 2012 The Associated Press.