OAK RIDGE, Tenn. — Workers have been evacuated from a former uranium enrichment plant in Tennessee after yellow smoke was seen coming out of a ventilation stack.

U.S. Department of Energy spokesman Walter Perry says the smoke was reported about 8:30 a.m. (EST) at a building that processes metal and chemical waste in Oak Ridge, about 20 miles west of Knoxville.

Perry said the department is not asking the public to take any protective action, but workers in surrounding buildings were told to take shelter in place.

No injuries were immediately reported. Firefighters were responding.

The site where uranium for the first atomic bomb was developed has been undergoing cleanup and conversion into an industrial park for several years.