Johnston County emergency officials have begun a voluntary evacuation of homes within three miles of a fire that's created smoke and fumes from burning tree stumps.
The county opened a shelter in the new gymnasium at Clayton High School. The communications center initiated reverse 9-1-1 calls about midnight after air monitoring showed heightened levels of carbon monoxide.
Officials advised people who wanted to stay at home to keep windows and doors shut and to turn off their air-conditioning and heating systems to prevent outside air from being drawn inside.
The state Department of Environment and Natural Resources required Stump Dump Incorporated to cover its yard waste with dirt, which representatives say is standard practice. Something caused the fire to combust spontaneously, and officials say the fire started under the dirt before spreading and erupting into a huge cloud of smoke.