Some residents east of Atlanta were evacuated while others were told to shelter in place Sunday to avoid contaminants from a chemical plant fire that sent a massive plume of dark smoke high into the sky that could be seen from miles away.

Interstate 20 was shut down in both directions in the area, the Georgia Department of Transportation said in a post on X. Reports said traffic was snarled as vehicles backed up in the area after the closure.

The fire ignited when a sprinkler head malfunctioned around 5 a.m. Sunday at the BioLab plant in Conyers, Rockdale County Fire Chief Marian McDaniel told reporters. The malfunction caused water to mix with a water-reactive chemical, producing a plume of chemicals.