A shelter-in-place advisory was extended for a Georgia county Monday after chlorine was detected in the air — a result of a fire at a chemical lab that started Sunday.

A small fire on the plant’s roof was initially contained but reignited Sunday afternoon, authorities said. More than 90,000 residents east of Atlanta were told to keep sheltering in place Monday a day after a chemical plant fire sent a massive plume of dark smoke high into the sky that could been seen for miles.