A weekend fire that sent a massive plume of dark smoke into the Georgia sky has led to complaints about a strong chemical smell and haze several miles away across metro Atlanta, where some schools canceled outdoor activities and others closer to the fire remained stuck at home sheltering from the outdoor air.

More than 90,000 residents east of Atlanta were told to keep sheltering in place Monday, a day after the chemical plant fire.

The haze and chemical smell had spread to Atlanta by Monday morning, prompting firefighters to use detectors to check the air quality in various parts of the city, Mayor Andre Dickens said.

Closer to the source of the fire, officials said chlorine, a harmful irritant, had been detected in the air from the fire at the BioLab plant in Conyers, Georgia, the Rockdale County government said in a statement Monday. The plant is about 25 miles (40 kilometers) southeast of downtown Atlanta.

Who had to evacuate?

People in the northern part of Rockdale County, north of Interstate 20, were ordered to evacuate on Sunday, and others were told to shelter in place.

Sheriff’s office spokesperson Christine Nesbitt did not know the number of people evacuated, although it covered a large portion of the community of Conyers. Media reports said the number was about 17,000.

What should you do if you’re told to shelter in place?

Emergency officials are telling residents near the plant to shelter in place. The best practice is to “turn the air conditioning off and keep windows and doors shut,” Rockdale County officials said.

Emergency management officials in Fulton County, which encompasses much of Atlanta, said people with concerns about the haze or smell should follow the same advice: stay indoors, close their windows and doors and turn off the air conditioning.

Where else are people reporting concerns?

Residents of at least three large counties in metro Atlanta — Fulton, DeKalb and Gwinnett counties — on Monday reported seeing a haze or the strong smell of chlorine.

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In Atlanta, officials believe the hazy conditions and chemical smell is related to the BioLab fire, the Atlanta-Fulton County Emergency Management Agency said in a statement.

Employees were testing the air on Monday for chemicals including chlorine, hydrogen sulfide and carbon monoxide.

Smoke billows from a fire at the BioLab facility in Conyers, Georgia.

Smoke billows from a fire at the BioLab facility in Conyers, Ga., Sunday, Sept. 29, 2024. (Ben Gray/Atlanta Journal-Constitution via AP).

By early Monday afternoon, “no immediate life safety issues have been identified,” Atlanta Fire Rescue reported. Further testing was ongoing. The haze reported by numerous residents Monday morning was “beginning to clear from the city,” the agency said.

Just northeast of Atlanta, the U.S. Environmental Protection Agency had not detected “anything of concern” in Gwinnett County, the county told residents on its social media sites.

In Fayette County southwest of Atlanta, Peachtree City officials advised residents with respiratory issues to shelter in place.

How are schools affected?

Georgia’s largest school system — Gwinnett County Public Schools — initially canceled all outdoor activities and events on Monday. School officials added that they’ve also taken steps to stop outside air from coming into its buildings. Monday afternoon, the school system reversed course, and said that after-school activities could be held.

The DeKalb County School District also announced that no after-school outdoor activities or athletics would take place Monday.

Closer to the scene of the fire, students in Rockdale County Public Schools were already out of the school for a fall break. In nearby Newton County, schools closed Monday, partly because of the large size of the evacuation zone.

What caused the fire?

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.

McDaniel said there were employees inside the plant, but no injuries have been reported, The Atlanta Journal-Constitution reported.

The fire was brought under control around 4 p.m. Sunday, officials said.

What type of manufacturing plant is involved?

BioLab’s website says it is the swimming pool and spa water care division of Lawrenceville, Georgia-based KIK Consumer Products.

The company also said that no injuries were reported.

“Our top priority is ensuring the community’s safety, and our teams are working around-the-clock to respond to the ongoing situation at our facility in Conyers, Georgia,” a spokesperson said in a statement Monday.

“We continue to work collaboratively with first responders and local authorities and have deployed specialized teams from out of state to the site to bolster and support their efforts. We are all focused on remediating the situation as rapidly as possible.”