Atlanta residents report chemical odor from Conyers Plant fire.

A shelter-in-place order for all of Georgia’s Rockdale County has been extended indefinitely, authorities announced Monday morning after a fire at the BioLab plant.

The presence of chlorine has been confirmed by Federal EPA and state EPD testing, according to a spokesperson for Rockdale County. What, if any, other chemicals might be involved has not been detailed yet.

According to an official alert sent out by text to residents by the Georgia Emergency Management Agency, “LOCAL AREA EMERGENCY due to ROCKDALE COUNTY BIOLAB FIRE. The EPA is MONITORING air quality for CHLORINE AND RELATED COMPOUNDS. Chemical levels are UNLIKELY TO CAUSE HARM TO MOST PEOPLE.”

Here’s what we know so far:

A fire at a chemical plant in Rockdale County sent a colossal plume of smoke into the sky Sunday as onlookers shared photos and videos of the scene to social media.

The fire at BioLab, a chemical facility on Old Covington Road in Conyers, led to the evacuation order of about 17,000 people and several road closures, including I-20, on Sunday afternoon. The interstate reopened by Monday morning, but several roads remain closed, and the smoke — now a chemical reaction and not a fire — will remain visible for several days.

On Sunday and well into Monday morning, the massive plume was visible from Hartsfield-Jackson International Airport — about 30 miles away.

Authorities have not given word yet on what other chemical compounds could potentially be present in the smoke now emanating from the scene, or what effect the toxins could have on other areas downwind from Rockdale County.

The shelter-in-place order remains in effect for all of Rockdale County, which has a population of just over 90,000, according to the 2020 census. It is not clear when that order will lift.

“In the best interest and safety of the public and all citizens, it is recommended that businesses close operations until shelter-in-place is lifted,” county officials said Monday. " For everyone sheltering in place, the best practice is to turn the air conditioning off and keep windows and doors shut.”

So far, air quality tests have been within “acceptable levels,” the Atlanta Fire Rescue Department said Monday afternoon.

Officials in Fulton and Gwinnett counties also reported hazy skies and a strong chemical odor Monday.

In Gwinnett, the U.S. Environmental Protection Agency is recommending anyone in the direct plume to stay inside but has not recommended a shelter-in-place order for the county.

What caused the fire?

It is unclear yet what sparked the fire, which started on the facility’s roof sometime Sunday morning. It was initially extinguished but reignited later that afternoon, triggering the building’s sprinkler system, which then caused water to mix with a water-reactive chemical.

Workers had already been trying to move the chemical away from the water source, but weren’t able to finish doing so by the time the sprinkler system was activated.

The flames were brought under control by 4 p.m. EST, and the plant’s roof and walls have since collapsed. No injuries were reported, though some employees were inside the plant at the time.

According to the company’s website, BioLab “is the swimming pool and spa water care division of KIK Consumer Products.” That company is based in nearby Lawrenceville.

Has this happened before?

Rockdale County fire Chief Marian McDaniel said it was the third such incident of “this magnitude” at the plant in at least seven years.

In September 2020, a “TCCA reaction and decomposition” caused another plume of hazardous chemicals to be released into the air at the Conyers plant, exposing facility personnel and nine firefighters to “dangerous fumes,” according to a U.S. Chemical Safety and Hazard Investigation Board report. Surrounding businesses were evacuated and a section of I-20 was closed for about six hours.

The report stated another decomposition involving TCCA happened four days later at the plant, but no one was injured.

“TCCA is used throughout the country in pool care and, when put in large bodies of water such as a pool, breaks down slowly, releasing chlorine in the water,” the report added. “However, when TCCA comes into contact with small amounts of water and does not dissolve, it can undergo a chemical reaction that generates heat, causing the decomposition of TCCA, which produces toxic chlorine gas.”

It is not clear if the same chemical was involved in Sunday’s incident.