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In a recent update, the U.S. Chemical Safety and Hazard Investigation Board (CSB) shared detailed findings on the devastating fire that broke out at BioLab’s Plant 12 storage warehouse in Conyers on September 29. The incident caused significant disruptions, including road closures, hospitalizations, and the evacuation of approximately 17,000 residents due to the ensuing chemical plumes of smoke and toxic vapors.

The CSB’s report reveals that the fire started early in the morning when a BioLab employee, conducting a routine check, heard a 'popping sound.' Upon discovering that the product was wet and showing signs of a reaction, the employee and a colleague attempted to isolate the reacting product but were unsuccessful. By 5:10 a.m., they noticed large plumes of toxic vapor inside the building and promptly called 911.

Despite prior precautionary measures implemented by BioLab, including a permanent fire watch initiated three months earlier due to strong oxidizer odors, the fire erupted significantly. The fire watch was meant to prevent product decomposition and the subsequent release of toxic gases. The two employees on duty were responsible for detecting hazards and managing early signs of product decomposition, among other safety tasks.

The fire became visible through the roof by 6:30 a.m., leading to a shelter-in-place order an hour later. Rockdale fire crews managed to extinguish the initial blaze by 8 a.m., but a second fire flared up around noon, spewing thick black and multicolored smoke visible for miles. This second fire prompted the evacuation of the area and the closure of I-20 for over 30 hours.

The CSB report indicates that Plant 12 housed significant quantities of trichloroisocyanuric acid (TCCA) and sodium dichloroisocyanurate (DCCA), both solid oxidizers known for their volatility. These chemicals can release toxic and corrosive gases, including chlorine and hydrogen chloride, upon decomposition. Additionally, the building stored bromochloro-5,5-dimethylimidazolidine-2,4-dione (BCDMH), which releases similar hazardous gases when it breaks down.

Even after extinguishing the fires, gasses continued to be emitted from residual TCCA trapped beneath the rubble, necessitating heavy equipment for its removal. Local residents within a two-mile radius received nightly shelter-in-place warnings until October 17, attributed to the continued release of dangerous gases.

Environmental impacts extended as smoke drifted towards metro Atlanta, leading to widespread reports of a chlorine smell and haze. Monitoring by the Environmental Protection Agency recorded chlorine levels approximately 20 times above the hourly action level on October 1. Thousands of metro Atlanta residents were subsequently advised to shelter in place.

The aftermath of the fire has already led to several lawsuits, including a federal lawsuit from Rockdale County. Long-term environmental consequences remain uncertain, with the CSB underscoring the significant offsite impacts of the released hazardous substances. The EPA ceased air monitoring on October 17, once concentrations had significantly declined.

BioLab has pledged remediation efforts and opened a claims center in October to address community grievances, though county officials have expressed dissatisfaction with the company's communication. The facility has a history of similar incidents, noteworthy being a 2004 fire that also necessitated mass evacuations and a 2020 chlorine vapor cloud incident.

The CSB continues to investigate the September fire, focusing on the cause of the chemical reactions, storage practices, and emergency response protocols for handling oxidizers. CSB Chairperson Steve Owens emphasized the severity of such incidents, urging all facilities dealing with reactive chemicals to prioritize safety measures. The board's final report will include comprehensive findings and recommendations.