WASHINGTON, DC -- The U.S. Chemical Safety and Hazard Investigation Board (CSB) released an investigation update into the chemical reaction and toxic gas release on September 29, 2024, at the Bio-Lab, Inc. facility in Conyers, Georgia.

The inccident resulted in a massive fire and plume of toxic smoke that threatened the surrounding community and the metropolitan Atlanta area.

The reaction involved materials stored in a warehouse that generated heat, which led to the  decomposition of the product, the release of toxic vapors, and fires.  The primary substances involved in the reaction were trichloroisocyanuric acid (TCCA) and sodium dichloroisocyanurate (DCCA), along with bromochloro-5,5-dimethylimidazolidine-2,4-dione (BCDMH).  The resulting massive plumes of toxic smoke contained chlorine and other hazardous substances and caused significant offsite impacts.  It has been reported that roughly 17,000 people in the surrounding community reportedly evacuated, and nearly 90,000 people in metropolitan Atlanta were advised to shelter in place.   Interstate I-20, which runs parallel to the Bio-Lab facility, was shut down for roughly 18 hours, and smaller roads were closed for even longer.  Nightly shelter-in-place warnings to the surrounding community went on for several weeks after the incident.  Ultimately, the warehouse was completely destroyed.  

CSB Chairperson Steve Owens said, “This incident and the substantial potential risk that it posed to the surrounding community was completely unacceptable.  Reactive chemical incidents can have severe environmental and public safety impacts due to the combination of fire, toxic gas emissions, and hazardous materials involved, and Bio-Lab and any other facility that has reactive chemicals onsite must manage those materials safely.”

The CSB’s update outlines the events surrounding the massive blaze. On September 29, 2024, at 5:00 a.m., a Bio-Lab employee on fire watch in the Plant 12 storage warehouse heard what was reported as a popping sound, which they attributed to wet product. There were no visible flames at that time. After an unsuccessful attempt to isolate the reacting product, the employee called the only other Bio-Lab employee on-site. At approximately 5:10 a.m., the employee called 9-1-1 due to the large hazardous plumes of toxic vapors inside the building. By 6:30 a.m., flames became visible above the area of the chemical reaction and were quickly extinguished in less than two hours.

Emergency responders began evacuations shortly before 12:30 p.m. on September 29, 2024, after a second larger fire broke out at Bio-Lab's Plant 12. This fire was reported extinguished by 4:00 p.m.

Throughout the incident, the Environmental Protection Agency (EPA) conducted air monitoring, finding elevated chlorine and hydrogen chloride levels from September 30th to October 2nd, with the highest levels occurring during night hours.

The CSB is continuing to gather facts and analyze several key areas, including:

The cause of the material decomposition, release of toxic vapors, and fire

Storage and handling of oxidizers and their compatibility

Best practices for responding to emergencies involving bulk solid oxidizer chemical reactions and decompositions

Regulatory and Industry guidance on fire protection systems for bulk solid oxidizers