The U.S. Chemical Safety and Hazard Investigation Board has released a second update on its investigation into the September 2024 Bio-Lab fire in Conyers, Georgia.
According to the CSB, the fire began when stored reactive chemicals came into contact with water, triggering decomposition and multiple fires inside the warehouse.
The fire released toxic vapors and smoke, leading to evacuations of about 17,000 residents and shelter-in-place orders that, according to media reports, affected around 90,000 people across the Atlanta area.
The CSB reported that internal corrosion had been documented in the warehouse fire suppression system following the storage of trichloroisocyanuric acid beginning in 2019.
This corrosion reportedly led to repeated sprinkler failures, as seen in facility inspection records obtained by the agency.
The agency has not yet determined how water came into contact with the stored materials but noted the corrosion as a contributing factor under examination.
According to the CSB, Bio-Lab initially planned for the warehouse to store around 6.2 million pounds of oxidizers including TCCA, DCCA, and BCDMH.
By September 2024, the actual volume had increased to roughly 13.9 million pounds, more than twice the stated estimate.
These chemicals were stored in super sacks holding approximately 2,750 pounds each and placed on racks alongside other dry chemicals without segregation.
According to the CSB, a Bio-Lab employee first noticed signs of the fire around 5:00 a.m. on September 29 after hearing a popping sound and detecting heat and smoke.
Emergency responders observed water already flowing from the warehouse upon arrival, suggesting the sprinkler system had activated before their intervention.
By 6:00 a.m., shelter-in-place alerts were issued and evacuations soon followed. A larger fire occurred around noon, and the warehouse began to collapse just after midday.
The U.S. Chemical Safety and Hazard Investigation Board is investigating a September 2024 chemical fire at the Bio-Lab facility in Conyers, Georgia.
The incident was caused by contact between reactive chemicals and water.
The fire led to toxic smoke, evacuations, and shelter-in-place orders across the Atlanta region.
Corrosion in the fire protection system had been noted since 2019.
Bio-Lab had doubled the volume of hazardous chemicals originally planned for storage.
Chemicals were stored in large bags without segregation from other substances.
Sprinklers may have activated before emergency responders arrived.
A second fire and structural collapse occurred later in the day.
The CSB continues to assess contributing factors and safety conditions.
The agency makes safety recommendations but does not issue fines or penalties.
CSB Board members are presidential appointees confirmed by the Senate.
