Bio Lab Conyers Chemical Release 2020
The investigation concluded that rainwater entered a storage building and reacted with trichloroisocyanuric acid (TCCA), triggering a thermal decomposition that released a massive chlorine gas cloud and forced the closure of a major interstate highway.
On 14 September 2020, the Bio-Lab facility in Conyers, Georgia, experienced a significant chemical reaction and decomposition event. This occurred during a period of heavy rainfall. The facility, which manufactures pool and spa treatment products, was storing large quantities of trichloroisocyanuric acid (TCCA).
The Chemical Safety Board (CSB) determined that the "Causal Factor" was water infiltration. Rainwater entered a warehouse where TCCA was stored in "super sacks." When TCCA comes into contact with small amounts of water, it does not dissolve but instead undergoes an exothermic (heat-producing) chemical reaction. This heat further accelerates the decomposition of the surrounding chemical, releasing toxic and corrosive chlorine gas.
The resulting plume was large enough to be detected miles away. Interstate 20, which runs adjacent to the plant, was closed for approximately six hours as the vapour cloud drifted across the lanes. Nine firefighters who responded to the initial call were exposed to the fumes and required medical evaluation. A second, smaller decomposition event occurred just four days later on 18 September 2020, highlighting the persistent instability of the moisture-damaged chemical stockpiles.
The 2023 final report—which also covered a near-identical disaster at the Bio-Lab facility in Westlake, Louisiana—noted that the company had failed to learn from previous "near-miss" events and lacked adequate roof maintenance and automated moisture detection systems in their chemical storage areas.
Key numbers at a glance
8
Recommendations
31
Months to complete
Cost in millions (if known)
0
Deaths (direct)
Recommendations
Recommendation Category | Summary of Advice | Current Implementation Status |
Roof Integrity | Implement rigorous, documented inspections of all warehouse roofs to prevent leaks. | Implemented (Adopted into site maintenance programmes). |
Moisture Sensing | Install automated moisture and heat sensors in TCCA storage areas. | Implemented (Added to facility safety protocols). |
Reactive Hazards | OSHA to update the Process Safety Management (PSM) rule to include TCCA. | Open – Awaiting Action (Federal agencies still reviewing the PSM list). |
Emergency Response | Improve coordination with local fire departments on handling water-reactive fires. | Implemented (New joint training exercises established). |
Storage Limits | Reduce the height and density of "super sack" stacks to allow for better ventilation. | Implemented (Revised warehousing standards). |
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