CSB Completed Investigation - AB Specialty Silicones, LLC - 24 Sept 2021
On May 3, 2019, operators at the AB Specialty Silicones, LLC (AB Specialty) manufacturing facility in Waukegan, Illinois were performing a batch operation that involved manually adding and mixing chemicals in a tank inside the production building. During the operation, an operator pumped an incorrect chemical into the tank, which was incompatible with another chemical that was added to the tank. The incorrect, incompatible chemical was stored in an identical drum to one of the correct chemicals, the only differentiating markings being small labels on the drums, and bung caps.
After the incompatible chemicals were mixed, the tank contents underwent a chemical reaction, causing a process upset in which the tank contents foamed and overflowed from the tank’s top opening. A fog also formed. The CSB determined that the process upset produced hydrogen gas, which released inside the manufacturing facility’s production building. Soon after the hydrogen gas release started, it ignited, causing a massive explosion and fire. The explosion fatally injured four employees destroyed the facility’s production building, and forced the company to cease some and relocate other operations until the production building could be rebuild.
(Source: AB Specialty Silicones, LLC | CSB)