Louisville, Kentucky – The U.S. Chemical Safety Board has recently unveiled its conclusive investigation report on the devastating explosion that took place at the Givaudan facility in Louisville last November. The blast resulted in the tragic loss of two employees and left several others injured. The report sheds light on the critical moment when the pressure within a batch reactor exceeded safe levels, leading to its rupture. An investigation revealed that an automated vent valve malfunctioned, failing to open as intended, ultimately triggering the explosion.
According to the detailed timeline outlined in the report, the incident began at 10:22 a.m. when operators initiated the production of a caramel coloring food product. By 2:17 p.m., the pressure in the batch reactor had been adjusted to 12 pounds per square inch gauge (psig), with the temperature setpoint at 300°F as per the batch instruction. However, by 2:39 p.m., the pressure in the reactor surpassed the setpoint, despite efforts to lower it, resulting in a continuous rise in pressure.
At 2:54 p.m., the pressure relief valve was opened, causing a temporary decrease in pressure before it began escalating again. The temperature inside the reactor soared beyond the setpoint, reaching 385°F, surpassing the allowable limit of 355°F by 30 degrees. The catastrophic rupture of the reactor occurred at 2:57 p.m. when the pressure hit 237 pounds per square inch gauge, well over three times the maximum allowable pressure of the reactor.
The failure of the automated vent valve to open and relieve pressure in the vessel at the designated setpoint was identified as the primary cause of the explosion. The CSB has committed to further examining the recovered vent valve and actuator as part of its ongoing investigation to prevent similar incidents in the future.
In addition to the human toll, the explosion resulted in debris being ejected beyond the facility’s perimeter, with some remnants flying up to 400 feet into the nearby Clifton neighborhood. CSB Chair Steve Owens emphasized the preventable nature of the disaster, stressing the need for enhanced safety measures to protect lives and properties in industrial settings.
Moving forward, the CSB’s investigative roadmap includes rigorous testing of raw materials to identify potential reactive hazards, comprehensive analysis of the batch reactor relief system, review of process data leading to the incident, in-depth evaluation of the vent valve and actuator, and a thorough assessment of emergency response protocols. These measures aim to enhance safety practices and prevent similar tragedies from occurring in the future.