Louisville, KY — A catastrophic explosion at a food coloring manufacturing facility in Louisville, Kentucky has claimed the lives of two workers and left three others with severe injuries, according to a new report from the U.S. Chemical Safety Board (CSB). The incident, which occurred on November 12, 2024, also inflicted significant damage to surrounding homes and businesses, propelling debris up to 400 feet away from the site.
The CSB investigation is scrutinizing the events leading up to the explosion, which began during a routine operation to produce caramel coloring using a batch reactor. The process appeared normal until midafternoon when the internal pressure unexpectedly surged beyond safe limits, ultimately causing the reactor to rupture violently.
Steve Owens, CSB Chairperson, expressed grave concerns about the blast, emphasizing the preventable nature of the tragedy. “This massive explosion should not have happened,” Owens stated. “Two people lost their lives, numerous homes and businesses were heavily damaged, and the community was placed in grave danger.”
On the day of the disaster, facility operators adjusted the reactor’s pressure to 12 pounds per square inch gauge (psig) and set the temperature at 300 degrees Fahrenheit, per the production instructions. However, by 14:39, the pressure had exceeded these settings. Efforts to decrease the pressure failed and, after briefly opening, the pressure relief valve was unable to prevent the pressure and temperature from continuing to rise—reaching a perilous 385°F, well over the reactor’s maximum allowable temperature.
At 14:57, when the internal pressure hit an overwhelming 237 psig—more than double the intended maximum—the reactor failed catastrophically. Investigations later revealed that the reactor vessel’s automated vent valve, which should have opened to relieve pressure, was nearly closed.
In response to the findings, the CSB has planned an extensive review of the incident encompassing tests on raw materials for potential reactive hazards, analysis of the reactor’s pressure relief systems, and a detailed look at the process conditions and data leading up to the explosion.
Further scrutiny will focus on the malfunctioning vent valve and actuator to determine whether mechanical failure or operational errors were at fault. In addition, the effectiveness of the emergency response to the incident will undergo evaluation to improve safety protocols for future emergencies.
Local authorities had initially issued a shelter-in-place order covering a one-mile radius around the site immediately following the explosion, underscoring the severity of the risk to the neighborhood.
As the community begins to recover from the physical and emotional toll of this disaster, the CSB’s ongoing investigation aims to uncover the root causes of the explosion to prevent similar incidents in the future. The final results of this thorough inquiry are eagerly awaited by all who were affected by the tragic events of last November.