Washington D.C. February 27, 2025 – Today the U.S. Chemical Safety Board and Hazard Investigation Board (CSB) released an update into its ongoing investigation into the fatal November 12, 2024, explosion at the Givaudan Sense Colour facility in Louisville, Kentucky. The incident killed two employees and seriously injured three others. The explosion caused significant property damage to the facility and nearby homes and businesses. Debris was ejected outside the facility's fence line, flying up to 400 feet into the nearby neighborhood, and local authorities issued a shelter-in-place order for a one-mile radius around the facility.
CSB Chairperson Steve Owens said, “This massive explosion should not have happened. Two people died, homes and businesses were severely damaged, and the neighboring community was put at serious risk.”
At 10:22 a.m. on the day of the incident, operators at the facility began a process to produce caramel coloring for a food product in a batch reactor. Operations were normal initially. At 2:17 p.m., the pressure setpoint for the batch reactor was adjusted to 12 pounds per square inch gauge (psig), and the temperature setpoint was set to 300 degrees Fahrenheit (°F), as specified in the batch instruction. By 2:39 p.m., however, the pressure in the reactor exceeded the setpoint, and despite attempts to reduce it, the pressure continued to rise. After the pressure relief valve opened at 2:54 p.m., the pressure initially decreased, but then it continued to climb. The temperature also increased far above the setpoint, reaching 385°F, which was 85 degrees above the setpoint and fully 30 degrees above the reactor’s allowable limit of 355°F. A few minutes later, at 2:57 p.m., the reactor catastrophically ruptured when the pressure in the reactor reached 237 psig, over three times the reactor’s maximum allowable pressure.
After the incident, it was discovered that the reactor vessel’s automated vent valve was almost fully closed. The vent valve was supposed to automatically open to relieve pressure in the vessel to maintain the pressure at the 12 psig setpoint. As part of its ongoing investigation, the CSB will further inspect the recovered vent valve and actuator.
The CSB’s update outlines the investigation’s path forward, which will include:
- Testing the raw materials to identify potential reactive hazards
- Analyzing the batch reactor relief system
- Reviewing process data and process conditions leading to the incident
- Further analyzing the recovered vent valve and actuator
- Evaluating emergency response efforts
The CSB is an independent federal agency charged with investigating incidents and hazards that result, or may result, in the catastrophic release of extremely hazardous substances. The agency’s core mission activities include conducting incident investigations; formulating preventive or mitigative recommendations based on investigation findings and advocating for their implementation; issuing reports containing the findings, conclusions, and recommendations arising from incident investigations; and conducting studies on chemical hazards.
The agency's board members are appointed by the president subject to Senate confirmation. The Board does not issue citations or fines but makes safety recommendations to companies, industry organizations, labor groups, and regulatory agencies such as OSHA and EPA.
Please visit our website, www.csb.gov. For more information, contact Communications Manager Hillary Cohen at [email protected].