CSB Releases Update on Investigation of Explosion at Kentucky Coloring Facility

A vent valve is the focus of an investigation into the November 2024 explosion at a Louisville facility that produces coloring for the food and beverage industry, according to an update released by the U.S. Chemical Safety and Hazard Investigation Board (CSB). The explosion on Nov. 12, 2024, killed two workers of Givaudan Sense Colour, seriously injured three others, damaged property on and around the site, and led to a shelter-in-place order for residents within a one-mile radius.

Problems began soon after operators at the facility, following instructions, adjusted pressure and temperature setpoints in the batch reactor. Within 30 minutes, the pressure exceeded the setpoint of 12 pounds per square inch and continued to rise. According to CSB, the reactor ruptured after pressure reached 237 psi, three times the allowable limit for the reactor, and the temperature reached 385 F, well above the allowable limit of 355 F.

The vent valve was supposed to open automatically to maintain a pressure of 12 psi within the reactor. But after the incident, the valve was found to be almost fully closed. In addition to focusing on the recovered valve, CSB’s investigation will test the raw materials to identify potential reactive hazards, analyze the batch reactor relief system, and evaluate emergency response efforts.

Local news reports indicated that the facility was in the residential Clifton area of Louisville.

For more information, read CSB’s news release.