U.S. Chemical Safety Board Releases Final Report on Fatal 2024 Explosion at Givaudan Facility in Louisville, Kentucky

Washington, D.C. May 27, 2026 - The U.S. Chemical Safety and Hazard Investigation Board (CSB) today released its final investigation report into the fatal November 12, 2024, explosion at the Givaudan Sense Colour caramel coloring manufacturing facility in Louisville, Kentucky, that killed two workers, seriously injured three others, and caused tens of millions of dollars in damage to the facility and the surrounding community.

The CSB determined that the explosion occurred when a 2,500-gallon reactor (Reactor 6) that was producing caramel coloring for a food product experienced a runaway decomposition reaction involving the sugar ingredient being used in the caramel coloring manufacturing process. The resulting rapid pressure increase overwhelmed the reactor's emergency pressure relief system, causing the reactor to rupture violently.

Reactor 6 was constructed in 1978 and was originally operated at a different facility. After that facility closed in 2008, Reactor 6 and another reactor were relocated to the Louisville facility and kept in storage. In 2021, both reactors were modified to meet the Louisville facility's design requirements and were installed in the site's central manufacturing area.

CSB Chairperson Steve Owens said, "This tragic incident was a catastrophe waiting to happen. The reactor's pressure relief system was not designed to release pressure from a reaction like this, and Givaudan did not recognize the potential for a runaway reaction to happen."

The two employees who died in the incident were fatally injured when the blast wave from the explosion damaged the control room where they were working, causing the room to collapse on top of them. The control room was located just 40 feet from Reactor 6 and was not constructed to be blast-resistant. Additionally, the reactor shell, weighing approximately 2,000 pounds, was propelled 245 feet into a nearby residential neighborhood, where it came to rest against a home, and other equipment, materials, and debris from the explosion traveled as far as 400 feet beyond the facility fence line into the surrounding community.

The incident caused approximately $30 million in damage to the facility and an additional $10 million in damage to nearby homes and businesses. Local officials issued a shelter-in-place order covering a one-mile radius around the facility. The facility permanently ceased operations after the incident and recently was demolished.

CSB Supervisory Investigator Lauren Grim said, "The CSB's investigation found that the company did not understand the severe reactive hazards associated with the sugar ingredients used in its caramel coloring process. As a result, critical safeguards, including the emergency relief system, were incapable of preventing this catastrophic reactor rupture."

The CSB found that the reactor's emergency pressure relief system would have needed to be approximately four times larger to safely relieve pressure generated during the runaway decomposition reaction.

CSB Board Member Sylvia Johnson said, "This tragedy demonstrates that companies handling reactive chemical processes must fully understand the hazards of their materials, implement effective safeguards, and ensure that workers and surrounding communities are protected from catastrophic events."

The CSB's final report also emphasizes that companies should conduct facility siting analyses of normally occupied spaces, such as control rooms, and make design changes as appropriate, to protect people and critical equipment from identified process hazards.

The report reiterates earlier recommendations to the EPA and OSHA to strengthen federal oversight of catastrophic reactive chemical hazards. The CSB is recommending again that EPA revise its Accidental Release Prevention Requirements to explicitly address reactive hazards. The CSB also is recommending again that OSHA expand the Process Safety Management (PSM) standard to better address reactive hazards.

The report also issues extensive new recommendations aimed primarily at Givaudan's caramel coloring facilities. These include conducting third-party reactivity testing on sugar ingredients, performing facility hazard analyses, developing comprehensive process safety management systems, improving emergency pressure relief systems, establishing operator alerts, and training on safe operating limits.

Finally, although the CSB is not making a recommendation regarding the siting of a new caramel coloring manufacturing facility elsewhere by Givaudan, the CSB is urging Givaudan to ensure that any new production facility will not be located in close proximity to a residential area in order to help prevent another community from being put at serious risk.

The CSB is an independent, nonregulatory 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 to identify root cause of releases; 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 Director of External Affairs Hillary Cohen at [email protected].