Runaway Reaction Likely Caused Fatal Explosion at Food Color Plant in Ky., Board Says

Materials used in a food-coloring facility in Louisville led to a runaway chemical reaction last November, which likely caused the explosion that killed two workers and seriously injured three others, the U.S. Chemical Safety and Hazard Investigation Board said in an update on the tragedy.

“The results of the chemical reactivity testing show that even within the batch reactor’s normal operating temperature and pressure range, both the caramel coloring ingredient mixture as well as the sugar ingredient alone could experience a hazardous runaway reaction, producing dangerously high temperatures and pressures far beyond the reactor’s safe limits, which in turn could cause the reactor to explode,” the Board’s update report concluded.

The Givaudan Sense Colour facility was producing caramel food coloring in a reactor when the reactor exploded in November 2024. The blast threw large metal pieces of equipment as much as 400 feet away, damaging nearby homes and businesses and prompting a shelter-in-place order for residents.

The sugar used in the process likely was undergoing a decomposition reaction and produced gases that built up pressure in the reactor, the report said.

The plant, which had led to years of complaints from neighbors about the smells emanating from it, has ceased operations and is being demolished.

The update can be seen here. The CSB said the investigation is continuing and a final report will be posted after the review is completed.

Photo: The heavily damaged facility after the explosion. (AP Photo/Dylan Lovan)