CSB Investigation — Explosion & Fire
Givaudan Sense Colour Explosion
Givaudan Sense Colour / D.D. Williamson
📍 Louisville, KY
Incident Date: November 12, 2024  |  CSB Report Released: May 27, 2026
2
Fatalities
2
Injuries
Runaway Reaction
Sugar Decomp.
Chemical / Hazard
8
CSB Recommendations
📋 Incident Summary

On November 12, 2024, Reactor 6 at the Givaudan Sense Colour (formerly D.D. Williamson) caramel coloring facility in Louisville, Kentucky ruptured catastrophically. A runaway thermal decomposition reaction of sugar ingredients — invert sugar and corn syrup — generated enormous pressure that overwhelmed the vessel. The explosion killed two workers, seriously injured two others, and ejected a section of the pressure vessel beyond the fence line into a neighboring residential unit.

The facility produced caramel coloring by heating sugar ingredients under high temperature and pressure. What engineers and management did not know — because they had never tested it — was that these sugars decompose exothermically at elevated temperatures, generating CO₂ gas and heat that can rapidly overpressurize a closed vessel. No calorimetry had ever been performed on the process materials. No PSM program existed. Reactor 6 had no pressure relief system sized for the decomposition scenario.

The CSB's final report (released May 27, 2026) identified a complete absence of Process Safety Management as the systemic cause. Eight recommendations were issued, all targeting reactive chemistry characterization, PSM system development, adequate relief design, and safe operating limit alarm systems.

🔎 Key Findings
Finding 1
Unknown Reactive Hazard
No calorimetry or reactivity testing had ever been performed on the sugar ingredients. The decomposition temperature, pressure behavior, and gas products of invert sugar and corn syrup were unknown to facility management and engineers.
Finding 2
Inadequate Pressure Relief System
Reactor 6's pressure relief was not designed for a decomposition reaction scenario — because that scenario had never been identified. Relief systems sized only for routine overpressure cannot handle runaway reaction events.
Finding 3
No Process Safety Management System
The facility operated with no formal PSM program — no Process Hazard Analysis, no formally defined Safe Operating Limits, and no alarm systems to alert operators when limits were approached.
Finding 4
No Facility Siting Study
Workers and adjacent residential units were within the blast radius of a catastrophic vessel failure. No siting study had been conducted to quantify the blast zone or assess community risk.
Finding 5
No Corporate PSM Leadership
Givaudan's corporate structure had no senior leader accountable for process safety at caramel coloring facilities. The safety gap at Louisville reflected a systemic corporate governance failure.
Finding 6
Community Impact
A section of the ruptured pressure vessel landed in a neighboring residential complex — a direct consequence of inadequate facility siting and uncontrolled explosion energy in a process with no hazard management framework.
🔍 Root Causes
1
Uncharacterized Reactive Chemistry
The thermal decomposition of sugar ingredients at process temperatures was never measured. Operating without reactive hazard data means the facility had no way to know its own worst-case scenario.
2
Absent PSM Framework
No PHA existed to identify reactive hazard scenarios. Without structured hazard identification, the gap in chemistry knowledge was never caught — and was invisible to management.
3
Relief System Designed for Wrong Scenario
Pressure relief was sized for routine overpressure, not for a runaway decomposition reaction. Without calorimetry data, you cannot design adequate relief systems — and without a PHA, you may not even know you need them.
4
No Safe Operating Limit Alarms
Operators had no automated alert when process conditions approached the danger zone. Human vigilance alone is never an adequate safeguard against runaway reactions.
5
Corporate Governance Gap
No senior corporate leader was accountable for PSM across caramel coloring operations. Without corporate-level ownership, facility-level gaps persist indefinitely.
☑ CSB Recommendations
→ Givaudan Caramel Coloring Facilities
Conduct calorimetry testing on all sugar ingredient recipes to determine decomposition temperature, pressure behavior, and gas products. Maintain this data for equipment design and hazard analyses.
→ Givaudan Caramel Coloring Facilities
Conduct third-party hazard analysis at each caramel coloring facility, incorporating the calorimetry data required above.
→ Givaudan Caramel Coloring Facilities
Develop a formal Process Safety Management system at each facility aligned with CCPS Guidelines for Risk-Based Process Safety.
→ Givaudan Caramel Coloring Facilities
Contract a third party to design adequate emergency pressure relief systems using the calorimetry data. Document each vessel's relief design basis.
→ Givaudan Caramel Coloring Facilities
Establish automatic safe operating limit alarms and train operators on limits and required responses.
→ Givaudan Caramel Coloring Facilities
Conduct a facility siting study before constructing new caramel coloring facilities to protect workers and community.
→ Givaudan Corporate
Create a senior corporate leadership position responsible for PSM oversight at all Givaudan caramel coloring facilities.
→ ITCA / Corn Refiners Assoc. / Intl Molasses Corp
Issue safety bulletins alerting industry to the Givaudan incident. Update SDS documents for sugar ingredients to include decomposition temperature, consequences, and gas products.
💡 Lessons Learned
⚠ You cannot protect against a hazard you have not identified. Reactive chemistry screening and calorimetry testing are non-negotiable for any thermal process.
⚠ Pressure relief systems must be sized for the worst-case scenario — including runaway reactions. Without reactive hazard data, relief system design is guesswork.
⚠ Process Hazard Analysis exists precisely to catch hazards before they become incidents. If your facility has no PHA, it has no systematic hazard identification.
⚠ Safe Operating Limits are not meaningful unless operators are alerted before those limits are exceeded. Alarms are required safeguards, not optional enhancements.
⚠ Facility siting studies protect workers and the community. Any facility with explosion potential must quantify its hazard footprint and verify that occupied areas are outside the blast radius.
PSM Elements: PSI · PHA · MI · SOP · EP
🔨 Safety Meeting Toolbox Talk
Topic: Reactive Chemical Hazards & Process Hazard Analysis
💬Does our process involve any chemicals or reactions that can generate heat, pressure, or gas if temperature or pressure limits are exceeded?
💬Have we conducted calorimetry or reactive hazard screening on our process materials? Do we know our decomposition temperature?
💬Are our pressure relief systems designed for the worst-case scenario — including any runaway reaction event — or only for routine overpressure?
💬Do we have alarms that alert operators BEFORE safe operating limits are exceeded, while there is still time to take corrective action?
💬When did we last conduct a Process Hazard Analysis on our process? Were reactive hazards and thermal runaway specifically evaluated?
💬Have we conducted a facility siting study? Do we know whether adjacent occupied areas are within our worst-case hazard zone?
✎ Team Action Items
✓Request and review the most recent Process Hazard Analysis for your unit — specifically look for reactive chemistry and overpressure scenarios
✓Verify that pressure relief devices on any reactor or heated pressure vessel have documented design basis that covers all identified scenarios
✓Confirm that safe operating limit alarms are tested and functional for all thermal processes in your facility
✓Ask your safety manager whether reactivity testing has ever been performed on your process chemicals — if not, flag it as a gap
🔗 PSM Failures Behind This Incident

This incident traced to breakdowns across 5 PSM elements (PSI · PHA · MI · SOP · EP). Each represents a documented gap that process safety documentation and consulting can close before a similar event occurs at your facility.

Process Safety Information (PSI)
Accurate, complete Process Safety Information is the foundation every other PSM element depends on. When PSI is missing or wrong — chemistry data, equipment specs, P&IDs — the entire hazard analysis is built on a flawed base.
Supporting documents in our library →
Process Hazard Analysis (PHA)
A structured PHA or HAZOP study exists to identify exactly these scenarios before they occur. When PHA is absent, superficial, or overdue for revalidation, hazards operate unseen until they kill someone.
Supporting documents in our library →
Mechanical Integrity (MI)
Equipment must be designed, inspected, and maintained to operate safely in its intended service. Mechanical integrity failures — degraded equipment, missed inspections, deferred repairs — contributed to loss of containment here.
Supporting documents in our library →
Operating Procedures (SOPs)
Operators cannot reliably hold safe operating limits without clear, current, enforced procedures. Deviation from acceptable operating conditions — a root cause here — is a direct consequence of SOP failure.
Supporting documents in our library →
Employee Participation
OSHA PSM requires workers to be meaningfully involved in hazard analyses and procedure development — not just trained on the finished product. Active participation catches gaps that management alone misses.
Supporting documents in our library →
Process Safety Management Consulting & Document Library
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