At 7:47 in the morning on 10 October 2025, the earth shook in Humphreys County, Tennessee. Multiple catastrophic explosions tore through Building 602 at the Accurate Energetic Systems (AES) facility in McEwen. The blast registered as a 1.6-magnitude seismic event. Debris was launched 700 feet. The explosion was felt more than 20 miles away. Sixteen workers were killed.
When the U.S. Chemical Safety Board (CSB) arrived to begin its incident investigation, one of the first things investigators noted was almost too basic to believe: the building where 16 people died — a building containing approximately 24,600 pounds of explosives — had no sprinkler system and no deluge fire suppression.
Process safety management is one of the most complex disciplines in our field. But it is also, at its core, about asking one simple question: if the worst happens here, what is stopping it from becoming a catastrophe? In Building 602, the answer was: nothing.
What Happened at the Accurate Energetic Systems Facility
AES is a commercial explosives manufacturer based in McEwen, Tennessee. On the morning of the incident, workers in Building 602 were manufacturing cast boosters — explosive charges used in mining and demolition operations. The building contained six types of explosive materials: TNT, RDX, PETN, Comp B, Tritonal, and Pentolite. Of the approximately 24,600 pounds of explosives present, around 23,000 pounds were consumed across multiple sequential detonations.
The exact initiating event remains under active investigation by the CSB. However, the scale of the disaster reflects not just a single point of failure but the cumulative effect of a facility where critical safety barriers were either absent or inadequate. The building was razed. Sixteen families lost someone they loved.
“Approximately 24,600 pounds of explosives were in Building 602. The building had no sprinkler or deluge fire protection system.” — U.S. Chemical Safety Board (CSB) investigation update, 2025
Incident Investigation Breakdown: Process Safety Failures at AES
The CSB investigation is ongoing, but the initial investigation update has flagged several critical process safety failures:
Finding — Absence of Fire Suppression Systems: Building 602 had no sprinkler or deluge fire suppression system. In a facility handling energetic materials at this scale, fire suppression is not an optional upgrade — it is a fundamental safety barrier. Its absence eliminated a critical opportunity to interrupt a fire before it reached and initiated the explosive materials.
Investigative Focus — Process Safety Management (PSM) Programme: The CSB is examining AES’s PSM programmes for explosives manufacturing, including how process hazards were identified, assessed, and controlled at each stage of the melt-pour manufacturing process. Effective PSM requires systematic hazard identification — not just compliance documentation.
Investigative Focus — Melt-Pour Process Hazards: The design and operation of the kettles used in manufacturing are under scrutiny. Melt-pour processes for explosive materials involve elevated temperatures and highly energetic molten substances — each step in the process carries potential for uncontrolled initiation.
Investigative Focus — Quantity-Distance and Explosive Segregation: Investigators are reviewing whether the quantities of explosives stored in Building 602, and the arrangement of different explosive types within the same space, were consistent with industry safety guidance on quantity-distance principles and explosive storage segregation.
Lessons Learned: Process Safety Management and Explosive Manufacturing Safety
- Apply Process Safety Management (PSM) principles rigorously in any facility handling energetic, flammable, or reactive materials. PSM is not paperwork — it is the structured identification and control of scenarios where things can go catastrophically wrong.
- Treat fire suppression as a mandatory safety barrier in hazardous occupancies. The presence or absence of a sprinkler or deluge system is the difference between a controlled incident and a mass-casualty event. It is not a cost item to be value-engineered away.
- Apply quantity-distance and segregation principles for explosive inventories. Placing multiple explosive types in the same building multiplies the consequences of any single initiating event and must be assessed in every safety case review.
- Conduct Layer of Protection Analysis (LOPA) for high-hazard manufacturing processes to ensure that independent protective layers exist at every critical control point in the production sequence.
- Engage workers in hazard identification. The people running the kettles, handling the materials, and moving through Building 602 every day often know where the risks are. Build a safety culture where raising concerns is welcomed and acted on.
Cikgu Barrier’s Take: Process Safety Is Not Optional
I want to be direct about something. When a building full of explosives has no fire suppression, that is not a technical oversight. That is a decision, made somewhere in the chain of management and engineering, that the risk was acceptable. And 16 people paid for that decision with their lives.
Process safety exists because some workplace hazards cannot be managed through training and procedures alone. Some hazards require engineered safety barriers — physical defences that work even when people make mistakes, when equipment fails unexpectedly, or when something outside the standard scenario occurs.
The CSB’s investigation will tell us more. But the message every safety officer can deliver today, before the final report: if your facility handles high-hazard materials, audit your protective layers now. Do not wait for a workplace incident to find out where the gaps are.
Follow the CSB investigation updates at csb.gov, and visit Cikgu Barrier at cikgubarrier.com for more on process safety management fundamentals and incident investigation methodology.