For many firefighters, the phrase “cold storage warehouse” immediately brings to mind one of the most significant tragedies in modern fire service history: the Worcester Cold Storage and Warehouse fire that claimed the lives of six Worcester firefighters in 1999. More than 25 years later, cold storage facilities continue to challenge fire departments across North America, with a recent large-scale incident in Los Angeles demonstrating that these occupancies remain among the most difficult and dangerous structures firefighters encounter.
As food distribution networks expand and online grocery delivery grows, cold storage facilities are becoming larger, taller and more complex. Understanding how these buildings are constructed — and why they burn differently than conventional warehouses — is essential for today’s firefighters.
What is a cold storage warehouse?
A cold storage warehouse is a facility designed to store products at controlled refrigerated or frozen temperatures. These buildings serve:
- Food distribution centers
- Grocery supply chains
- Meat and poultry processors
- Pharmaceutical distributors
- Agricultural operations
- Specialty manufacturing facilities
Modern cold storage facilities commonly exceed 500,000 square feet and may store tens of millions of pounds of frozen products. Inside, crews may encounter high-piled commodities, dense rack systems, extensive plastic packaging and automated storage or retrieval equipment. These features add fire load, limit access to the seat of the fire and complicate suppression in buildings that may look like ordinary warehouses from the outside but behave very differently once involved.
Why cold storage warehouses are built differently
The defining feature of most cold storage facilities is the extensive use of insulated metal panels (IMPs). These panels typically consist of:
- Steel exterior skins
- Foam-plastic insulation cores
- Interlocking seams and joints
The panels form walls, ceilings and sometimes entire compartments within the building. Common insulation materials include:
- Polyurethane foam
- Polyisocyanurate foam
- Expanded polystyrene
- Extruded polystyrene
These materials provide excellent thermal efficiency but can create significant fire loads once involved. For firefighters, the hazard is often hidden behind what appears to be a noncombustible steel surface.
Hidden fire load behind steel walls
One of the most dangerous misconceptions is that metal-faced walls indicate noncombustible construction. In reality, many cold storage facilities contain enormous quantities of combustible insulation hidden behind metal skins.
Once fire breaches a panel system, it can spread through:
- Wall cavities
- Ceiling spaces
- Panel joints
- Pipe penetrations
- Utility chases
Because the fire is often concealed, firefighters may see limited flame involvement while extensive fire spread is occurring behind walls and above ceilings. The result is a structure that can appear tenable while conditions are rapidly deteriorating.
Worcester tragedy
No discussion of cold storage warehouses is complete without examining the Worcester Cold Storage and Warehouse fire.
On Dec. 3, 1999, a fire in an abandoned six-story cold storage building in Worcester, Massachusetts, claimed the lives of six firefighters. The building’s maze-like interior consisted of former meat lockers and storage compartments. Layers of cork, tar, polystyrene foam and polyurethane insulation lined walls and ceilings, creating a massive, concealed fuel package.
Compounding the challenge:
- The building had few windows.
- Interior layouts were confusing and repetitive.
- Visibility deteriorated rapidly.
- Fire spread concealed within insulated assemblies.
- Firefighters entered searching for reported occupants.
Within minutes, crews became disoriented in near-zero visibility conditions and were unable to escape. Six firefighters died after becoming lost inside the structure. The Worcester fire significantly influenced modern fire service thinking on risk assessment, occupant survivability profiling, accountability systems and firefighter rescue operations.
Why cold storage fires burn for days or weeks
In June 2026, a massive cold storage warehouse fire in Los Angeles burned for days, forcing firefighters into defensive operations. Crews were unable to safely enter portions of the building because of structural concerns, roof collapse, extensive steel rack systems and fire concealed within heavily insulated walls and ceilings. Firefighters ultimately removed portions of the building exterior to access hidden fire.
According to fire officials, large building footprints, difficult access, extensive rack storage and limited opportunities to expose concealed spaces also contribute to prolonged suppression operations. Traditional ventilation tactics may be ineffective, and fire can continue spreading despite aggressive suppression efforts.
Smoke conditions
Foam insulation materials generate enormous amounts of smoke when burning.
Potential combustion products include:
- Carbon monoxide
- Hydrogen cyanide
- Nitrogen-containing compounds
- Other toxic decomposition products
Firefighters may encounter:
- Rapid visibility loss
- Extreme heat accumulation
- Toxic atmospheres
- Difficult thermal imaging interpretation
The Worcester incident demonstrated how quickly light smoke conditions can transition to unsurvivable interior environments.
Structural collapse hazards
Many cold storage facilities combine:
- Structural steel
- Tilt-up concrete walls
- Lightweight roof systems
- Rack-supported construction
Fire can attack structural components while remaining hidden behind insulation. Warning signs may be difficult to recognize because firefighters cannot always observe the actual seat of the fire. When extensive concealed fire is suspected, incident commanders should continuously reevaluate whether offensive operations remain appropriate.
Ammonia refrigeration systems
Many cold storage facilities rely on industrial ammonia refrigeration systems. Anhydrous ammonia presents multiple hazards:
- Toxic inhalation exposure
- Respiratory injury
- Corrosive effects
- Potential flammability under certain conditions
During the Los Angeles cold storage fire, firefighters were forced to alter operations after concerns arose regarding a compromised ammonia system and hazardous gas release. Hazmat resources became a critical component of the incident.
While ammonia remains common in large industrial refrigeration systems, some newer facilities utilize carbon dioxide, synthetic refrigerants or hybrid systems. Preplanning should identify the specific refrigeration technology used in each facility, as hazards and emergency procedures may differ.
Solar arrays and energy storage systems
Many newer logistics and cold storage facilities feature new hazards:
- Rooftop solar installations
- Large electrical systems
- Battery energy storage systems
- Automated warehouse technologies
The Los Angeles incident highlighted concerns about rooftop solar infrastructure and the possibility of lithium-ion energy storage systems complicating suppression efforts. These systems add electrical hazards and can complicate ventilation, roof operations and overhaul.
Complex fire protection systems
Modern cold storage warehouses are typically protected by specialized automatic sprinkler systems designed for freezer and refrigerated environments. However, concealed fires within insulated wall and roof assemblies may continue to spread outside the reach of sprinkler protection. Firefighters should understand the facility’s sprinkler design, water supply requirements and system limitations during preplanning.
Preplanning cold storage facilities
Cold storage occupancies should be considered high-priority preplans. Company officers should identify:
Construction features
- Insulation type
- Panel construction
- Roof assemblies
- Void spaces
Fire protection systems
- Sprinkler design
- Water supply demands
- Fire department connections
- Control valves
Refrigeration hazards
- Ammonia system locations
- Shutoff procedures
- Machinery rooms
- Monitoring systems
Building access
- Travel distances
- Stairwells
- Loading dock access
- Roof access points
The more information firefighters gather before an incident, the fewer surprises they will encounter when conditions deteriorate.
Practical takeaways for firefighters
While every facility presents unique risks, several operational principles consistently emerge from line-of-duty death investigations, large-loss fires and after-action reports. Understanding these lessons can help firefighters recognize warning signs, make informed tactical decisions and better manage the risks associated with these complex structures.
FireRescue1 is using generative AI to create some content that is edited and fact-checked by our editors.
