When restaurant owners hear numbers like “over 100 pounds of grease,” it can be hard to visualize what that actually means. In this Los Angeles restaurant, the kitchen exhaust system had not received a proper, full cleaning in several years. What appeared on the surface to be a functioning system was, in reality, heavily contaminated from the hood all the way through the ductwork and exhaust fan.
By the time the system was finally accessed and cleaned, more than 100 pounds of grease had been removed. This was not grease from one small section. It was accumulated throughout the exhaust system, hidden above ceilings and inside ducts where it had gone unseen for years.
This article explains, in simple and easy language, how grease can build up to this extreme level, why restaurant owners often have no idea it is happening, what risks this amount of grease creates, and how proper exhaust cleaning prevents situations like this. There is no technical jargon and no complicated explanations—just clear information based on real conditions found in the field.
This restaurant kitchen exhaust system in Los Angeles had not had a proper cleaning in several years. We ended up cleaning over 100 pounds of grease from it.
How Grease Accumulates Inside an Exhaust System
Every time cooking equipment is used, grease vapors rise into the exhaust hood. Filters capture some of this grease, but not all of it. A portion passes through and enters the duct system.
As grease-laden air moves upward, it cools. When it cools, grease condenses and sticks to the metal surfaces inside the duct. This process happens every day, during every cooking shift.
If the grease is not removed regularly and thoroughly, it remains inside the system. Over months and years, layer after layer builds up. What starts as a thin coating slowly becomes thick, heavy accumulation.
Why This Can Happen Without Anyone Noticing
One of the most surprising things for restaurant owners is how much grease can accumulate without any obvious warning signs.
From the kitchen floor, everything may appear normal. The hood may look clean. Air may still be moving. The restaurant may operate for years without visible problems.
The reason is simple: most of the exhaust system is hidden. Ductwork runs above ceilings and inside walls. Exhaust fans sit on the roof. Unless these areas are accessed and inspected, grease buildup remains invisible.
This is how a system can quietly accumulate over 100 pounds of grease.
What “Over 100 Pounds of Grease” Really Means
One hundred pounds of grease is not a small amount spread thinly. It represents thick, heavy buildup coating large sections of the exhaust system.
In systems like this, grease is often found:
- Lining the interior of ducts
- Pooling at the bottom of horizontal runs
This level of accumulation usually means the system has been partially cleaned or surface-cleaned for years, while hidden areas were ignored.
Table: Where Large Amounts of Grease Are Typically Found
| Exhaust System Area | Typical Condition | Why It’s Dangerous |
| Duct above the hood | Thick grease layers | High ignition risk |
| Horizontal duct runs | Grease pooling | Heavy fuel source |
| Duct elbows | Hardened buildup | Fire spread point |
| Exhaust fan housing | Grease-coated components | Roof fire risk |
This table reflects common findings in severely neglected systems.
Why This Much Grease Is a Serious Fire Hazard
Grease inside an exhaust system is fuel. When over 100 pounds of grease is present, the system contains a massive amount of combustible material.
If flames or high heat enter the exhaust system, they can ignite this grease quickly. Once ignition occurs, fire can travel through ductwork and into concealed spaces.
Exhaust fires fueled by heavy grease buildup are difficult to control and often spread beyond the kitchen. This is why fire codes focus so heavily on keeping exhaust systems free of grease.
Why Cleaning Schedules Alone Often Fail
Many owners assume that being on a cleaning schedule prevents severe buildup. Unfortunately, schedules only work if the cleaning is thorough.
In many cases, cleanings focus on visible areas like the hood and filters. Hard-to-reach sections of ductwork may be skipped or only partially cleaned.
When this happens repeatedly over years, grease accumulates silently. The system is technically “serviced,” but not truly clean.
This is how systems reach extreme levels of contamination.
Why This Situation Took Years to Develop
Grease does not reach 100 pounds overnight. This level of buildup typically takes several years of neglect or incomplete cleaning.
Each missed area adds a little more grease. Each incomplete cleaning leaves behind residue. Over time, these small failures compound.
By the time the problem is discovered, the system is far beyond what routine maintenance can handle.
The Cost of Letting Grease Reach This Level
Severely contaminated exhaust systems are more expensive and more dangerous to clean.
Heavy grease is harder to remove and may require special procedures. There is also increased risk to the building, equipment, and workers.
In addition, systems with this level of contamination are far more likely to fail inspections or become involved in fires.
Preventive cleaning costs far less than addressing extreme neglect.
Why Owners Are Often Shocked by the Findings
When owners see the amount of grease removed from their system, the reaction is often disbelief.
Many believe their system was being cleaned properly because service visits occurred regularly. Seeing piles of removed grease challenges that assumption.
This moment of realization is common—and it highlights why visibility and verification are so important.
How Inspections Prevent Extreme Buildup
Inspections are designed to catch problems before they become severe. When access doors are opened and duct interiors are checked, grease buildup is identified early.
Early detection allows for targeted cleaning before grease hardens and accumulates in large quantities.
Regular inspections combined with thorough cleaning prevent systems from ever reaching this condition.
What Restaurant Owners Can Do
Owners do not need to inspect ducts themselves. What they do need is awareness.
Understanding that grease can quietly build up to extreme levels helps owners ask better questions. Requesting inspection photos and confirmation that all duct sections are being cleaned makes a significant difference.
Owners who stay informed are far less likely to face shocking discoveries.
How Bryan Exhaust Handles Severe Grease Buildup
Bryan Exhaust specializes in addressing heavily contaminated exhaust systems. Our approach includes full access to duct interiors, removal of hardened grease, and verification that all areas are properly cleaned.
By restoring systems to a safe condition, we help owners reduce fire risk and regain control over their exhaust maintenance.
Final Thoughts
Removing over 100 pounds of grease from a restaurant kitchen exhaust system is a clear sign of long-term neglect or incomplete cleaning.
This situation did not develop suddenly, and it was not unavoidable. It was the result of grease being allowed to remain inside the system year after year.
Proper, thorough exhaust cleaning prevents grease from ever reaching this level. Visibility, inspection, and full-system access are the keys to keeping exhaust systems safe and compliant.
