Take the Time to PREVENT and PROTECT from Grain Combine Fires

Color photo of a 10 lb ABC fire extinguisher on a grain combine

Grain combines should be equipped with at least two 10-pound ABC fire extinguishers.

The mid-August USDA Wisconsin crop progress report for the 2020 harvest season shows that we will soon be harvesting nearly five million corn and soybean acres in this state–with over 600 million bushels of corn and soybeans being run through combines in a relatively short window of time. During our peak busy period of the year for many farmers, time is super tight as we hurry to complete harvest before the weather begins to transition toward winter. But, it is also crucial that you take the time to avoid a costly and potentially devastating combine fire!

A study of about 9,000 fires completed several years ago confirmed that crop residue is the material most often first involved in a grain combine fire. Our analysis and investigations of burned out machines also showed that more than 75% of fires start in the engine compartment. But fires that cause the most devastation spread rapidly to other areas of the machine. Fires become especially severe when fuel lines rupture from the heat or when a fire burns through a hydraulic hose. These fires become an inferno if the engine is also still pumping out fuel or fluid under pressure. Also, when a combine or tractor fire ignites one or more of the tires (often because the fire burned for too long because of not having a fire extinguisher or because a fire department did not arrive in time) the result is almost always a total loss.

The most critical recommendation is to keep your engine compartment and all other areas clean of all crop residue and any buildup of greasy and oily material. Different machines have different areas in which crop residue will tend to build up. This can vary based on engine design and location, speed and orientation of the engine cooling fan. This can even change a bit from year to year as a result of conditions (wind, relative humidity, and dustiness). With engines located in the rear of a combine, detecting a fire early can be a challenge. Take time to blow out or find other ways to remove any buildup of crop trash daily or as is needed. All fires need an ignition source. Often, exhaust components (turbochargers, manifolds, mufflers) are involved, but faulty bearings or malfunctioning or damaged electrical systems can also be the culprit.

All grain combines need to be equipped with at least two 10-pound ABC dry chemical fire extinguishers. Larger ones are even more preferable, though they are a little more clumsy and require more strength to handle. Avoid new “high tech” and sometimes expensive fire suppression liquids, unless tested and explicitly approved by Underwriter’s Laboratory for dry, cellulosic-type material (crop residue) as well as liquid fuels (diesel fuel, gasoline, hydraulic fluid and motor oil).

ABC Fire Extinguisher

The “ABC” compound means the extinguisher will work on Class A crop residue, Class B flammable liquids, and is non-conductive so it can be used on Class C electrical components.

If you experience a fire, pull away from the standing crop and QUICKLY shut the machine down.  A fire that burns intensely for more than 20 or 30 seconds sometimes can be impossible to put out. Call for help. Use your extinguisher(s) with great care to insure your personal safety and fight the fire by aiming at the base of the flames. Again, the engine must be shut off or air movement will  fan the fire and blow the extinguishing powder out. Air movement will simply mean a hotter fire. Also, if you experience even a small fire that you are able to put out, correct the problem that caused it before you resume and contact your insurance company. 

Harvest is the most dangerous time of the year. Be proactive and careful to protect your safety and your investment!

A pie chart of materials to catch fire in grain combines.

First Material to Catch Fire in 8,927 U.S. Grain Combine (Harvester) Fires







Pie chart of fire origin for grain combine fires.

Fire Origin Location for 8,927 U.S. Grain Combine (Harvester) Fires










Venem, M.T., W. Gilbert and J. Shutske. 2002. Combine Fire Prevention Summit. ASAE Paper No. 028017. St. Joseph, Mich.: ASAE.


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