Corn Silage Harvest Safety Should Be Priority One

Jason Hartschuh, Extension Educator, Agriculture and Natural Resources, Crawford County and Chris Zoller, Extension Educator, Agriculture and Natural Resources, Tuscarawas County

Corn silage harvest is a busy time of year, with the quality of corn silage determining your ability to produce milk for the next year. During this busy time of year, safety is critical with equipment moving all over the farm and harvest causing many long days and short nights.  

Hazards of Silo/Bag/Bunker Gases

While silo gases are the most dangerous, these same gases are trapped in closed bags and bunkers during fermentation. These deadly gases, nitrogen dioxide and carbon dioxide, are a natural result of ensiling. Nitrogen dioxide is heavier than air and may be seen as a reddish to yellowish-brown haze. Since it is heavier than air, it can be found near the base of a recently filled silo. It has a bleach-like smell, and you will experience a burning sensation in your nose, throat, and chest. Instant death may result from nitrogen dioxide inhalation.

Carbon dioxide fills the headspace of the silo, replacing the air. Exposure to these two gases happens most often in the first three weeks after the silo is filled. Tower silos and areas around stored silage should be treated as confined spaces. Due to this risk of exposure, it is suggested that you stay out of the silo for the first three weeks, unless wearing a self-contained breathing apparatus.

Besides holding deadly gases, silos can also become the sites of fires and explosions. Silo fires often result from ensiling feeds too low in moisture, usually below 45% moisture. The heating of the materials in combination with air leaks in the silo structure can allow a fire to start anywhere within the structure and to continue burning for long periods of time. Once a fire starts, it is very difficult to control or stop.

Safety Around Machinery

During silage harvest, there are risks of mechanical injuries around equipment, falls, roadway accidents, and crushing. To help prevent these injuries, be sure all shields and guards are always in place on equipment. Repairing a broken shield is as critical as replacing a broken chain. While you can have the best of intentions to not get caught in moving parts, all it takes is one slip or trip for major injuries to occur. Also be sure PTO shields are in place on silage wagons; the operations levers are only inches away from that shaft. Silage harvesters have many fast-moving unguarded parts around the head and the velocity of the silage leaving the chopper alone can cause injury. Make sure the machine is turned off when leaving the seat and that all moving parts have stopped before beginning repairs. Also, never allow anyone else near the chopper while it is running.

Be very cautious of falls. These can happen when climbing a silo, covering a bunker, or repairing a piece of equipment. Use ladders when climbing and look for ways to use a safety harness when over 6 feet in the air. In other industries, the Occupational Safety and Health Administration (OSHA) requires fall protection practices to be implemented when working over 6 feet in the air.

Often during harvest, silage is hauled down the road. Now is the time to inspect lights and turn signals on tractors, trucks, trailers, and wagons. Also be sure any slow-moving vehicle (SMV) is equipped with a highly reflective SMV sign. During harvest, be sure to wash SMV signs and lights so that they can easily be seen. Also make window and mirror washing on all equipment a daily requirement. If tractors do not have a left-hand mirror, look for a way to add one so that you can easily check for motorists that may be passing you while you are trying to turn left.

With all the additional moving equipment around the farm, be cautious of people walking around moving equipment. First be sure everyone is aware of the additional equipment moving around the farm. If backup beepers have been turned off or disabled in any way, now is the time to turn them back on or repair them. While they are loud and annoying, they do save lives. One additional safety strategy is to have everyone wear bright colors so that they can be easily seen, especially if working after dusk. The addition of reflective vests improves visibility.

Rollover Safety

Tractor rollover is a concern when packing silage piles and bunkers. According to the National Ag Safety Database, tractor overturns account for an average of 130 deaths per year in the U.S., with 80% of overturns occurring by experienced operators and one in 10 operators will overturn a tractor in their lifetime.

A properly sized tractor must be equipped with a rollover protective structure and a seat belt. Rollover protective structures became available in the mid-1960s. These structures were not available for all new tractors until the mid-1970s. They were not standard equipment on new tractors until 1985. But these structures and seat belts are 99.9% effective in preventing deaths due to tractor overturns.


Silage harvest is a busy time and brings with it potential hazards that can cause injury or death.  We encourage you to take the time now to inspect equipment, make needed repairs or adjustments, and use extreme caution. 

Additional resources are available from the Ohio State University Extension Ag Safety and Health Program at: