Beware of silo gas

Toxic gas associated with fermenting silage may cause severe injury or death to persons who are exposed to injurious concentrations.

Silo gas forms after chopped green forages are harvested, placed into storage and begin to ferment.

Silo gas is more commonly associated with corn silage but can also occur with hay crop silages. Nitrogen dioxide is one of the gases that are present in silo gas. 

When inhaled, nitrogen dioxide can cause burning and scarring of the lungs and respiratory system. This condition is also known as silo filler’s disease and can result in serious permanent lung injury and even death.

Symptoms of exposure to silo gas include coughing, burning, chills, fever and nausea. A farmer exposed to silo gas, may experience very mild or no symptoms and yet die while sleeping from fluid accumulation in the lungs. Farmers who suspect that they have been exposed to silo gas should seek medical assistance immediately.

Your chances of experiencing silo filler’s disease can be minimized by the following practices:

  • Do not enter the silo for two to three weeks after silo filling has been completed.
  • Run the silo blower for thirty minutes before entering the silo and leave it running while you are in the silo.
  • Level off the silo or set up the silo unloader immediately after the last load has been blown in the silo and leave the blower running while you remain inside the silo. Do not wait to do this. Any delay can allow silo gas to form and accumulate.
  • Ventilate the silo room to dissipate any silo gas that may have moved down the silo chute and collected there.
  • Use an approved self- contained air supplying breathing apparatus when entering a silo within a four to six week period after it has been filled.
  • Always have another person available to assist in an emergency.
  • Portable gas monitors are available to test for nitrogen dioxide as well as oxygen levels.

You can find more information about silo gas through the National Ag Safety Database website.

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