Silo gas is a potentially deadly hazard that poses a significant risk to farmers and agricultural workers. The term “silo gas” refers to a combination of gases including nitrogen dioxide and other nitrogen oxides.
“We are particularly concerned about the 2023 fall corn silage harvest,” said John Shutske, a professor and agricultural safety and health specialist at the University of Wisconsin-Madison. “Drought conditions and crop stress that occurred throughout much of the summer will likely result in a higher risk this year due to increased nitrate levels in plants.”
Shutske alerts the agricultural community to the dangers of silo gas by providing tips on how to recognize its presence and preventative measures to ensure safety.
What is silo gas?
According to Shutske, silo gas is a byproduct of the fermentation process that occurs when green fodder is stored in a silo. This includes corn silage as well as other plant materials. The gas is primarily composed of nitrogen dioxide (NO2), a gas that causes severe respiratory distress and even death if inhaled.
“We typically think of silo gas produced in more tightly confined tower silos which can be difficult and dangerous to access at any time if proper safety measures are not followed. However, silo gas is also produced in bunkers, piles and bags,” he said, adding that he has investigated incidents over the past 25 years where silo gas was produced. accumulated in areas adjacent to bunkers and between silo bags, causing damage to livestock. pets and birds. It can also pose a danger to people, especially on calm days or cool mornings when there is no or little air circulation.
Dangers:
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Respiratory problems: Inhalation of silo gas causes serious respiratory problems, including chemical pneumonia, pulmonary edema, and lung damage.
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Fatal Exposure: High concentrations of silo gas can be fatal within minutes.
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Delayed symptoms: The effects of exposure to silo gases are often not immediate, leading individuals to underestimate the risk. In fact, often patients who end up in the emergency room or hospital following exposure to silo gases present 8 to 12 hours after working in and around a silo, sometimes being awake late at night with serious symptoms.
Warning Features:
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Yellow-Brown Haze Vapors: A visible sign of silo gas is sometimes a yellow-brown cloud near the silo opening or next to a bag or bunker/pile.
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Pungent Odor: A pungent, bleach-like odor is often present.
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Animal Behavior: Livestock may show signs of distress or avoid the area near the silo. In some cases, dead birds may be found in areas where high gas levels are present. There is also a significant risk to pets.
Preventative measures :
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Stay away and avoid entering: Never enter a silo tower, especially within 72 hours of filling, as this is when gas concentrations are highest. With bags, bunkers and piles, it is also best to stay away from the perimeter for at least three days. Be especially careful if the weather is calm and windless. This seems to be particularly problematic here in early fall, early in the morning. With outdoor, unconfined storage, the risk generally decreases as the days get warmer and we see a nice breeze.
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Ventilation: Always provide adequate ventilation when working near silos. In the case of a tower silo, this includes the adjoining feed and silo rooms as well as neighboring areas.
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Personal Protective Equipment (PPE): It is essential to know that most types of respirators used on farms provide no protection against toxic gases like silo gases during the first few days after filling a silo . Confined silos and grain bins also generate carbon dioxide, and the only truly safe way to enter is to use a self-contained breathing apparatus or air bag. The best advice is to stay outside and wait.
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Barriers and Warning Signs: It is always best, where possible, to lock or secure areas where silo gas is likely to be present during the first two weeks after filling a silo. Where this is not practical, place visible and legible warning signs (in the appropriate language) near silos to alert others of the danger.
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Education: Ensure that all agricultural workers are informed of the risks and preventative measures associated with silo gas. This is a great topic for a tailgate training session or other weekly or bi-weekly safety meeting with hired employees.
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When entry is required: Silo gas is typically produced over a period of up to two weeks, although the greatest production occurs during the first 72 hours. During the two-week high-risk period, it is best NOT to enter the silo. If necessary, you will need to test for gas after continuously ventilating with a fan for several hours. Entry into any confined space is complex and usually requires special training, leading to the recommendation to stay outside.
In the event of an emergency evacuation, Shutske said immediate evacuation is necessary if silo gas is suspected. Seek immediate medical attention for anyone experiencing symptoms of exposure. If a person working in an area where silo gas is present collapses, call 911 and get help to the scene immediately.
“Silo gas poses a serious and often underestimated hazard in the agricultural sector,” Shutske said. “Awareness and education are the first steps to preventing tragic incidents. »
He continued: “I’m also a big believer in planning and preparing in advance. If there are ways to 100% avoid entering a silo tower or having to work around and next to bags, bunkers and piles for several days after filling, it is the “ safety practice” strongly preferred.
Training and education of hired workers and their family members on the dangers of silo gases should also include practical measures on safe working, use and limitations of protective equipment such as respirators, as well as the need for constant communication and awareness, he added.
“By understanding the risks and taking appropriate preventative measures, we can protect our farmers and farmworkers from this silent but potentially deadly danger. »