The death of a Wisconsin dairy farmer this past week is a grim reminder that farms provide for a dangerous work environment. Sometimes one with unsuspecting hazards.
The young dairy farmer was overcome with manure gases from an open manure lagoon. He died instantly, as did some nearby livestock. This occurred while being outside in an unconfined area. His sister relays the account of his death as follows:
“Mike woke up early in the morning Monday to turn the agitator on for the open manure pit because they were going to haul manure that day. There was a dense fog (1,000-foot cap, according to the National Weather Service) and he turned the agitator on, which caused the release of manure gas and strong fumes. Normally the fumes (gas) would spread throughout the air, but with the dense fog (lack of air movement), this did not occur; it stayed condensed and took Mike’s life very quickly.”
The potential for injury or death looms across most farmsteads. No enterprise, livestock species, or crop type gets a pass. It comes with the territory. One specific potential hazard within the forage enterprise is silo gas and silages in 2016 may be at higher risk than some other years.
Recently, there has been a lot of information coming from university specialists discussing the risk of high-nitrate forages induced by dry soil conditions. Feeding those forages directly to livestock becomes a concern, whether grazed, greenchopped, or dried and baled.
It’s also known that if high-nitrate forages are harvested for silage and allowed to ferment, nitrate concentrations are reduced 30 to 50 percent. That nitrogen is lost in the form of what most of us call silo gas. Hence, higher nitrate forages have the potential to create greater amounts of gas.
Though any forage has the potential to generate silo gas, grass crops generally pose the greatest risk. Corn silage is often associated with high levels of silo gas, especially if harvested soon after a rain event that was preceded by dry soil conditions.
Silo gas begins to form immediately after forage is put into a silo. It includes nitrogen oxide, which converts to nitrogen dioxide in the presence of oxygen. Nitrogen dioxide is a highly corrosive, toxic gas, which forms nitric acid when mixed with water.
Silo gas also contains carbon dioxide, which is not toxic but is heavier than air and displaces oxygen. In a sealed, oxygen-limiting silo, carbon dioxide is produced in higher amounts than nitrogen dioxide. It’s the carbon dioxide that displaces the oxygen within the sealed structure.
Being heavier than air, silo gas will settle on the surface of the silage; if a chute door is open close to the silage surface, gas will flow down a silo chute and into feeding areas. In extreme situations, silo gas appears as a yellowish-brown “smoke” that can move downward or out of the top of silo if it is nearly full.
When inhaled, the nitrogen dioxide in silo gas mixes with the moisture in the body, forming nitric acid. This causes severe burning and scarring of the lungs and other parts of the respiratory system.
The effects of silo gas on the human body can be immediate if concentrations are high. People exposed to silo gas may collapse and die from the gas or lack of oxygen. Victims of silo gas have also been known to die many hours later, sometimes in their sleep, from the buildup of fluid in the lungs.
Get fresh air and see a doctor immediately if you’ve been exposed to silo gas, even if you feel better after getting fresh air.
To prevent silo gas exposure, the following steps are recommended:
· Stay out of a tower silo for two to three weeks after filling. This is the peak period of silo gas formation. Keep the silo room closed off from the rest of the barn, and ventilate to remove any gas that flows down the chute.
· Before you enter a tower silo for the first time, run the forage blower for 30 minutes, and leave it running while inside. Ventilate the chute and silo room as well. Have someone with you outside of the silo to go for help if needed.
· If you must enter the silo to level off or set up an unloader after filling, do so immediately after the last load is blown into the silo. Do not wait until after supper or the next day. The blower should be running while you are inside.
· Since silo gas settles down on the silage surface, be aware that a forage blower may not adequately ventilate a partly filled silo. Leave silo doors open to allow gas to escape, but be sure to close off and ventilate the silo room.