Dr. Ken Griswold has made a career out of forages as a part of the Penn State Cooperative Extension dairy team. While that does mean he’s an expert in the field, it doesn’t mean he’s immune to the dangers that come with putting up high-quality forages.
This past September, Griswold was working in an upright silo and was exposed to silo gas. He already felt sick by the time he got home. That night, after falling asleep in a chair, he started coughing up a pink, foamy liquid.
He couldn’t breathe deep enough to yell for his wife and it took him an hour and a half to climb the stairs to get her to call 911.
Griswold was rushed to the emergency room. Although the hospital was in the heart of Pennsylvania’s dairy country, the doctors were inexperienced with silo gas (NO2) exposure.
After he was finally diagnosed with silo filler’s disease, he was put on a high dose of steroids to reduce the swelling in his lungs. When he started weaning off the prescription a couple weeks later, he relapsed and again started coughing blood.
This time, after being readmitted to the hospital, he worked with one of the few doctors in the U.S. who specialize in silo gas. Today, he is still taking the prescription and is back to 98 percent lung function. His doctor said he is fortunate in that he will likely regain 100 percent function.
Silo filler’s disease is most often associated with upright silos, but Griswold said exposure can happen with bunkers too. That’s why he said it’s so important for custom harvesters and producers to take this hazard seriously and approach it with an attitude of safety first.
The Occupational Safety and Health Administration (OSHA) lists the permissible exposure limit for NO2 gas at 5 ppm, but does not recommend exposure at greater than 1 ppm.
According to Griswold, the maximum NO2 production is in the first three to five days after the forage is put up. Thus, if at all possible, producers should stay out of the silo for 21 days to limit exposure potential.
However, if you must absolutely enter the silo, follow these safety tips:
- Use a blower to ventilate the silo for a minimum of 30 minutes before entering and keep the doors closed while you’re ventilating. NO2 is a heavy gas and sinks. If the doors are open, it will push the gas toward you in high enough amounts that it can make you collapse. Many falls actually occur due to silo gas.
- Keep the fans running the entire time you’re in the silo.
- Do not enter the silo from the top. If you are exposed to silo gas, you will likely be too weak to climb out of the silo.
- If you see or smell gas at any time, get out immediately.
- Perhaps most importantly, tell someone if you will be working in or around a silo. This person can watch out for you and call for help in the event that you collapse and are unable to do so yourself.
The dangers of harvesting and feeding forages don’t end with silo gas. "Avalanches" in bunker silos are equally dangerous.
According to Griswold, avalanches – or collapses – occur because of overfilling, inappropriate face management (digging instead of shaving) and undersized equipment.
He said the middle of the bunker is most susceptible to collapses when the progressive wedge packing technique is used. That’s because the thicker layer at the top and in the middle of the bunker has no static pressure from the sides to hold it in place.
When working at the face, Griswold recommends the "3x rule." Be three times as far from the face as the height of the pile.
If you absolutely must be close to the face (to take core samples, for example), Griswold said you should harness yourself to a loader. That way, if a collapse should happen, the loader driver can pull you out of the pile. Griswold said you’ll most likely still get injured, but hopefully not as severely.
You should also be aware of your surroundings at all times. For example, if you’re near the face of a bunker, know how close to the edge the tires are. Otherwise, equipment could snag the plastic and pull a tire on top of you.
Size your equipment appropriately. Your payloader should be able to reach the top of the face and shave it. If you just let the forage fall instead of shaving it, you open yourself up for some dangerous consequences.
Lastly, Griswold said you can’t get complacent.
"No matter how many times you do something dangerous and walk away, it only takes one time for your family to pay the price for your arrogance," he said.
Griswold said safety isn’t something that applies to the producer only. Custom harvesters need to be equally attentive. They should work to put up forages as safely as possible and point out any potential hazards to the producer.
"You have an influence on the safety that happens on that farm," Griswold said. "You have an obligation to your customer to help keep them safe." FG
