Farmers in Pennsylvania are entering the early corn silage season, which brings with it a risk of silo gas exposure. Silo gas, identified as nitrogen dioxide, is produced during the fermentation process when oxygen combines with nitrates in plant materials to create nitric oxide gas. This gas then reacts with environmental oxygen to form nitrogen dioxide.
The National Farm Medicine Center describes silo gas as “an extremely toxic, yellowish-brown gas with a bleach-like odor.” Exposure can lead to severe health issues and has resulted in deaths and serious illnesses among farmers in the state each year.
RescueTechs, LLC, a group providing public safety warnings, recently reported on its Facebook page about incidents involving silo gas in Lebanon County. “We suspected we might see gas issues and the photos below are from yesterday morning in Lebanon County. Silo was filled Monday with early season corn silage,” RescueTechs said in a Sept. 3 post.
The organization emphasized that this orange smoke should not be mistaken for fire. “And I had a separate call from a farm in Berks County that they had issues as well. In so many words he said it’s the worst he has ever seen. For clarification, this silo is NOT on fire,” the post stated.
RescueTechs also highlighted the ongoing dangers during harvest time: “Every year in Pennsylvania, we learn of farmers that have either died or become seriously ill as a result of exposure to silo gas. This serves as a reminder of the dangers that farmers and potentially emergency responders can face during harvest time.”
Lebanon County is located approximately 90 miles northwest of Philadelphia.



