Warning Issued to Farmers on Danger of Silo Gas - Dry summer weather has greatly increased the chance for exposure
Albany, September 20, 1999 – This year's unusually dry summer has greatly increased the chances that farmers may be exposed to "silo gas," which can burn lungs in just a few seconds, according to the State's Departments of Health and Agriculture and Markets.
State Health Commissioner Antonia C. Novello, M.D., M.P.H., said the potential for death and injury is even greater than usual because dry weather results in a higher level of nitrates in hay and corn. Within hours after storage in a silo, fermentation begins producing nitrogen dioxide, known as silo gas and continues for about three weeks.
Dr. Novello said anyone who is near fermenting silage should be alert for bleach–like odors and yellowish–brown fumes, which indicate the presence of silo gas. Because it is heavier than air, nitrogen dioxide gas can accumulate in low areas around the silo where people and livestock may be readily exposed.
Dr. Novello also said that when silo gas is inhaled, it is known to dissolve in the moisture of the lungs and it forms nitric acid. The acid then burns the lungs, causing them to fill quickly with fluid. Smaller concentrations over short periods can cause extensive lung damage, while high concentrations can cause death in seconds. Symptoms may be immediate or may develop several hours or days after exposure.
Although silo gas can be life–threatening, when proper procedures are implemented the risk of complications can be greatly reduced. It is thus recommended that farmers stay out of upright silos for three to four weeks after filling. If it is necessary, however, to enter a silo in an emergency, it should first be ventilated for at least 30 minutes with a blower. Only a trained professional with self–contained breathing apparatus, a lifeline and an outside observer should enter the silo. A dust mask or cartridge–type respirator will not offer protection against silo gas.
Similarly, in order to ensure adequate ventilation in the feed room below the silo chute, this area must be kept sealed off from the barn for three weeks after filling the silo. Children and visitors must be kept away from the silo area during the danger period, as well.
Dr. Novello advised that anyone who experiences coughing, shortness of breath or throat irritation should get away from silage immediately. Anyone who suspects even a brief exposure to silo gas should seek immediate medical attention.
For more information about nitrogen dioxide or the hazards of stored silage, contact your local Cooperative Extension office; the New York Center for Agricultural Medicine and Health at 1–800–343–7527; or the New York State Department of Health at 1–800–458–1158, ext. 27900.