Warning Issued to Farmers on Danger of Silo Gas

Dry Summer Weather Increases Exposure Concerns

Albany, October 10, 2002 – This year's unusually dry summer has greatly increased the chances that farmers may be exposed to "silo gas," which can cause significant lung injury when just a few breaths are inhaled, according to the New York State Department of Health, the New York Center for Agricultural Medicine and Health (NYCAMH), and the New York State Department of Agriculture and Markets.

State Health Commissioner Antonia C. Novello, M.D., M.P.H., Dr.P.H. said that when silo gas is inhaled, it is known to dissolve in the moisture of the lungs, forming 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.

State Agriculture Commissioner Nathan L. Rudgers said, "Filling and unloading silos always requires care, but this year, due to the dry weather we have experienced, the threat of silo gas is even greater than normal. The safety recommendations are critically important. In the rush to get corn chopped and the silage in this fall, please be cautious when working around and entering recently-filled silos."

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. Family members or co-workers should NOT enter a silo where someone has been overcome. The silo blower should be turned on immediately and trained rescue personnel who can enter with self-contained breathing apparatus should be summoned.

The potential this year for death and injury is increased because dry weather results in a higher level of nitrates in hay and corn. Within hours after storage in upright silos and "ag bags" , fermentation begins producing nitrogen dioxide, known as silo gas, and continues for about three weeks after silo filling is complete.

Dr. Novello said anyone who is near recently filled silos or "ag bags" should be alert for bleach-like odors and yellowish-brown or orange colored fumes, which may indicate the presence of silo gas. However, concentrations too low to be smelled or seen may be harmful as well. Because it is heavier than air, silo gas can accumulate in low areas around the silo and near the open ends of "ag bags" where people and livestock may be readily exposed. Precautions should be taken to avoid these areas for at least three weeks after filling is complete. Children and visitors must be kept away from these areas during the danger period, as well.

Dr. John May, the medical director of NYCAMH, said that although silo gas can be life threatening, when proper procedures are implemented the risk of complications can be greatly reduced. When filling a silo, use of a mechanical silage distributor for leveling is recommended. If manual leveling is necessary, do so immediately after filling and only while the blower is still running. A silo should never be entered unless the blower has been running for at least 30 minutes. However, farmers must recognize that silos with excessive headspace above the silage will not be effectively ventilated by the blower. Silage should be capped and the silo closed up immediately after filling is completed.

Dr. May recommended that farmers stay out of silos and the area around the base of the silos for at least three weeks after filling. If it is necessary to enter a silo in an emergency, only a trained professional with self-contained breathing apparatus should do so. In such a situation, trained rescuers should only enter a silo while attached to a lifeline attended by an outside observer. A dust mask or cartridge-type respirator will not offer protection against silo gas.

For more information about silo gas or the hazards of stored silage, contact 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.

10/10/02—113 OPA