Farm Horizons, February 2017
Brownton area incident highlights anhydrous ammonia safety
By Gabe Licht
Anhydrous ammonia was last applied a couple months ago, and it will be a couple more months before the next application, but it’s never a bad time to talk about anhydrous ammonia safety.
That fact was highlighted by a Nov. 14 anhydrous ammonia spill north of Brownton.
According to McLeod County Emergency Management Director Kevin Mathews, the incident was reported at 10:48 p.m. near the intersection of Plum Avenue and 90th Street about a mile north of Brownton.
It appears a mechanical failure caused a hose or valve to leak.
Members of the Brownton Fire Department were able to shut off the valves on the tanks in the field.
The anhydrous ammonia that had escaped formed a cloud that crept along the ground.
“Especially that night we had a foggy night,” Mathews said. “The deputies and firefighters going out into the area were driving around and not seeing they were in the anhydrous cloud. If it’s clear, night or day, you can see the white cloud. With the fog, it was hard to tell.”
Some area residents also drove into the cloud before retreating.
According to Mathews, none of those individuals nor the farmer or emergency personnel sought medical treatment for anhydrous ammonia exposure, which can hamper breathing.
To prevent others from driving into the cloud, Mathews and emergency personnel established a perimeter around the site, shutting down roads in a section measuring 6 square miles, including Highway 15.
“The cloud dissipated and we had responders who could smell it on Highway 15 a couple miles away,” Mathews said.
His department utilized CodeRed and IPAWS (Integrated Public Alert and Warning System) to notify people in that area of the situation. One family voluntarily evacuated, while the majority sheltered in place until the cloud dissipated.
By 2:30 a.m., the situation was resolved and roads were reopened.
Mathews said he was pleased with how the situation was handled.
“I think, overall, it did go very well,” Mathews said, noting that fire department training for such situations paid off.
Such situations are fairly uncommon. Mathews recalls two or three incidents over the past 10 years.
University of Minnesota Extension offers a number of safety tips regarding anhydrous ammonia.
First, it must be stored and handled under high pressure, requiring specially designed and well-maintained equipment.
Because anhydrous ammonia is caustic and causes severe chemical burns, chemical-proof goggles or full-face respirator, rubber gloves, and a heavy-duty long-sleeved shirt are required for anyone handling anhydrous ammonia.
Regulations require all anhydrous ammonia nurse tanks and applicator tanks carry at least one five-gallon container of clean water for flushing eyes and skin in case of exposure. A second 5-gallon container of water should be kept on the tractor, and water in both containers should be changed daily. Handlers should also carry an 8-ounce eye-wash plastic water bottle at all times, in case of an accidental exposure.
For those storing bulk quantities of anhydrous ammonia, a rainsuit and two gas masks with currently dated ammonia canisters must be available for emergency work.
Regularly-scheduled maintenance is needed to ensure the tank and components are ready for service.
Before using ammonia equipment, perform a walk-around inspection using a safety checklist from an anhydrous ammonia supplier to locate any defects.
Hoses, especially, must be checked carefully before each use, and should be replaced if there are bulges, cracks, cuts, soft spots, or blisters.
Tanks should not be filled to more than 85 percent of capacity, as increasing outside temperatures cause the liquid to expand and the vapor pressure in the tank could rise to a potentially dangerous level, leading to a possible rupture or explosion.
A break-away coupler in the ammonia line that runs to a tool bar is a recommended safety precaution to provide protection if the equipment separates accidentally.
When towing a nurse tank, drive at speeds of 25 mph or slower. In Minnesota, anhydrous ammonia tanks must be equipped with two red reflectors at the extreme left and right rear sides of the end of the wagon. The widest portion of the towing vehicle and wagon combination must also display a red or amber light at the extreme left end of the combination visible from the rear and an amber or white light visible from the front.
If skin is exposed to anhydrous ammonia, flush the exposed area with clean water for at least 15 minutes. Remove contaminated clothing. Do not apply salves, creams, or ointments, which may seal residual ammonia in the skin and cause further damage.
Eyes should also be flushed for 15 minutes or more if ammonia enters them.
Doctors should be contacted immediately after administering emergency first aid.
If ammonia is inhaled in high concentrations, cardiopulmonary resuscitation may be required.
If ammonia is swallowed, contact a doctor immediately. If possible, drink large amount of water to dilute the chemical. Vomiting should not be induced if a victim is in shock or unconscious. If vomiting occurs, keep the head lower than the hips to prevent vomit from entering the lungs.
For more information, contact the Fertilizer Institute, American National Standards Institute, Minnesota Crop Production Retailers, National Safety Council, or Minnesota Department of Agriculture.