Anhydrous Ammonia Application Safety Tips
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The physical properties of anhydrous ammonia (NH3) make it one of the most potentially dangerous materials to handle on the farm. Exposure to this colorless, high-pressure liquid, which converts to a liquid gas can cause serious injuries. For example, anhydrous can freeze and/or burn skin, lead to blindness if it gets in the eyes and even cause death when inhaled.
“I can’t overemphasize the importance of safety with anhydrous,” says Ryan Bergman, Technical Project Specialist in Agricultural and Biosystems Engineering at Iowa State University. “It’s critical to always keep tabs on wind direction and stay up wind whenever possible when hooking up, filling tanks, and applying the product, along with keeping a respirator handy at all times.”
“I can’t overemphasize the importance of safety with anhydrous.”
According to the National Ag Safety Database, common examples of misusing anhydrous ammonia and its equipment that can result in dangerous accidents include:
- Filling tanks too full.
- Accidentally knocking open the hose-end valve.
- Moving the applicator tank before disconnecting filling hoses from the nurse tank.
- Venting pressure release valve while a person is in line of discharge.
- Breaking the transfer hose, especially an old or misused one.
- Failing to bleed hose coupling before disconnecting.
- Rupturing of low-pressure hose due to pressure buildup when knives plug.
- Releasing ammonia when knives are unplugged.
- Overturning an applicator or nurse tank while in transit or in the field.
Safety First
NH3-approved goggles and a face shield or a full-face respirator should be used to protect the eyes, face and lungs. In addition, loose-fitting, chemical-resistant rubber gloves and long-sleeve work shirts or overalls help reduce direct exposure.
Every second is critical should you be sprayed with sub-zero-temperature liquid ammonia or engulfed in concentrated vapors. Skin or eye tissue damage is immediate and must be flushed with clean water immediately for a minimum of 15 minutes. Thaw frozen clothing with water, then remove quickly and carefully. Carry an eyewash bottle of water in your pocket and have five-gallon containers of fresh water on the nurse tank, in the tractor and in the truck.
Every second is critical should you be sprayed with sub-zero-temperature liquid ammonia or engulfed in concentrated vapors.
Inhaling pungent ammonia vapors, even in low concentrations, can irritate the respiratory tract and lungs. High vapor concentrations can result in damaged lung linings and even death. Move the exposed person to a safe area, call 911 and administer CPR if needed.
Bergman cites a few examples of memorable anhydrous application calls he received last fall. In one incident, a hose/valve failed, and pressurized anhydrous was leaking, aimed directly at the tractor. The quick-thinking operator put the tractor in high gear and drove around the field in circles until the tank was empty. “If he hadn’t done this, the entire tractor would have been engulfed in the gas cloud, creating a bad situation,” Bergman says.
The other incident involved a tank valve that started leaking during highway transport. “Both of these examples drive home the point of proper maintenance and hookup to equipment,” Bergman adds.
Along with staying upwind when operating valves, other safety reminders include:
- Minimize handling hoses filled with ammonia.
- When connecting hoses, follow this order: 1) connect all hoses; 2) tighten bleeder valves; 3) open valves beginning with the furthest downstream and work upstream. The last valve opened should be the one releasing ammonia into the hose.
- When disconnecting a hose, first close the valve supplying ammonia to the line and then successive valves downstream to the disconnect. This approach should help avoid trapping a large amount of ammonia in the line. Next open bleeder valves in the identical order valves were closed before finally disconnecting the line. Small amounts of chilled, liquid ammonia frequently remain in ammonia plumbing even after bleeding the system until all ammonia is warmed enough to volatilize.
- Respect ammonia plumbing and use appropriate personal protective equipment.
Additional Safety Resources
For excellent anhydrous ammonia safety advice, view this 60-minute North Dakota State University webinar designed for anyone who works with the fertilizer. Another recommend resource is the NDSU Extension bulletin: “Anhydrous Ammonia: Managing the Risks.”
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