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Anhydrous ammonia tanks DarcyMaulsby/Getty Images
BE CAREFUL: Anhydrous ammonia seeks out moisture and will cause severe burns to the eyes, skin and respiratory tract. Substantial exposure can result in death.

Anhydrous ammonia is effective but can be deadly

Be aware of risks when handling NH3.

It’s a deadly, colorless gas. Most farmers look at anhydrous ammonia as a source of the cheapest nitrogen fertilizer, but it’s critically important to remember that first sentence.

The chemical is both caustic and hazardous, and when concentrated, can burn human skin upon contact.

It seeks out moisture and will cause severe burns to the eyes, skin and respiratory tract. Its rapid evaporation creates an almost instant freeze-drying effect — and exposure to ammonia in sufficient quantities can be fatal. Its toxicity was recently underscored by the roadside accident and release of anhydrous ammonia that resulted in an evacuation outside of Chicago.

It’s expected that more anhydrous ammonia will be applied this spring than in past years because it was so wet in the fall. Harvest was delayed, and winter set in before ammonia could be applied.

Stored as a liquid under pressure, NH3 vaporizes to a colorless gas at atmospheric pressure and a temperature of −28 degrees F. The incidental release of anhydrous ammonia can create a dangerous situation for both the handler and bystanders. It’s important to know wind direction and stay upwind when operating valves.

At Ohio State University, S. Dee Jepsen, associate professor; and Kent McGuire, College of Food, Agricultural and Environmental Sciences safety and health coordinator, have identified the following situations that can lead to an incidental release or personal injury:

• overfilling the tank

• handling the hose by the valve handle or hand wheel

• weakened undercarriage structure

• moving the tank before disconnecting the hose

• faulty valves and deteriorated or out-of-date hoses

• failure to bleed pressurized NH3 from the hose before connecting or disconnecting

• overturning an applicator tank

• external overheating of the storage container

• faulty hitch pin or weakened tongue

• not using personal protective equipment

• failure to have sufficient amounts of water available

An estimated 80% of reported incidents result from improper procedure, lack of knowledge or training, and failure to follow proper safety precautions, according to Jepsen and McGuire.

So, as you head to the fields this spring, make sure that equipment is properly maintained, and only allow trained and educated individuals — following prescribed safety rules — handle and apply anhydrous ammonia.

However, if you should have an incident, Jepsen and McGuire say to wash with water when skin or eyes are exposed to anhydrous ammonia. Time is important! Get water onto the exposed area of the skin or eyes immediately, and flush for at least 15 minutes.

Contaminated clothing should be removed quickly but carefully. Thaw clothing frozen to the skin with water before attempting removal. Wash the affected skin area with abundant amounts of water, and do not apply anything except water for the first 24 hours. Stay warm and get to a physician immediately.

Water must be available for flushing the eyes and skin in case of exposure. Each vehicle used for anhydrous ammonia must carry a 5-gallon container of clean water. Individuals handling NH3 should carry a 6- to 8-ounce squeeze bottle of water in their shirt pocket for rapid emergency access.

Be careful out there. Remember, it’s a deadly, colorless gas.

Read OSU’s entire report, Safe Handling of Anydrous Ammonia, online.



TAGS: Safety
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