Anhydrous ammonia: Handle with care

Anhydrous ammonia, ammonia that is nearly 100 percent pure, is commonplace in farmers’ chemical toolkits because it can be a cost-effective and efficient way to get much-needed nitrogen to crops early in their growth cycle, producing stronger plants and boosting yields.

In its pure form, though, ammonia is very caustic, and that makes handling it a challenge. According to the Agency for Toxic Substances and Disease Registry, exposure to the chemical can cause irritation and serious burns on the skin and in the mouth, throat, and eyes, and can even result in blindness, lung damage, and fatal injury. If you’re going to be using anhydrous ammonia as part of your farming operation, you need to know the basics.

Storing it

Because pure ammonia turns into vapor at −28 °F at normal atmospheric pressure, storing it in its liquid state requires extreme pressure or extremely low temperature. The Occupational Safety and Health Administration (OSHA) has strict guidelines governing these procedures. If you come into contact with anhydrous ammonia, you should be intimately familiar with them.

Pressurized anhydrous ammonia must be stored in a container that maintains the required pressure of 250 psi. The tanks used for storage or transport should be carbon steel that can handle that kind of pressure.
Hoses attached to tanks must be rated at 350 psi.

Safety

Proper gear and clothing

NH3-rated goggles, preferably ventless; or full-face shield
Rubber gloves with long cuffs
Long sleeves and pants
No contact lenses, which can trap the gas and fuse to the eye

In case of exposure

Anhydrous ammonia’s effects on the human body depend on the amount of exposure and range from mild irritation to severe and permanent injury or death. While there is no antidote to ammonia poisoning, supportive treatment measures for exposure include airway management and lots of water. Each person working with the chemical should have a personal eyewash bottle, and every transport vehicle should carry a 5-gallon container of clean water.

According to Ag Safety and Health, here are some key things to know:

If someone gets ammonia in their mouth or nostrils, the areas should be copiously irrigated with clean water for at least 15 minutes.
If ammonia is ingested, the victim should drink milk or water to dilute it.
Remove any contaminated clothing unless it is frozen to skin
Seek professional medical attention immediately, making sure medical staff are aware that the victim was exposed to anhydrous ammonia.
Ointments can intensify the damage
If water is not available, another non-toxic liquid, like juice, milk, or cold coffee can be used.

It’s also important to have water on hand to mitigate fire risk. Ammonia is not easily flammable, but as it is stored under such enormous pressure, if a fire should occur where it’s stored, the results can be catastrophic. Water can cool ammonia containers that have caught fire or reduce the concentration of ammonia vapor in case of accidental release.

The information included here was obtained from sources believed to be reliable, however Grinnell Mutual Reinsurance Company and its employees make no guarantee of results and assume no liability in connection with any training, materials, suggestions, or information provided. It is the user’s responsibility to confirm compliance with any applicable local, state, or federal regulations. Information obtained from or via Grinnell Mutual Reinsurance Company should not be used as the basis for legal advice and should be confirmed with alternative sources.

Sources: The American National Standards Institute (ANSI); Bayer; Compressed Gas Association (CGA); The Fertilizer Institute; Minnesota Department of Agriculture; OSHA; Centers for Disease Control and Prevention

3/2024