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Anhydrous Ammonia Safety Information

Everything You Ever Wanted to Know But Didn’t Want to Ask

Anhydrous Ammonia is a compound formed by the chemical combination of the two gaseous elements nitrogen and hydrogen. Anhydrous means "without water" and when used with the word ammonia indicates that the water content is less than 0.2 percent. This distinguishes it from aqueous solutions of ammonia.

Ammonia is one of the top twenty highest volume chemicals produced in the United States. Approximately, 80 percent of all ammonia produced in this country is used in agriculture as a source of nitrogen. Nitrogen and other elements essential to plant growth must be restored to maintain soil fertility following the harvesting of fruit, vegetable or grain crops. Ammonia is also used as a refrigerant, in pH control efforts, explosives manufacturing, metal-treating operations and chemical manufacturing.

The properties of Ammonia make it one of the most potentially dangerous chemicals used in agriculture. At room temperature and normal atmospheric pressure, ammonia is a pungent, colorless, lighter than air gas. Because of it’s relatively low boiling point (-28° F) ammonia is easily liquifiable. Ammonia is usually shipped as a liquid since more material can occupy the same space in a liquid form rather than as a gas. If Ammonia is to be stored above this boiling point it must be kept under pressure or maintained at the boiling point temperature of minus 28 degrees. Ammonia in unrefrigerated storage tanks expands and increases the vapor pressure in the tank as the outside temperate fluctuates.

For example, at 60° F the pressure in the tank is 93 psig and when the outside temperature is at 100° F the pressure in the tank is 200 psig. If a hose ruptures or a valve is unintentionally opened, the high pressure from a tank can cause ammonia to spray out possibility into your eyes, face, and other parts of your body before you can react.

When pressure is released on liquid ammonia it quickly converts to a gas. One gallon of liquid ammonia will turn to a vapor cloud that is just under 5 feet by 5 feet by 5 feet or 113 cubic feet in size. This conversion will freeze atmospheric moisture forming a white colored cloud. The temperature of the vapor cloud can range from -45° F to -100° F in the first 10 to 12 feet of the vapor cloud which may rapidly freeze everything it touches. As a liquid pool of ammonia warms from it’s boiling point of -28° F and turns to a gas it will rise. Ammonia vapor has a vapor density of approximately 0.597 compared to air at 1. Ammonia vapors will rise and easily travel with any wind present. Personnel downwind of any spill must be notified and warned of the potential hazard heading in their direction.

The acute effects of ammonia are listed below:

Earlier it was explained that the word anhydrous means "without water." This factor contributes to the hazardous nature of ammonia. When it comes in contact with any moisture, the water and ammonia quickly combine. If ammonia contacts your eyes, skin or mucous membranes it will quickly cause rapid dehydration and severe burns as it combines with the moisture of your body. The speed with which you wash the ammonia from your eyes or skin will determine the degree of injury. The eyes are especially vulnerable to severe injury due to the amount of water or fluid contained there. Similarly, the respiratory tract and skin are easily burned due to the percentage of moisture found there.

Anhydrous ammonia is caustic and causes severe chemical burns. Body tissues that contain a high percentage of water, such as the eyes, skin, and respiratory tract are very easily burned. Victims exposed to even small amounts of ammonia require immediate treatment with large quantities of water to minimize the damage.

Warning Properties/ Personal Protective Equipment/Respirators

Ammonia's odor threshold is sufficiently low to acutely provide adequate warning of its presence. However, ammonia causes olfactory fatigue(loss of sense of smell) or adaptation, making its presence difficult to detect when exposure is prolonged.

Eye Protection Requirements: Full eye and face protection.

Hand Protection Requirements: Butyl rubber.

Protective Clothing Requirements: Impervious clothing where contact with liquid is possible.

Half face cartridge respirator with appropriate NH₃ cartridge(s):Upper Limit: 100 ppm

Full face chemical cartridge respirator with appropriate NH3 cartridge(s):Upper Limit: 300 ppm

Full face respirator (gas mask type) with appropriate NH₃ canister:Upper Limit: 500 ppm

Supplied air respirator, or self-contained breathing apparatus:Unlimited

Remove the victim from the contaminated area while protecting yourself. Initiate artificial respiration and supply oxygen if needed. Keep victim warm and at rest. Seek medical attention, pulmonary injury may continue to evolve over 18 to 24 hours. If patient is conscious, the irritation of the throat may be relieved by water in the mouth. Seek medical attention immediately.

First Aid for Eye Contact:

Remove victim from the source of contamination and take to nearest eye wash or shower. Immediately wipe away any excess chemical very gently and quickly. Wash the affected eye or eyes under slowly running water for 15 minutes or longer, making sure the eyelids are held wide apart and moved slowly in all directions.

Remove victim from source of contamination and take immediately to nearest shower or source of clean water. Wash victim down taking care to protect eyes. Wash until the feeling of stickiness or soapiness disappears. This may take an hour or more.

Loosen tight clothing around the neck and waist. Flush mouth several times with cold water and spit out. Give victim 1 to 2 cups of milk. Do not induce vomiting. Do not give oils or attempt to neutralize with an acid. Do not give sodium bicarbonate or carbonated drinks. If vomiting occurs, keep the head lower than the hips to prevent vomitus from entering the lungs.

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Other Ammonia Safety Resources

MSDS (MATERIAL SAFETY DATA SHEET)

To receive a free copy of Dakota Gasification Company’s "Ammonia Safety Training Manual", email Steve Liebelt or contact him at (701)221-4418.

To obtain the publication, "Storage and Handling of Anhydrous Ammonia", contact the American Standards Institute in New York at (212)642-4900.

To obtain the publication, "C-2, Anhydrous Ammonia", contact the Compressed Gas Association in Arlington, VA at (703)412-0900.

To obtain the publication, "Ammonia Data Book", contact the International Institute of Ammonia Refrigeration" in Wash., DC at (202)857-1110.

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