May 10, 2002

Anhydrous Ammonia Is Tough on Human Beings

Like buoys in a sea of crop land, thousands of white anhydrous ammonia tanks will be distributed across the region this spring as fieldwork gets underway. Those white tanks mark an important source of fertilizer for farmers and contain significant danger, according to a North Dakota State University agricultural safety specialist.

"Anhydrous ammonia is a highly effective form of nitrogen fertilizer," says George Maher of the NDSU Extension Service. "But it can also be a highly effective killer. According to the North Dakota Agricultural Statistics Service, North Dakota producers use about 345,000 tons of anhydrous ammonia a year.

"Because anhydrous ammonia is used so widely there are many opportunities for injury from it," says George Maher of the NDSU Extension Service. "Some exposures result in serious injury to the victim and others in short-term discomfort lasting the better part of a day or more. In general, anhydrous ammonia is not friendly to the human body."

At standard conditions, anhydrous ammonia is a clear, colorless gas with a very sharp, characteristic odor. "The odor is probably the strongest safety feature of anhydrous ammonia," Maher says. "One sniff, at only 50 parts per million concentration, clearly tells you what you are dealing with and will drive you from the area." More than a sniff can disable a person so much that escape is impossible. At 5,000 parts per million, suffocation happens quickly.

Anhydrous ammonia is a liquid when compressed or cooled. The boiling point is -28 F. "It is so cold it will freeze-burn exposed tissue," Maher says. "It can freeze skin to the point where clothing is literally frozen to the skin. The victim must have a steady flow of water over the exposed flesh to thaw the clothing from the skin. Simply pulling off the frozen clothing will result in layers of skin being pealed off too."

The injury is also a chemical burn. Anhydrous ammonia is extremely corrosive -- chemically destroying flesh, burning deep. First aid is to dilute the ammonia with a continuous flow of water. The flushing must be constant, continuing until arrival at the hospital where medical help takes over. Exposure to 2,000 parts per million will cause a burn and serious blisters. Recovery from an anhydrous exposure burn is similar to a burn from fire. Scar tissue will eventually cover the injury.

"There is a very strong attraction between anhydrous ammonia and water," Maher explains. "One gallon of water will absorb 1,300 gallons of anhydrous ammonia vapor. As a result, anhydrous will absorb moisture from any tissue: eyes, skin, mucous tissues of the nose, mouth, throat and lungs and result in a freeze-dried burn."

It will become trapped under contact lenses and seriously burn the eye, usually resulting in some blindness. Exposure to only 700 parts per million will result in permanent eye damage. Never attempt to remove contact lenses from a victim, just maintain a constant flow of clean water over the victims eyes until delivery to the hospital.

Maher says that inhaling anhydrous ammonia will result in such excruciating pain that it may prevent breathing--it could actually hurt too much to breath. Anhydrous ammonia will attack the mucous linings of the upper respiratory tract and lungs.

First aid consists of flushing the mouth and throat with as much clean water as possible. Little can be done for the lungs and upper respiratory tract except by emergency medical technicians who can administer oxygen under the direction of a physician. Recovery from such internal injury is extremely difficult at best.

Every container of anhydrous ammonia, bulk storage unit, semi-trailer tank, nurse tank, or field applicator must have the safety kit on it, Maher says. The gloves and goggles must be in excellent condition. "Gloves and goggles not used will not protect you," he notes.

"Not every exposure to anhydrous ammonia is going to result in serious, life-threatening injuries," Maher says. "But, the chance of such injury is more than enough to demand the strongest effort in preventing exposure. There is nothing wrong with being too careful and using protective equipment as much as possible. It simply reduces the risk."

For more information on safety issues relating to anhydrous ammonia applications, refer to "Anhydrous Ammonia: Managing the Risks" (AE-1149), a publication from the NDSU Extension Service available through county extension offices or on the Web at http://www.ext.nodak.edu/extpubs/ageng/safety/ae1149-1.htm . Or contact Maher at (701)231-8288.

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Source: George Maher (701) 231-8288, gmaher@ndsuext.nodak.edu
Editor: Tom Jirik (701) 231-9629, tjirik@ndsuext.nodak.ed

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