If you are exposed to a hazardous substance such as ammonia, several factors will determine whether harmful health effects will occur and what the type and severity of those health effects will be. These factors include the dose (how much), the duration (how long), the route or pathway by which you are exposed (breathing, eating, drinking, or skin contact), the other chemicals to which you are exposed, and your individual characteristics such as age, sex, nutritional status, family traits, life style, and state of health.

Ammonia is a colorless gas with a very sharp odor. The odor is familiar to most people because ammonia is used in smelling salts, household cleaners, and window cleaning products. Ammonia easily dissolves in water. In water, most of the ammonia changes to ammonium, which is not a gas and does not smell. Ammonia and ammonium can change back and forth in water. In wells, rivers, lakes, and wet soils, the ammonium form is most common.

Ammonia is very important to animal and human life. It is found in water, soil, and air, and is a source of much-needed nitrogen for plants and animals. Most of the ammonia in the environment comes from the natural breakdown of manure and dead plants and animals.

Eighty percent of all man-made ammonia is used as fertilizer. A third of this is applied directly as pure ammonia. The rest is used to make other fertilizers that contain ammonium. Ammonia is also used to manufacture synthetic fibers, plastics, and explosives. Many cleaning products also contain ammonia.

Ammonia does not last very long in the environment. Because it is recycled naturally, nature has many ways of incorporating and transforming ammonia. In soil or water, plants and microorganisms rapidly take up ammonia. After fertilizer containing ammonia is applied to soil, the amount of ammonia in that soil decreases to low levels in a few days. In the air, ammonia will last about one week.

In the air near hazardous waste sites, ammonia can be found as a gas. Ammonia can be found dissolved in ponds or other bodies of water at a waste site. Ammonia can also be found sticking to soil at hazardous waste sites. The average concentration of ammonia reported at hazardous waste sites ranges from 1 to 1000 parts of ammonia to one million parts of soil (ppm) and up to 16 ppm in water samples.

Outdoors, you may be exposed to high levels of ammonia in air from leaks and spills at production plants and storage facilities, and from pipelines, tank trucks, rail cars, ships, and barges that transport ammonia. Higher levels of ammonia in air may occur when fertilizer is applied to farm fields. After fertilizer is applied, the concentration of ammonia in soil can be more than 3000 ppm; however, these levels decrease rapidly over a few days. Indoors, you may be exposed to ammonia while using household products that contain ammonia. Some of these products are ammonia cleaning solutions, window cleaners, floor waxes, and smelling salts. You can also be exposed to ammonia at work because many of the cleaning products there also contain ammonia. Farmers, cattle ranchers, and people who raise chickens can be exposed to ammonia from decaying manure. Some manufacturing processes also use ammonia.

You can taste ammonia in water at levels of about 35 ppm. Lower levels than this occur naturally in food and water. Swallowing even small amounts of ammonia in your household cleaner might cause burns in your mouth and throat. A few drops of liquid ammonia on the skin or in the eyes will cause burns and open sores if not washed away quickly. Exposure to larger amounts of ammonia in the eyes causes severe eye burns and can lead to blindness. Minimal Risk Levels (MRLs) are also included in Tables 1-1 and 1-3. These MRLs were derived from human and animal data for short-term and long-term exposure.

The MRLs provide a basis for comparison with levels that people might encounter either in the air or in food or drinking water. If a person is exposed to ammonia at an amount below the MRL, it is not expected that harmful (noncancer) health effects will occur. Because these levels are based only on information currently available, some uncertainty is always associated with them. Also, because the method for deriving MRLs does not use any information about cancer, an MRL does not imply anything about the presence, absence, or level of risk for cancer.

Some restrictions have been placed on levels of ammonium salts allowable in processed foods. The U.S. Food and Drug Administration (FDA) determined in 1973 that the levels of ammonia and compounds normally found in food do not pose a health risk; ammonia is necessary for normal functions. Maximum allowable levels in processed foods are as follows: 0.04 to 3.2% ammonium bicarbonate in baked goods, grain, snack foods, and reconstituted vegetables; 2.0% ammonium carbonate in baked goods, gelatins, and puddings; 0.001% ammonium chloride in baked goods and 0.8% in condiments and relishes; 0.6-0.8% ammonium hydroxide in baked goods, cheeses, gelatins, and puddings; 0.01% monobasic ammonium phosphate in baked goods; 1.1% dibasic ammonium phosphate in baked goods, 0.003% in nonalcoholic beverages, and 0.012% for condiments and relishes.

The Occupational Safety and Health Administration (OSHA) has set a short-term (15 minute) exposure limit of 35 ppm for ammonia. The National Institute for Occupational Safety and Health (NIOSH) recommends that the level in workroom air be limited to 50 ppm for 5 minutes of exposure.

The searches are carried out on a Filemaker Pro 3.0 database using Russell Owen's ROFM.acgi.

                 Agency for Toxic Substances and Disease Registry
                 Division of Toxicology
                 1600 Clifton Road, E-29
                 Atlanta, Georgia 30333

This information was provided as a public service to all who are interested in knowing as much as possible about the world around them...and NON chemists too!

Navigate Belmont WTA's Site: