PUBLIC HEALTH STATEMENT 

 Ammonia CAS#: 7664-41-7 

Division of Toxicology September 2004 

__________________________________________________________________________________________

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 

This Public Health Statement is the summary 

chapter from the Toxicological Profile for 

Ammonia. It is one in a series of Public Health 

Statements about hazardous substances and their 

health effects. A shorter version, the ToxFAQsTM, is 

also available. This information is important 

because this substance may harm you. The effects 

of exposure to any hazardous substance depend on 

the dose, the duration, how you are exposed, 

personal traits and habits, and whether other 

chemicals are present. For more information, call 

the ATSDR Information Center at 1-888-422-8737. 

_____________________________________ 

This public health statement tells you about 

ammonia and the effects of exposure. 

The Environmental Protection Agency (EPA) 

identifies the most serious hazardous waste sites in 

the nation. These sites are then placed on the 

National Priorities List (NPL) and are targeted for 

long-term federal clean-up activities. Ammonia has 

been found in at least 137 of the 1,647 current or 

former NPL sites. Although the total number of 

NPL sites evaluated for this substance is not known, 

the possibility exists that the number of sites at 

which ammonia is found may increase in the future 

as more sites are evaluated. This information is 

important because these sites may be sources of 

exposure and exposure to this substance may harm 

you. 

When a substance is released either from a large 

area, such as an industrial plant, or from a container, 

such as a drum or bottle, it enters the environment. 

Such a release does not always lead to exposure. 

You can be exposed to a substance only when you 

come in contact with it. You may be exposed by 

breathing, eating, or drinking the substance, or by 

skin contact. 

If you are exposed to ammonia, many factors will 

determine whether you will be harmed. These 

factors include the dose (how much), the duration 

(how long), and how you come in contact with it. 

You must also consider any other chemicals you are 

exposed to and your age, sex, diet, family traits, 

lifestyle, and state of health. 

1.1 WHAT IS AMMONIA? 

Ammonia is a chemical that is made both by 

humans and by nature. It is made up of one part 

nitrogen (N) and three parts hydrogen (H3). The 

amount of ammonia manufactured every year by 

humans is almost equal to the amount produced by 

nature every year. However, when ammonia is 

found at a level that may cause concern, it was 

likely produced either directly or indirectly by 

humans. 

Ammonia is a colorless gas with a very sharp odor. 

Ammonia in this form is also known as ammonia 

gas or anhydrous (“without water”) ammonia. 

Ammonia gas can also be compressed and becomes 

a liquid under pressure. The odor of ammonia is 

familiar to most people because ammonia is used in 

smelling salts, household cleaners, and window 

cleaning products. Ammonia easily dissolves in 

water. In this form, it is also known as liquid 

ammonia, aqueous ammonia, or ammonia solution. 

In water, most of the ammonia changes to the ionic 

form of ammonia, known as ammonium ions, which 

are represented by the formula NH4

+

 (an ion is an 

atom or a group of atoms that has acquired a net 
 PUBLIC HEALTH STATEMENT 

 Ammonia CAS#: 7664-41-7 

Division of Toxicology September 2004 

__________________________________________________________________________________________

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 

electric charge by gaining or losing one or more 

electrons). Ammonium ions are not gaseous and 

have no odor. Ammonia and ammonium ions can 

change back and forth in water. In wells, rivers, 

lakes, and wet soils, the ammonium form is the 

most common. Ammonia can also be combined 

with other substances to form ammonium 

compounds, including salts such as ammonium 

chloride, ammonium sulfate, ammonium nitrate, 

and others. 

Ammonia is very important to plant, 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 manufactured ammonia is used 

as fertilizer. A third of this is applied directly to 

soil as pure ammonia. The rest is used to make 

other fertilizers that contain ammonium compounds, 

usually ammonium salts. These fertilizers are used 

to provide nitrogen to plants. Ammonia is also used 

to manufacture synthetic fibers, plastics, and 

explosives. Many cleaning products also contain 

ammonia in the form of ammonium ions. 

1.2 WHAT HAPPENS TO AMMONIA WHEN 

IT ENTERS THE ENVIRONMENT? 

Since ammonia occurs naturally in the environment, 

we are regularly exposed to low levels of ammonia 

in air, soil, and water. Ammonia exists naturally in 

the air at levels between 1 and 5 parts in a billion 

parts of air (ppb). It is commonly found in 

rainwater. The ammonia levels in rivers and bays 

are usually less than 6 parts per million (ppm; 

6 ppm=6,000 ppb). Soil typically contains about 

1–5 ppm of ammonia. The levels of ammonia vary 

throughout the day, as well as from season to 

season. Generally, ammonia levels are highest in 

the summer and spring. Ammonia is essential for 

mammals and is necessary for making DNA, RNA, 

and proteins. It also plays a part in maintaining 

acid-base balance in tissues of mammals. 

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 1 week. 

Ammonia has been found in air, soil, and water 

samples at hazardous waste sites. In the air near 

hazardous waste sites, ammonia can be found as a 

gas. Ammonia can also be found dissolved in 

ponds or other bodies of water at a waste site. 

Ammonia can be found attached to soil particles at 

hazardous waste sites. The average concentration 

of ammonia reported at hazardous waste sites 

ranges from 1 to 1,000 ppm in soil samples and up 

to 16 ppm in water samples. 

1.3 HOW MIGHT I BE EXPOSED TO 

AMMONIA? 

Ammonia is naturally produced and used by all 

mammals in their normal metabolism. Ammonia is 

produced within a person’s body each day. Most of 
PUBLIC HEALTH STATEMENT 

 Ammonia

CAS#: 7664-41-7 

Division of Toxicology September 2004

__________________________________________________________________________________________

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov

this ammonia is produced by organs and tissues, but 

some is produced by bacteria living inside our 

intestines. 

Ammonia is found naturally in the environment. 

You may be exposed to ammonia by breathing air, 

eating food, or drinking water that contains it, or 

through skin contact with ammonia or ammonium 

compounds. Exposure to ammonia in the 

environment is most likely to occur by breathing in 

ammonia that has been released into the air. 

Ammonia has a very strong odor that is irritating 

and that you can smell when it is in the air at a level 

higher than 5 ppm. Therefore, you will probably 

smell ammonia before you are exposed to a 

concentration that may harm you. Levels of 

ammonia in air that cause serious effects in people 

are much higher than levels you would normally be 

exposed to at home or work. However, low levels 

of ammonia may harm some people with asthma

and other sensitive individuals. 

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 

liquid 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 liquid 

ammonia or ammonium ion in the eyes causes 

severe eye burns and can lead to blindness. 

Outdoors, you may be exposed to high levels of 

ammonia gas in air from leaks and spills at 

production plants and storage facilities, and from 

pipelines, tank trucks, railcars, ships, and barges 

that transport ammonia. Higher levels of ammonia 

in air may occur when fertilizer with ammonia or 

ammonium compounds is applied to farm fields. 

After fertilizer is applied, the concentration of 

ammonia in soil can be more than 3,000 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. 

Household and industrial cleaning solutions may 

contain ammonia, and use of these products at home 

or work may lead to exposure to ammonia. Both 

types of ammonia cleaning solutions are made by 

adding ammonia gas to water to form liquid 

ammonia. Household ammonia cleaners typically 

contain lower levels of ammonia (between 5 and 

10%) compared to industrial cleaning solutions, 

which can contain higher levels of ammonia (up to 

25%). 

Farmers can be exposed to ammonia when they 

work with or apply fertilizers containing ammonia 

to fields. Farmers, cattle ranchers, and people who 

raise other types of livestock and/or poultry can be 

exposed to ammonia from decaying manure. Some 

manufacturing processes also use ammonia. Some 

older refrigeration units used ammonia as the 

refrigerant. 
PUBLIC HEALTH STATEMENT 

 Ammonia

CAS#: 7664-41-7 

Division of Toxicology September 2004

__________________________________________________________________________________________

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov

1.4 HOW CAN AMMONIA ENTER AND 

LEAVE MY BODY? 

Ammonia can enter your body if you breathe in 

ammonia gas or if you swallow water or food 

containing ammonium salts. If you spill a liquid 

containing ammonia on your skin, a small amount 

of ammonia might enter your body through your 

skin; however, more ammonia will probably enter 

as you breathe ammonia gas from the spilled 

ammonia. After you breathe in ammonia, you 

breathe most of it out again. The ammonia that is 

retained in the body is changed into ammonium 

compounds and carried throughout the body in 

seconds. If you swallow ammonia in food or water, 

it will get into your bloodstream and be carried 

throughout your body in seconds. Most of the 

ammonia that enters your body from food or water 

rapidly changes into other substances that will not 

harm you. The rest of this ammonia leaves your 

body in urine within a couple of days. 

1.5 HOW CAN AMMONIA AFFECT MY 

HEALTH? 

Scientists use many tests to protect the public from 

harmful effects of toxic chemicals and to find ways 

for treating persons who have been harmed. 

One way to learn whether a chemical will harm 

people is to determine how the body absorbs, uses, 

and releases the chemical. For some chemicals, 

animal testing may be necessary. Animal testing 

may also help identify health effects such as cancer 

or birth defects. Without laboratory animals, 

scientists would lose a basic method for getting 

information needed to make wise decisions that 

protect public health. Scientists have the 

responsibility to treat research animals with care 

and compassion. Scientists must comply with strict 

animal care guidelines because laws today protect 

the welfare of research animals. 

Ammonia is a corrosive substance and the main 

toxic effects are restricted to the sites of direct 

contact with ammonia (i.e., skin, eyes, respiratory 

tract, mouth, and digestive tract). For example, if 

you spilled a bottle of concentrated ammonia on the 

floor, you would smell a strong ammonia odor; you 

might cough, and your eyes might water because of 

irritation. If you were exposed to very high levels 

of ammonia, you would experience more harmful 

effects. For example, if you walked into a dense 

cloud of ammonia or if your skin comes in contact 

with concentrated ammonia, your skin, eyes, throat, 

or lungs may be severely burned. These burns 

might be serious enough to cause permanent 

blindness, lung disease, or death. Likewise, if you 

accidentally ate or drank concentrated ammonia, 

you might experience burns in your mouth, throat, 

and stomach. There is no evidence that ammonia 

causes cancer. Ammonia has not been classified for 

carcinogenic effects by EPA, the Department of 

Health and Human Services (DHHS), or the 

International Agency for Research on Cancer 

(IARC). Ammonia can also have beneficial effects, 

such as when it is used as a smelling salt. Certain 

ammonium salts have long been used in veterinary 

and human medicine. 
 PUBLIC HEALTH STATEMENT 

 Ammonia CAS#: 7664-41-7 

Division of Toxicology September 2004 

__________________________________________________________________________________________

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 

1.6 HOW CAN AMMONIA AFFECT 

CHILDREN? 

This section discusses potential health effects from 

exposures during the period from conception to 

maturity at 18 years of age in humans. 

Children are less likely than adults to be exposed to 

concentrated ammonia because most exposures to 

concentrated ammonia occur in occupational 

settings. Children can still be exposed in the same 

way as adults to ammonia gas from spills or leaks 

from ammonia tanks or pipelines, especially on 

farms where it is used as a fertilizer. Children can 

also be exposed to dilute ammonia solutions from 

household cleaners containing ammonia. 

The effects of ammonia on children are likely to be 

the same as for adults. Ammonia is an irritant and 

the solution and gas can cause burns of the skin, 

eyes, mouth, and lungs. If a spill occurs, children 

may be exposed to ammonia for a longer time than 

adults because they may not leave the area as 

quickly. 

There is no evidence that exposure to the levels of 

ammonia found in the environment causes birth 

defects or other developmental effects. It is not 

known whether ammonia can be transferred from a 

pregnant mother to a developing fetus through the 

placenta or from a nursing mother to her offspring 

through breast milk. One study in animals showed 

that exposure of mothers to very high levels of 

ammonia during pregnancy caused their newborn 

offspring to be smaller than normal, but this 

occurred at levels of ammonia that also affected the 

mothers. 

1.7 HOW CAN FAMILIES REDUCE THE 

RISK OF EXPOSURE TO AMMONIA? 

If your doctor finds that you have been exposed to 

significant amounts of ammonia, ask whether your 

children might also be exposed. Your doctor might 

need to ask your state health department to 

investigate. 

You can reduce your risk of exposure to ammonia 

by carefully using household products and by 

avoiding areas where ammonia is used or produced. 

At home, you can reduce your risk of exposure to 

ammonia by careful handling of any household 

products that contain ammonia. For example, some 

cleaning products contain ammonia; so when you 

use them, you should be sure that rooms are 

adequately ventilated during the time you are using 

them. Avoid ammonia-containing products in glass 

bottles since breakage could lead to a serious 

exposure. You should wear proper clothing and eye 

protection, because ammonia can cause skin burns 

and damage eyes if it is splashed on them. To lower 

the risk of your children being exposed to ammonia, 

you should tell them to stay out of the room when 

you are using it. While use of ammonia by a child 

is not recommended, any use by a child should be 

closely supervised by an adult. 

You can also reduce your risk of exposure to 

ammonia by avoiding areas where it is being used. 

Ammonia is used to fertilize crops, so you can 

lower your exposure to ammonia by avoiding these 

areas when it is being applied. You can also lower 

your exposure to ammonia by avoiding places 

where it is produced. Ammonia is found in many 

animal wastes, and it may be present in high 

concentrations in the air in livestock buildings. You 
 PUBLIC HEALTH STATEMENT 

 Ammonia CAS#: 7664-41-7 

Division of Toxicology September 2004 

__________________________________________________________________________________________

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 

can lower your exposure to ammonia by avoiding 

these buildings, especially if large numbers of 

animals are inside. 

If you are a worker who uses or applies ammonia 

for farming, you can reduce your exposure by using 

it according to the instructions and wearing proper 

clothing and protective gear. Be sure to follow all 

instructions and heed any warning statements. 

1.8 IS THERE A MEDICAL TEST TO 

DETERMINE WHETHER I HAVE BEEN 

EXPOSED TO AMMONIA? 

There are tests that measure ammonia/ammonium 

ion in blood and urine; however, these tests would 

probably not tell you whether you have been 

exposed because ammonia is normally found in the 

body. If you were exposed to harmful amounts of 

ammonia, you would notice it immediately because 

of the strong, unpleasant, and irritating smell, the 

strong taste, and because of skin, eye, nose, or 

throat irritation. 

1.9 WHAT RECOMMENDATIONS HAS THE 

FEDERAL GOVERNMENT MADE TO 

PROTECT HUMAN HEALTH? 

The federal government develops regulations and 

recommendations to protect public health. 

Regulations can be enforced by law. The EPA, the 

Occupational Safety and Health Administration 

(OSHA), and the Food and Drug Administration 

(FDA) are some federal agencies that develop 

regulations for toxic substances. Recommendations 

provide valuable guidelines to protect public health, 

but cannot be enforced by law. The Agency for 

Toxic Substances and Disease Registry (ATSDR) 

and the National Institute for Occupational Safety 

and Health (NIOSH) are two federal organizations 

that develop recommendations for toxic substances. 

Regulations and recommendations can be expressed 

as “not-to-exceed” levels, that is, levels of a toxic 

substance in air, water, soil, or food that do not 

exceed a critical value that is usually based on 

levels that affect animals; they are then adjusted to 

levels that will help protect humans. Sometimes 

these not-to-exceed levels differ among federal 

organizations because they used different exposure 

times (an 8-hour workday or a 24-hour day), 

different animal studies, or other factors. 

Recommendations and regulations are also updated 

periodically as more information becomes available. 

For the most current information, check with the 

federal agency or organization that provides it. 

Some regulations and recommendations for 

ammonia include the following: 

EPA regulates the ammonia content in waste water 

released by several industries. Any discharges or 

spills of ammonia of 100 pounds or more, or of 

ammonium salts of 1,000 or 5,000 pounds 

(depending upon the compound), must be reported 

to EPA. 

Some restrictions have been placed on levels of 

ammonium salts allowable in processed foods. 

FDA states that the levels of ammonia and 

ammonium compounds normally found in food do 

not pose a health risk. Maximum allowable levels 

in processed foods are as follows: 0.04–3.2% 

ammonium bicarbonate in baked goods, grain, 

snack foods, and reconstituted vegetables; 2.0% 
 PUBLIC HEALTH STATEMENT 

 Ammonia CAS#: 7664-41-7 

Division of Toxicology September 2004 

__________________________________________________________________________________________

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 

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; and 1.1% 

dibasic ammonium phosphate in baked goods, 

0.003% in nonalcoholic beverages, and 0.012% in 

condiments and relishes. 

OSHA has set an 8-hour exposure limit of 25 ppm 

and a short-term (15-minute) exposure limit of 

35 ppm for ammonia in the workplace. NIOSH 

recommends that the level in workroom air be 

limited to 50 ppm for 5 minutes of exposure. 

1.10 WHERE CAN I GET MORE 

INFORMATION? 

If you have any more questions or concerns, please 

contact your community or state health or 

environmental quality department, your regional 

Nuclear Regulatory Commission office, or contact 

ATSDR at the address and phone number below. 

ATSDR can also tell you the location of 

occupational and environmental health clinics. 

These clinics specialize in recognizing, evaluating, 

and treating illnesses resulting from exposure to 

hazardous substances. 

Toxicological profiles are also available on-line at 

www.atsdr.cdc.gov and on CD-ROM. You may 

request a copy of the ATSDR ToxProfilesTM 

CD-ROM by calling the information and technical 

assistance toll-free number at 1-888-42ATSDR 

(1-888-422-8737), by email at atsdric@cdc.gov, or 

by writing to: 

Agency for Toxic Substances and Disease Registry 

 Division of Toxicology 

 1600 Clifton Road NE 

 Mailstop F-32 

 Atlanta, GA 30333 

 Fax: 1-770-488-4178 

For-profit organizations may request a copy of final 

profiles from the following: 

National Technical Information Service (NTIS) 

 5285 Port Royal Road 

 Springfield, VA 22161 

 Phone: 1-800-553-6847 or 1-703-605-6000 

 Web site: http://www.ntis.gov/