Public Health Statement for Ammonia
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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 ToxFAQs™, 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
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.
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 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.
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
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.
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 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
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
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.
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
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 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.
Is there a medical test to determine whether I have been exposed
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.
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% 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.
Agency for Toxic Substances and Disease Registry (ATSDR). 2004.
Toxicological profile for Ammonia.
Atlanta, GA: U.S. Department of Health and Human Services, Public Health
Where can I get more information?
If you have questions or concerns, please contact your community or state health or environmental quality department or:
For more information, contact:
Agency for Toxic Substances and Disease Registry
Division of Toxicology and Human Health Sciences
4770 Buford Highway
Chamblee, GA 30341-3717
Phone: 1-800-CDC-INFO 888-232-6348 (TTY)
Email: Contact CDC-INFO
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.