- What are fluoride, hydrogen fluoride, and fluorine?
- What happens to fluoride, hydrogen fluoride, and fluorine when they enter the environment?
- How might I be exposed to fluoride, hydrogen fluoride, and fluorine?
- How can fluoride, hydrogen fluoride, and fluorine affect my health?
- How likely are fluoride, hydrogen fluoride, and fluorine to cause cancer?
- How does fluoride, hydrogen fluoride, and fluorine affect children?
- How can families reduce their risk for exposure to fluoride, hydrogen fluoride, and fluorine?
- Is there a medical test to show whether I've been exposed to fluoride, hydrogen fluoride, and fluorine?
- Has the federal government made recommendations to protect human health?
- Where can I get more information?
ToxFAQs™ for Fluorides, Hydrogen Fluoride, and Fluorine
Spanish: Flúor, el Fluoruro de Hidrógeno y Fluoruros
CAS#: Hydrogen Fluoride 7664-39-3; Fluorine 7782-41-4; Sodium Fluoride 7681-49-4
PDF Versionpdf icon[545 KB]
This fact sheet answers the most frequently
asked health questions about fluoride, hydrogen fluoride,
and fluorine. For more information, you may call the ATSDR
Information Center at 1-888-422-8737. This fact sheet is one
in a series of summaries about hazardous substances and their
health effects. 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
Fluorides are naturally
occurring compounds. Low levels of fluorides can help
prevent dental cavities. At high levels, fluorides can
result in tooth and bone damage. Hydrogen fluoride and
fluorine are naturally-occurring gases that are very irritating
to the skin, eyes, and respiratory tract. These substances
have been found in at least 188 of the 1,636 National
Priorities List sites identified by the Environmental
Protection Agency (EPA).
What are fluoride, hydrogen fluoride, and fluorine?
Fluorides, hydrogen fluoride, and fluorine
are chemically related. Fluorine is a naturally-occurring,
pale yellow-green gas with a sharp odor. It combines with
metals to make fluorides such as sodium fluoride and calcium
fluoride, both white solids. Sodium fluoride dissolves easily
in water, but calcium fluoride does not. Fluorine also combines
with hydrogen to make hydrogen fluoride, a colorless gas. Hydrogen
fluoride dissolves in water to form hydrofluoric acid.
Fluorine and hydrogen fluoride are used
to make certain chemical compounds. Hydrofluoric acid is used
for etching glass. Other fluoride compounds are used in making
steel, chemicals, ceramics, lubricants, dyes, plastics, and
pesticides. Fluorides are often added to drinking water supplies
and to a variety of dental products, including toothpaste
and mouth rinses, to prevent dental cavities.
What happens to fluoride, hydrogen fluoride, and
fluorine when they enter the environment?
- Fluorine cannot be destroyed in the environment; it can
only change its form. Fluorine forms salts with minerals
- Hydrogen fluoride gas will be absorbed by rain and into
clouds and fog to form hydrofluoric acid, which will fall
to the ground.
- Fluorides released to the air from volcanoes and industry
are carried by wind and rain to nearby water, soil, and
- Fluorides in water and soil will form strong associations
with sediment or soil particles.
- Fluorides will accumulate in plants and animals. In animals,
the fluoride accumulates primarily in the bones or shell
rather than in soft tissues.
How might I be exposed to fluoride, hydrogen
fluoride, and fluorine?
- The general population can be exposed to fluorides in contaminated air, food, drinking water and soil.
- People living in communities with fluoridated water or high levels of naturally-occurring fluoride may be exposed to higher levels.
- People who work or live near industries where fluoride containing substances are used may be exposed to higher levels.
How can fluoride, hydrogen fluoride, and fluorine
affect my health?
Small amounts of fluoride help prevent
tooth cavities, but high levels can harm your health. In adults,
exposure to high levels of fluoride can result in denser bones.
However, if exposure is high enough, these bones may be more
fragile and brittle and there may be a greater risk of breaking
the bone. In animals, exposure to extremely high doses of
fluoride can result in decreased fertility and sperm and testes
Fluorine and hydrogen fluoride are very
irritating to the skin, eyes, and respiratory tract. At high
levels, such as may occur through exposure from an industrial
accident, hydrogen fluoride may also damage the heart.
How likely are fluoride, hydrogen fluoride, and
fluorine to cause cancer?
Most of the studies of people living
in areas with fluoridated water or naturally high levels of
fluoride in drinking water did not find an association between
fluoride and cancer risk. Two animal cancer studies were inconclusive.
The international Agency for Research on Cancer (IARC) has
determined that the carcinogenicity of fluoride to humans
is not classifiable.
How does fluoride, hydrogen fluoride, and fluorine
When used appropriately, fluoride is
both safe and effective in preventing and controlling cavities.
Drinking or eating excessive fluoride during the time teeth
are being formed (before 8 years of age) can cause visible
changes in teeth. This condition is called dental fluorosis.
At very high concentrations of fluoride, the teeth can become
more fragile and sometimes can break.
No studies have addressed whether low
levels of fluoride will cause birth defects in humans. Birth
defects have not been found in most studies of animals.
How can families reduce their risk for exposure to
fluoride, hydrogen fluoride, and fluorine?
In the home, children may be exposed
to high levels of fluorides if they swallow dental products
containing fluoridated toothpaste, gels, or rinses. Parents
should supervise brushing and place at most, a small pea size
dab of toothpaste on the brush and teach children not to swallow
dental products. People who live in areas with high levels
of naturally-occurring fluoride in the water should use alternative
sources of dinking water, such as bottled water.
Is there a medical test to show whether I've been
exposed to fluoride, hydrogen fluoride, and fluorine?
Tests are available to measure fluoride
levels in urine; these tests can determine if you have been
exposed to higher-than normal levels of fluorides. The urine
test must be performed soon after exposure because fluoride
that is not stored in bones leaves the body within a few days.
The test cannot be performed in the doctor's office, but can
be done at most laboratories that test for chemical exposure.
The urine fluoride test cannot be used to predict the nature
or severity of toxic effects. Bone sampling can be done in
special cases to measure long-term exposure to fluorides.
Has the federal government made recommendations to
protect human health?
The EPA has set a maximum amount of fluoride
allowable in drinking water of 4.0 milligrams per liter of
water (4.0 mg/L). For the prevention of dental decay, the
Public Health Service (PHS) has, since 1962, recommended that
public water supplies contain between 0.7 and 1.2 milligrams
of fluoride per liter of drinking water.
The Occupational Safety and Health Administration
(OSHA) has set limits of 0.2 milligrams per cubic meter (0.2
mg/m3) for fluorine, 2.0 mg/m3 for hydrogen fluoride,
and 2.5 mg/m3 for fluoride in workroom air to protect
workers during an 8-hour shift over a 40-hour work week.
Agency for Toxic Substances and Disease Registry (ATSDR). 2003. Toxicological Profile for Fluorine, Hydrogen Fluoride, and Fluorides. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
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
Office of Innovation and Analytics, Toxicology Section
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.