ToxFAQs™ for Cobalt
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This fact sheet answers the most frequently
asked health questions about cobalt. 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. It is important you understand this information 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.
The general population is exposed to low levels of cobalt in air, water, and food. Cobalt has both beneficial and harmful effects on health. At low levels, it is part of vitamin B12, which is essential for good health. At high levels, it may harm the lungs and heart. This chemical has been found in at least 426 of the 1,636 National Priorities List sites identified by the Environmental Protection Agency (EPA).
What is cobalt?
Cobalt is a naturally occurring element
found in rocks, soil, water, plants, and animals. Cobalt is
used to produce alloys used in the manufacture of aircraft
engines, magnets, grinding and cutting tools, artificial hip
and knee joints. Cobalt compounds are also used to color glass,
ceramics and paints, and used as a drier for porcelain enamel
Radioactive cobalt is used for commercial
and medical purposes. 60Co (read as cobalt sixty) is used
for sterilizing medical equipment and consumer products, radiation
therapy for treating cancer patients, manufacturing plastics,
and irradiating food. 57Co is used in medical and scientific
research. It takes about 5.27 years for half of 60Co to give
off its radiation and about 272 days for 57Co; this is called
What happens to cobalt when it enters the environment?
- Cobalt enters the environment from natural sources and
the burning of coal or oil or the production of cobalt alloys.
- In the air, cobalt will be associated with particles that
settle to the ground within a few days.
- Cobalt released into water or soil will stick to particles.
Some cobalt compounds may dissolve.
- Cobalt cannot be destroyed. It can change form or attach
to or separate from particles. Radioactive decay is a way
of decreasing the amount of radioactive cobalt in the environment.
How might I be exposed to cobalt?
- You can be exposed to low levels of cobalt by breathing
air, eating food, or drinking water. Food and drinking water
are the largest sources of exposure to cobalt for the general
- Working in industries that make or use cutting or grinding
tools; mine, smelt, refine, or process cobalt metal or ores;
or that produce cobalt alloys or use cobalt.
- The general population is rarely exposed to radioactive
cobalt unless a person is undergoing radiation therapy.
However, workers at nuclear facilities, irradiation facilities,
or nuclear waste storage sites may be exposed to radiation
from these sources.
How can cobalt affect my health?
Cobalt can benefit or harm human health.
Cobalt is beneficial for humans because it is part of vitamin
Exposure to high levels of cobalt can
result in lung and heart effects and dermatitis. Liver and
kidney effects have also been observed in animals exposed
to high levels of cobalt.
Exposure to large amounts of radiation
from radioactive cobalt can damage cells in your body from
the radiation. You might also experience acute radiation syndrome
that includes nausea, vomiting, diarrhea, bleeding, coma,
and even death. This would be a rare event.
How likely is cobalt to cause cancer?
Nonradioactive cobalt has not been found
to cause cancer in humans or animals following exposure in
food or water. Cancer has been shown, however, in animals
that breathed cobalt or when cobalt was placed directly into
the muscle or under the skin. Based on the laboratory animal
data, the International Agency for Research on Cancer (IARC)
has determined that cobalt and cobalt compounds are possibly
carcinogenic to humans.
Exposure to high levels of cobalt radiation
can cause changes in the genetic materials within cells and
may result in the development of some types of cancer.
How can cobalt affect children?
We do not know whether children differ
from adults in their susceptibility to cobalt. However, it
is likely that health effects in children would be similar
those in adults. Studies in animals suggest that children
may absorb more cobalt than adults from foods and liquids
We do not know if exposure to cobalt
will result in birth defects or other developmental effects
in people. Birth defects have been observed in animals exposed
to nonradioactive cobalt. Exposure to cobalt radiation can
also result in developmental effects.
How can families reduce the risk of exposure to cobalt?
Children should avoid playing in soils
near hazardous waste sites where cobalt may be present.
Is there a medical test to show whether I've been exposed to cobalt?
Cobalt levels can be tested in the urine
and blood within a couple of days of exposure. Your doctor
can take samples, but must send them to a laboratory to be
tested. The amount of cobalt in your blood or urine can be
used to estimate how much cobalt you were exposed to. However,
these tests cannot predict whether you will experience any
Two types of tests are available for
radioactive cobalt. One is to see if you have been exposed
to a large dose of radiation, and the other is to see if radioactive
cobalt is in your body. The first looks for changes in blood
cell counts or in your chromosomes that occur at 3 to 5 times
the annual occupational dose limit. It cannot tell if the
radiation came from cobalt. The second type of test involves
examining your blood, feces, saliva, urine, and even your
entire body. It is to see if cobalt is being excreted from
or remains inside your body. Either the doctor's office collects
and sends the samples to a special lab for testing, or you
must go to the lab for testing.
Has the federal government made recommendations to
protect human health?
The Occupational Safety and Health Administration
(OSHA) has set a limit of 0.1 milligrams of nonradioactive
cobalt per cubic meter of workplace air (0.1 mg/m3) for an
8-hour workday and 40-hour work week.
The Nuclear Regulatory Commission limits
radioactive cobalt in workplace air to 1x10-5 microcurie per
milliliter (µCi/mL) for 57Co and 7x10-8 µCi/mL for 60Co. EPA
has set an average annual drinking water limit of 1000 picocurie
per liter (pCi/L) for 57Co or 100 pCi/L for 60Co so the public
radiation dose will not exceed 4 millirem.
Agency for Toxic Substances and Disease
Registry (ATSDR). 2004. Toxicological
Profile for cobalt. 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.