ToxFAQs™ for Cesium
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This fact sheet answers the most frequently
asked health questions about cesium. 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.
Exposure to stable
or radioactive cesium occurs from ingesting contaminated
food or drinking water or breathing contaminated air.
High levels of radioactive cesium in or near your body
can cause nausea, vomiting, diarrhea, bleeding, coma,
and even death. This may occur after nuclear accidents
or detonation of atomic bombs. Stable (non-radioactive)
cesium has been found in at least 8 of the 1,636 National
Priority List (NPL) sites identified by the Environmental
Protection Agency (EPA). Radioactive cesium has been found
in at least 23 of the 1,636 NPL sites identified by the
What is cesium?
Cesium is a naturally occurring element
found combined with other elements in rocks, soil, and dust
in low amounts. Naturally occurring cesium is not radioactive
and is referred to as stable cesium. There is only one stable
form of cesium naturally present in the environment, 133Cs
(read as cesium one-thirty-three).
Nuclear explosions or the breakdown of
uranium in fuel elements can produce two radioactive forms
of cesium, 134Cs and 137Cs. Both isotopes decay into non-radioactive
elements. 134Cs and 137Cs generate beta particles as they
decay. It takes about 2 years for half of 134Cs to give off
its radiation and about 30 years for 137Cs; this is called
What happens to cesium when it enters the environment?
- Cesium in air can travel long distances before settling
to the ground or water.
- Most cesium compounds dissolve in water.
- In moist soils, most cesium compounds are very soluble.
- Cesium binds strongly to moist soils and does not travel
far below the surface of the soil.
- Radioactive decay is a way of decreasing the amount of 134Cs and 137Cs in the environment.
How might I be exposed to cesium?
- You can be exposed to low levels of stable or radioactive
cesium by breathing air, drinking water, or eating food
- Food and drinking water are the largest sources of exposure
- You can be exposed to radioactive cesium if you eat food
that was grown in contaminated soil, or if you come near
a source of radioactive cesium.
- Working in industries that process or use natural cesium
or cesium compounds.
- Living near uncontrolled radioactive waste sites containing
How can cesium affect my health?
It is highly unlikely that you would
be exposed to high enough amounts of stable cesium to cause
harmful health effects. Laboratory animals given very large
amounts of cesium compounds showed changes in behavior, such
as increased or decreased activity.
Exposure to large amounts of radioactive
cesium can damage cells in your body from the radiation. You
might also experience acute radiation syndrome, which includes
nausea, vomiting, diarrhea, bleeding, coma, and even death
in cases of very high exposures.
How likely is cesium to cause cancer?
There are no studies regarding non radioactive
cesium and cancer. There are no human studies that specifically
associate exposure to radioactive cesium with increased cancer
Because radioactive cesium emits ionizing
radiation, carcinogenic effects similar to those observed
in Japanese survivors of the atomic bombing incidents might
be expected among individuals acutely exposed to very high
levels of radiation from a radioactive cesium source.
Rats exposed to high doses of radiation
from 137Cs had increased risk of mammary tumors. Older rats
seemed more resistant than younger ones.
How does cesium affect children?
Children can be affected by cesium in
the same ways as adults. Infants born to atomic bomb survivors
exposed to high doses of ionizing radiation while pregnant,
showed later signs of decreased mental abilities.
Exposure to the radiation from radioactive
cesium has caused birth defects in animals.
How can families reduce the risk of exposure to cesium?
Since cesium is naturally found in the environment, we cannot avoid being exposed to it. However, these relatively low amounts do not warrant immediate steps to reduce exposure. In the unlikely case that you are exposed to high levels of radioactive cesium because of accidental release at a nuclear plant or a nuclear weapon has been detonated, follow the advice of public health officials who will publish appropriate guidelines for reducing exposure.
Is there a medical test to show whether I've been exposed to cesium?
Two types of tests are available for
radioactive cesium. One is to see if you have been exposed
to a large dose of radiation, and the other is to see if cesium
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 cesium. The second type of test involves examining
your blood, feces, saliva, urine, and even your entire body.
It is to see if cesium is being excreted from or remains inside
your body at levels that are higher than normal. 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 National Institute for Occupational
Safety and Health (NIOSH) recommends a limit of 2 milligrams
of cesium hydroxide per cubic meter of air (2 mg/m3) as an
average for a 10-hour workday, 40-hour workweek.
The EPA has established a maximum contaminant
level of 4 millirem per year for beta particles and photon
radioactivity for man-made radionuclides (including radioactive
The Nuclear Regulatory Commission (NRC)
has set limits for radioactive cesium in workplace air of
4x10-8 microcurie per milliliter (µCi/mL) for 134Cs
and 6x10-8 µCi/mL for 137Cs. EPA has set an average
annual drinking water limit of 80 picocurie per liter (pCi/L)
for 134Cs or 200 pCi/L for 137Cs so the public radiation dose
will not exceed 4 millirem.
Agency for Toxic Substances and Disease
Registry (ATSDR). 2004. Toxicological
Profile for Cesium. 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.