Ionizing radiation

Polonium-210: basic facts and questions

The investigation of the polonium poisoning case in United Kingdom has brought attention to the radioactive material Polonium-210 (Po-210) as a possible public health concern. The United Kingdom's Health Protection Agency has information about Po-210 and this event on its web site.

The World Health Organization's Department of Public Health and Environment has prepared the following information about Polonium-210.

Basic facts about Polonium-210

Po-210 is a naturally occurring radioactive material. It is found in very low concentrations in the environment as a part of the uranium decay chain and can be derived from lead-containing wastes from uranium, vanadium, and radium refining operations - however, not in significant quantities. It may be also produced artificially, which requires fairly sophisticated equipment used in the nuclear industry.

Po-210 emits alpha particles and is 5,000 times more radioactive than radium. The half-life of Po-210 is 138 days. Alpha radiation delivers a large amount of energy to living cells and can cause considerable damage and cell death. Alpha particles lose most of their energy on impact, and cannot move further into matter, hence alpha radiation does not penetrate through surfaces (e.g. paper, human skin or clothes).

Po-210 is used in some industrial applications such as static eliminators, which are devices designed to eliminate static electricity in processes such as rolling paper, manufacturing sheet plastics, and spinning synthetic fibers. It is also used in nuclear weapons production, as a power supply in small satellites, and in the oil industry.

Health risk of Po-210

Po-210 represents a radiation hazard only if taken into the body – by inhalation, ingestion, or getting into a wound. This “internal contamination” can cause irradiation of internal organs, which can result in serious medical symptoms or death. The toxicity of Po-210 is much higher than that of cyanides, for example. Nevertheless it does not represent a risk to human health as long as it remains outside the body. Most traces of it can be eliminated through careful hand-washing and showering, or washing machine and dishwasher cycles.

People who come into contact with a person contaminated by Po-210 will not be exposed to radiation (irradiated) simply by being in the proximity of this person, unless they ingest or inhale bodily fluids of the contaminated person. For the general public, normal hygiene measures (such as thorough washing of hands and washing of fruit/vegetables before consumption) are sufficient.

For more information about contamination and irradiation (exposure) see the fact sheet Radiological Contamination and Radiation Exposure prepared by the US Center for Disease Control.

What should you do if you have concerns about possible exposure related to the London incident?

If you were visiting London during early November 2006 and think you might have had contact with persons or locations involved in the polonium incident, see Send e-mail requesting information to the U.K. Health Protection Agency at If you have concerns about your health, contact your physician.


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