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Frequent Questions

Below you can find clear answers to common questions about the following subjects:

About Radiation and Radioactivity 

What is radiation?

Radiation is energy given off by atoms in the form of particles or electromagnetic rays. There are actually many different types of electromagnetic radiation that have a range of energy levels. They form the electromagnetic spectrum and include radio and micro waves, heat, light, and x-rays. However, when you see the word 'radiation' on this Website, we refer to 'ionizing radiation,' (radiation that has enough energy to break chemical bonds).

What is radioactivity?

The radioactivity of a material is the property of emitting radiation. 

Is all ionizing radiation the same?

No. Ionizing radiation can be in the form of particles or rays, and each form behaves differently. The kind of radiation given off by a nucleus depends on the nature of the imbalance in the nuclear forces.

more information Understanding Radiation
  Why are Some Atoms Radioactive: Is All Radiation the Same?
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About Sources of Radiation

Where am I likely to encounter radioactive materials?
We encounter radiation from numerous sources: the atmosphere, soil and water, food, and even our own bodies. Many of the sources we encounter are shielded to prevent exposure. For example, a small amount of radioactive material is used in ionizing technology smoke detectors. It is sealed in a chamber and surrounded by a housing to prevent contact. However, we may encounter other sources, such as naturally occurring radon or uranium mill tailings which are not shielded and require us to take protective measures
How can people be exposed to radiation?

Each of the different routes, or pathways, by which people can be exposed to radiation result in exposure to different parts of the body. When calculating exposures or estimating the effects of exposures, health physicists analyze the three exposure pathways:  inhalation, ingestion, and direct (external) exposure 

more information Exposure Pathways  
  Becoming Aware of Radiation Sources  
  Information from the Food and Drug Administration 
Overview of Electronic Product Radiation Control Laws and Regulations 
Electronic Product Radiation Control
  
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What is the most common naturally occurring radionuclide in the human body?

Potassium-40 is the most common. It is found in potassium-rich foods such as bananas (the most common source.)

more information Becoming Aware of Radiation Sources: Naturally Occurring Radiation
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About the Health Effects of Radiation

How does radiation cause health effects?

Living tissue in the human body can be damaged by ionizing radiation. The body attempts to repair the damage, but sometimes the damage is too severe or widespread, or mistakes are made in the natural repair process. 

How do we know radiation causes cancer?

At first it was learned through observation. As early as 1910-1912, radiation was known to cause skin cancer. As the uses of radiation became more widespread, and their apparent effects better documented, scientists conducted careful studies of people exposed to radiation. Among the best known long-term studies are those of Japanese atomic bomb blast survivors, other populations exposed to nuclear testing fallout (for example, natives of the Marshall Islands), and uranium miners.

Is any amount of radiation safe?

The effects of very low levels of ionizing radiation are very difficult to study. They are well below the levels of normal background radiation that people receive from natural sources. In fact, the conclusions about the effects of low levels of radiation come from what we learned about the effects of higher levels of radiation exposure. As a result, there is no firm basis for setting a "safe" level of exposure above background. 

Most regulatory and advisory bodies around the world (including EPA) assume that any exposure carries some risk and that the risk increases as the exposure increases.

more information Health Effects
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About EPA's Radiation Protection Program

How does EPA protect people from radiation?

EPA carries out its radiation protection program responsibilities with several key, complementary activities:

  • setting protective limits on radioactive emissions and associated risks to public health and the environment
  • assessing radiation risk
  • responding to emergencies involving radioactive materials
  • communicating – providing information and inviting participation in radiation exposure protection programs
  • working cooperatively with industry, the states, other federal agencies, and national and international organizations that have radiation protection responsibilities.
Why does EPA have a radiation protection program?

Congress gave EPA the responsibility and authority to develop and issue standards, regulations, and guidance to protect people and the environment from harmful exposure to radiation EPA is the primary Federal agency charged with protecting people and the environment from harmful and avoidable exposure to radiation.

Do other organizations have radiation protection responsibilities?

Yes, federal, state, and local governments, as well as tribal organizations play important roles in radiation protection. International organizations, such as the International Atomic Energy Agency also play a role.

more information Protecting People and the Environment
  About EPA's Radiation Protection Program
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