Chemical Agents of Opportunity for Terrorism: TICs & TIMs

Chemical Agents of Opportunity for Terrorism
Training Support Package
Participant Guide
Slide 17
One way to differentiate the potential effects of external radiation is by their ability to
penetrate the body.
Alpha particles do not penetrate even the dead layer of skin and can be stopped by a
thin layer of paper or clothing. However, if one ingests or inhales an alpha emitting
radioactive material the radiation can cause damage to the tissue it is next to, such as
the lung cells.
Beta particles are only moderately penetrating, though energy varies by the element.
Some beta radiation can penetrate human skin to the layer where new skin cells are
produced. If beta emitting contaminants remain on the skin for a prolonged period of
time, they may cause skin injury resembling sunburn. They may also be harmful if
deposited internally.
Gamma rays and x-rays are able to travel into or through human tissue (thus the use of
x-rays in medical imaging). Lead is needed to stop these.
Neutrons also penetrate most materials. They are able to travel many feet in concrete,
yet may be stopped by large amounts of water. Neutrons are not likely to be
encountered in dirty bomb events, but would be seen after a nuclear bomb detonation.
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