How Exposure Occurs

• Routes of exposure to biological warfare agents: Exposure is most likely to occur when victims breathe (inhalation) biological agents released into the air (aerosols). Very tiny particles are inhaled most efficiently into the lungs. Mucous membranes or breaks in the skin also are vulnerable and require protection against biological warfare agents. However, skin contact does not pose a significant risk, because intact skin provides an effective barrier to all biological agents except trichothecene mycotoxins. Insignificant amounts of aerosolized particles stick to clothing or skin. It is difficult to get particles into the air once they have been released and landed (this is called secondary aerosolization). People are sometimes exposed by ingestion, which may occur with hand-to-mouth contact or by swallowing contaminated secretions. Follow these eMedicine links to anthrax, smallpox, and plague to learn more.
  
  
• Routes of exposure to chemical warfare agents: Exposure to chemicals and chemical warfare agents occurs by inhaling chemical gas or vapor. Exposure also occurs by direct contact of the eyes or skin to chemical vapor or liquid. Mucous membranes are particularly vulnerable, because moisture promotes the absorption of many chemicals. Ingestion is a minor route of exposure. Follow this eMedicine link to chemical warfare to learn more.
  
  
• Routes of exposure to radioactive agents: People exposed to beams of ionizing radiation (for example, patients receiving diagnostic x-rays) do not emit radiation and therefore pose no radiation danger to others. In the setting of an explosion, fire, or spill of radioactive material, however, victims can become contaminated with radiation-emitting material. External contamination occurs when radioactive material gets on a victim's clothing, skin, or hair. Victims also can become contaminated internally if radioactive material enters the body through the gastrointestinal tract, an open wound, or, less likely, inhalation of highly radioactive dust. In any situation, the goal of personal protective equipment is to prevent the transfer of radioactive material from the victim to the rescuer until the victim is decontaminated.