Answer to Question #5592 Submitted to "Ask the Experts"

How would you define "secondary exposure" and "secondary contamination"? I am working on the development of an awareness-level all-hazards course for emergency first responders (physicians, RNs, firefighters, police, public health personnel, EMTs, etc.) We want to include one of the two terms above in the glossary, but are having trouble finding or crafting a comprehensive, yet not overly technical, definition. These terms are not currently in the HPS glossary—can you help?

I am not aware of any formally approved definitions for these terms, although I believe they each have meanings that are generally accepted by the radiation protection community, although the first term (secondary exposure) has at least a couple of different definitions, depending on the situation. As commonly used, I would suggest something like the following possible definitions.

Secondary exposure: This term often refers to exposure to a different individual from radiations emitted by radioactive contamination on or in another individual; the term may also refer to radiation exposure of a given part of an individual's body as a result of radiation emitted from contamination on or in some other part(s) of the individual's body.

(In an alternative definition, the term secondary radiation exposure sometimes refers to exposure from secondary radiations that are produced by interactions of primary radiations—e.g., scattered photons produced by Compton interactions of primary photons or gamma radiation produced by capture of neutrons by nuclei.)

Secondary contamination: This generally refers to radioactive contamination that has been transferred from one location to another, such as from hands to face or from a contaminated tool or from contaminated protective gear to one's skin; it can also refer to transfer from a contaminated individual to a second individual. Secondary contamination is often referred to as cross-contamination.

Hope this is helpful.

George Chabot, PhD, CHP