An exposure pathway is "complete" only if all five pathway elements are present or can be assumed to be present.

An exposure pathway is "potential" if one or more of the five elements has not been identified, but the element could be present if the appropriate data were available to verify its presence.

People can be harmed only if they contact a chemical over time at levels high enough to cause adverse health effects.

Comparison values are used only to select chemicals for further evaluation.

The next section of the learning program explains how to estimate how much of a chemical enters a person's body and how that will affect the person's health.