Did people come into contact with the contamination?
We need to find evidence that people had some contact with the contaminant by touching, breathing or ingesting it.
For example, it is possible that contamination existed in the community's groundwater. However, no one drank the water, touched the water, or breathed water vapor. Instead all water supplied to residents in the community came from surface water collected in the mountains far away from the community.
By looking at those various issues, we can determine if, in fact, people came into contact with contamination. If that occurred, we have what is known as "completed exposure pathway."