Never assume a property’s soil and groundwater are clean because any releases that may have occurred occurred long ago and have probably “washed away.” Certain subsurface conditions either contribute to or hinder the natural attenuation of contaminant concentrations. However, it’s not at all uncommon to discover gross contamination from releases that occurred 30, 40, 50 and more years ago. A Phase I Environmental Site Assessment is only a speculative judgment and not scientific certainty. Testing is knowing.