What the search actually did
It compared the property's location against historical mapping and records of potentially contaminative land uses, and reported proximity. “On or near” covers a radius, so a result can be triggered by something that was never on your plot at all.
Nobody has taken a sample. An adverse result is a prompt for further enquiry or for insurance; it is not evidence that anything is in the ground, and the absence of one is not evidence that nothing is.