Source: https://learn.aiacontracts.com/, December 20, 2022

The short answer is that typically the Owner is responsible for dealing with hazardous materials encountered on site. The primary justification for this allocation of risk is that the Owner, through its acquisition of the property and/or on-going ownership of the property, has had the unique opportunity to investigate the site and determine if there were any hazardous material present. Additionally, because identification and remediation of hazardous materials requires special procedures, equipment, and licensing, it is inappropriate for a typical construction contractor to bear responsibility for identifying and handling hazardous materials. Read more.