Phase I Environmental Site Assessment is a specialized skill that involves conducting a thorough investigation and evaluation of a property to identify potential environmental issues that may impact its use or value. This may include reviewing historical records, conducting site inspections, and sampling soil, water, and air to identify potential contaminants. The goal of the assessment is to identify potential environmental liabilities and provide recommendations for further investigation, remediation, or mitigation measures. It requires specialized knowledge and training in environmental regulations, contaminant behavior, hydrogeology, and risk assessment.