A Phase I Environmental Site Assessment (ESA) is a report prepared for a real estate holding that identifies potential or existing environmental contamination liabilities. It is completed to research the current and historical uses of a property as part of a commercial real estate transaction. The purpose of the report is to assess if current or historical property uses have impacted the soil or groundwater beneath the property and could pose a threat to the environment and/or human health. The actual sampling of soil, air, groundwater, and/or building materials is typically not conducted during a Phase I ESA. Instead, it typically includes a records review, site reconnaissance, interviews, and a report summarizing what concerns were identified on the property and making recommendations about what actions, if any, are needed to address these concerns. The standards for performing a Phase I site assessment have been promulgated by the US EPA and are based in part on ASTM in Standard E1527-13. If a Phase I ESA determines a likelihood of site contamination, a Phase II Environmental Site Assessment is conducted, which is an "intrusive" investigation that collects original samples of soil, groundwater, or building materials to analyze for quantitative values of various contaminants. A Phase III Environmental Site Assessment is an investigation involving remediation of a site.