What is a Phase I Environmental Site Assessment (ESA) and who needs one?

A Phase I ESA is an environmental due diligence assessment of a parcel of real estate, a portion thereof (e.g. a condominium), or even a business entity. Phase I ESAs are generally performed on industrial and commercial real estate but can be performed for residential property in some cases. Phase I ESAs are generally performed prior to the transfer of ownership of a real estate parcel or business entity, or when the real estate is to be used as loan collateral. A thorough ESA by an experienced consultant is strongly advised to avoid unwanted liability.

The Phase I ESA process is an in-depth review of past and present uses of the site as it pertains to Recognized Environmental Conditions (RECs) and Historical Recognized Environmental Conditions (HRECs). Additionally, for Connecticut, an opinion is given based upon site use and waste generation history as to whether the site is to be classified as a hazardous waste "Establishment"* and required (in the event of a property transfer) to be entered into the Connecticut Department of Energy and Environmental Protection (CTDEEP) remediation program in accordance with the Property Transfer Law.

In accordance with industry standards (ASTM Practice E 1527-13 and the CTDEEP Site Characterization Guidance Document Rev. 12/2010), the following tasks are completed: interviews with current and past site owners and operators; site interior and exterior inspections and photography; municipal office file reviews; online database searches for environmental records related to the site and nearby properties; research at the Connecticut State Library to review historical aerial photographs, Sanborn Fire Insurance Maps, historical USGS Quadrangle Maps and historical street directories; and a visit to the CTDEEP public file room to review publicly available files related to possible HRECs/RECs at and near the subject site. The findings are summarized in a narrative report and an opinion is given on whether the site has any outstanding environmental regulatory compliance issues or HRECs/RECs. Such an opinion might include the recommendation for additional site investigation (e.g. Phase II ESA)*.

All ESA work at CCA is performed by or under the direct supervision of a Connecticut Licensed Environmental Professional (LEP)*. Please feel free to contact Mr. Ralph A. Klass P.E., L.E.P. at ralphklass@ccaengineering.com or 203-775-6207 if you would like to request a quotation for ESA services or if you have any questions regarding the services CCA can provide.


Recognized Environmental Concern (REC) – Can be defined as "the presence or likely presence of any hazardous substances or petroleum products in, on, or at a property: (1) due to release to the environment; (2) under conditions indicative of a release to the environment; or (3) under conditions that pose a material threat of a future release to the environment.

Historical Recognized Environmental Condition (HREC) – Refers to a past release that has been remediated to below "residential" standards and given regulatory closure with no use restrictions.

*See additional FAQ answer sheets for the definition of Hazardous Waste Establishment, Phase II ESA, Phase III ESA and Licensed Environmental Professional (LEP).