Phase I & II Environmental Site Assessments

You’ve finally found a property for your business, or to add to your portfolio. You want to find out about historical occupants or operations that might have affected environmental quality. If you don’t find out about on-site contamination before you buy, you’ll be stuck with all the costs and all the liability associated with it once you own it. Simply put: you need a Phase I Environmental Site Assessment, or ESA.

HSA Golden has performed countless Phase I and II ESAs to address exactly this unknown. These assessments are essentially a “baseline physical,” an evaluation of past and present conditions at and near the property which may indicate the presence of contamination.


HSA Golden’s Phase I ESAs are performed in accordance with ASTM E1527-21 and EPA’s All Appropriate Inquiries Final Rule, 40 CFR Part 312. The specific purpose of a Phase I ESA is to identify Recognized Environmental Conditions (RECs) associated with the site. ASTM defines a REC 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 future release to the environment.

The Phase I ESA includes a review of readily available information, such as historical aerial photographs, environmental databases, and previous property ownership, combined with a reconnaissance of the site and surrounding area. If RECs are identified when performing a Phase I ESA, and it is unknown whether these RECs have negatively impacted soil, surface water, groundwater, or sediment, a Phase II ESA is typically recommended.


While every site is different, most Phase II ESAs will involve collection of some kind of sample(s) for chemical analysis from the medium (or media) suspected to be impacted by contamination. Samples can be collected via various methodologies that include, but are not limited to, drilling soil borings (either using hand-operated or machine-operated equipment), installation of groundwater monitoring wells, installation of soil gas probes, or direct collection of air/gas samples. HSA Golden’s staff are fully equipped with an extensive assortment of sampling equipment and instrumentation to collect any samples that may be needed to perform even the most complex Phase II ESA. All samples collected are chemically analyzed by laboratories certified to perform the analyses in the particular state where the samples are collected.

HSA Golden personnel also carefully review the laboratory analytical data we collect and compare the reported concentrations to applicable regulatory criteria. If contaminant concentrations exceed regulatory limits, recommendations for additional testing may be made, to determine the extents of the contamination. This information is needed before an estimate of cleanup costs can be accurately predicted and is critical in making informed decisions as to whether to proceed with purchasing a property. For example, knowing the extent of petroleum-impacted soil or groundwater at a site will factor heavily when negotiating the selling price and the terms of the sale.


Hiring the right environmental engineering consulting firm to perform a Phase I or Phase II ESA is just as important as having an experienced doctor perform a physical examination. You want to make sure you know as much as possible about a property and all the potential risks associated with it prior to closing. Whether the property is half an acre or 100,000 acres, an agricultural site or an enormous factory, our team of professionals at HSA Golden are ready to assist you with your project.