Phase II Environmental Site Assessment

What is a Phase II ESA?

A Phase II ESA is a quantitative assessment that samples and analyzes the soil, soil vapor, and/or groundwater of a property, typically helping to determine whether there is a presence or absence of hazardous substances and petroleum products on site.

When environmental due diligence goes beyond the scope of a Phase I ESA, a Phase II Environmental Site Assessment may be necessary to further evaluate the potential of contamination at the subject property.

Once AEI completes the field investigation, a state-certified laboratory will conduct sample analyses of potential contaminants. AEI will then prepare a report signed by a state-designated professional geologist or engineer that details the analytical laboratory data and field investigation conclusions, along with any recommendations.

Phase II ESAs typically follow applicable state or regional regulatory guidance and applicable ASTM standards. The Phase II ESA aids in the determination of the health, environmental, and business risk at a site based on the type of contaminant, concentration levels, media impacted, location, regional regulatory guidelines, and type of property. AEI’s team of experienced professionals understands and can interpret your risks to help you navigate all considerations.

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What is the difference between a Phase I and Phase II ESA?

A Phase I ESA conducts research to determine if there are any environmental risks that may be associated with the property. This process includes site and area reconnaissance and utilizes resources like government and agency databases, historical site records, interviews, site plans, and photographs, as well as other types of documents that shed light on the current and past uses of the property. The Phase I ESA’s main goal is to identify Recognized Environmental Conditions.

The Phase II Environmental Site Assessment is often conducted in response to a Recognized Environmental Condition identified in Phase I ESA. Where the Phase I includes record research and visual site inspections, the Phase II ESA will typically include site-specific testing, including limited surface and subsurface sampling of soil, groundwater and/or vapor. Soil, groundwater and soil gas samples are collected and analyzed for hazardous and non-hazardous material contamination, inclusive of petroleum, solvent, metals and other chemicals, as applicable, based on the information presented in the Phase I ESA.


When is a Phase II ESA ordered?

A Phase II ESA may be ordered for any number of reasons, primarily when the findings of the Phase I ESA result in open issues or questions that can be answered by a Phase II ESA investigation. A Phase II is often conducted prior to the purchase or transfer of a property, allowing the purchaser to make an informed decision about the identified risks associated with the property. A Phase II ESA may also be conducted as a follow-up to the Phase I ESA to satisfy requirements of the “innocent landowner defense,” liability against responsibility for cleaning up the impacted property(ies), or for any adverse human health impacts or devaluations of the subject property or nearby properties.

Typically, a Phase II is ordered when a Phase I ESA indicates a recognized environmental condition or that conditions exist that indicate the potential presence of environmental contaminants on the property or on a nearby site that could negatively impact human health, the property itself, exceed an applicable regulation, potentially impact the value of the property, or impede redevelopment. Many lenders automatically require a Phase II ESA if the property has a history of environmentally sensitive uses that present a potential risk of contamination, even though there is no direct evidence of impact.

A Phase II can always be ordered without conducting a Phase I ESA. This Phase II is often performed when financing is not the driver for the Phase II but where conditions are suspect for contamination or are unknown.


How much does a Phase II ESA cost?

Costs can vary and are dependent upon property location, the complexity of the site’s history, its uses, and results of the Phase I ESA. Typical Phase IIs can cost anywhere between $5,000 to $20,000 for a small acreage property with likely limited potential contamination. However, based on the nature of the investigation, potential contaminants, sensitive uses/receptors associated with the property or the property area, complexity of the site and its use and history and the complexity of tests and the methods needed to collect and analyze samples, the price of the Phase II can easily exceed the $20,000 amount. Extensive proposals are prepared to outline scopes of work and associated pricing.


What is included in a Phase II ESA?

Phase IIs vary in scope but typically follow state and regional guidelines and applicable ASTM standards. Site conditions and environmental issues can vary widely, which results in differing scopes of work.

AEI offers customized Phase II ESAs generally based on the following factors, as applicable:

    • The property’s historical and current operations
    • Known or suspected hazardous releases
    • Potential risks to the environment, human health or
    • to the property structures or values
    • Client’s risk tolerance
    • Sampling locations
    • Depths of drilling
    • Analytical criteria
    • Field investigation methodologies
    • Reporting values

No matter the scope, all Phase II ESAs must generally follow current ASTM standards as well as applicable, state and local regulatory oversight agency procedures. This also includes applicable health and safety guidelines and permitting as required by local, state, and federal environmental agencies.

What Type of Work is Performed in a Phase II ESA?

Records Review

This begins with a review of historical land use and geological conditions, as well as data from the Phase I ESA or applicable information including property use, processes and products produced.


An environmental professional develops a plan or scope of work to evaluate the potential of contamination to help determine the sources and potential exposure pathways. An OSHA-compliant health and safety plan (HASP) is prepared for the project, summarizing all possible fieldwork hazards. Planning typically includes a site walk and does include an associated local and private utility clearances.

Identification Chemicals of Concern

Determine any contaminants that are likely present in soils, groundwater or vapors based on current and historic uses or the property and nearby off-site properties.

Media Sampling

Sample indoor air, soil, soil vapor, and/or groundwater, as applicable. Collect and analyze samples to determine the type and presence of contaminants/chemicals of concern in areas likely to be impacted. Select samples are then preserved and packaged at the site and transported under chain-of-custody to a state licensed laboratory for analyses. Samples undergo chemical analyses in a laboratory. The data and site activities are evaluated. Laboratory data is then compared to regulatory standards and screening levels.

Further Investigation of Areas of Concern

Review the laboratory results of sampling and encountered conditions to evaluate any high-risk areas and the need, if any, for additional testing. If necessary, additional investigative next steps are developed to prevent and minimize exposures to encountered contamination.


Subsequent to the completion of the field work, the data collected during the Phase II process is presented typically in a report. The report presents the Site history, the nature of concerns including the chemicals of concern, methods and field activities used, limitations, samples collection rationale, analytical data and a summary of results, including a comparison to applicable regulatory data. Conclusions and recommendations are often offered. Reports are typically shared with the client, only, unless sharing of data is required under state or permit mandate.

Regulatory Reporting and Coordination

Typically this beyond the scope of a Phase II but may necessary based on the results of the Phase II. These activities are typically performed with concurrence of the client, unless it is required by state statutes. The client is made aware of any state or permit requirements as part of the initial proposal process.


Why do I need a Phase II Environmental Site Assessment?

There are a few reasons for ordering a Phase II ESA such as:

    • If a Phase 1 Environmental Site Assessment revealed the potential or known presence of hazardous materials,
    • To evaluate the health and safety of the property occupants as well as the potential of on or off-site contamination impacting both your environmental and business risk to your property or your neighbor,
    • To gain financing, many banks require a Phase II ESA company to review the property for risk of environmental contaminants before approving a loan, especially if that property has a history of environmentally sensitive uses.
    • If you own, or are buying a property, that may be impacted by contaminants of concern.
    • Or if you an operating or are a responsible party for processes that might impact or have impacted the property or human health or the environment with contaminants of concern.
Who can perform a Phase II ESA?

An environmental professional or state licensed personnel must oversee the assessment. All field staff must have yearly applicable OSHA training and medical clearance.

How long does a Phase II assessment take?

On average, the total time can take about four weeks.

What is included in a Phase II ESA?

Because each property and its needs vary, there is no standard Phase II ESA that can be applied across the board. However, it commonly involves hands-on testing, including limited surface and subsurface sampling of soil, groundwater and/or vapor. Samples are collected and analyzed then compared to applicable regulatory standards to evaluate the type, presence and initial severity or areas of concern of contaminants. Areas of concern are further investigated, and a plan is developed for further evaluation or cleanup if necessary.

How long is a Phase II ESA good for?

Phase II Environmental Site Assessments are good so long as the rules and regulations under which they were performed remain a current and applicable state statute.Different state and local agencies may have different requirements for the shelf life of the Phase II data collected and reported. Therefore, consulting with an environmental professional geologist is recommended.

If the Phase II Environmental Site Assessment reveals the presence of a concern, it may be recommended that the site and contaminants be further characterized via additional Site Investigation. Through our well-established and longstanding relationships with local and state regulatory oversight agency personnel, AEI will craft creative solutions to achieve site closure and meet your needs as the property owner, while satisfying the agency’s mandate to protect human health and the environment.

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