Phase 2 Environmental Site Assessment 2

Phase 2 Environmental Site Assessment

A Phase 2 Environmental Site Assessment or a “Phase 2 Subsurface Investigation,” is a direct test of underground materials at a property, to check for the possibility of contamination. A Phase 2 Report is a continuation of the environmental due diligence effort and is in furtherance of a Phase I Environmental Site Assessment. In fact, the Phase 2 ESA scope of work is based on the environmental conditions of a prerequisite Phase 1 ESA. A Phase 2 Environmental Report follows ASTM Standards and requires the responsible charge of a professional geologist. To illustrate, Phase 2 ESAs typically include underground surveys, drilling, sampling, laboratory analysis, and complex risk modeling. Updated March 31, 2020.

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General Overview

Not all Phase 1 Environmental Site Assessments lead to a Phase 2 Subsurface Investigation. However, when a Recognized Environmental Condition (REC) or any other environmental issues or conditions are identified, the need for a Phase 2 ESA becomes apparent. And a Phase 1 ESA is the prerequisite to a Phase 2 Environmental Site Assessment. Thus, without a valid Phase 1 ESA to base on, a subsurface investigation cannot hold the title “Phase 2.”

Contamination Cleanup & Remediation

In some cases, significant contamination may exist at a site. If so, such contamination does come to light during the Phase II Environmental Investigation process. And if the apparent contamination exists at high-enough levels, it may warrant clean-up action, per the environmental agencies. In such a case, remediation is likely to be the next phase of action.

Recommendations for a Soil Management Plan

Often times during a Phase 2 Subsurface Investigation, existing soil contamination requiring future excavation becomes apparent. In such a case, the Phase II ESA report is likely to recommend a Soil Management Plan. This plan is a separate document from the Phase 2 Environmental Report and serves as a guideline for legally and efficiently excavating and replacing contaminated soil. Alternatively, this document applies to underground tank removal projects.

Key Components

Phase 2 Subsurface Investigations have many components. Each project starts with a thorough review of historical land-use and geological conditions. And each scope of work pertains to the site-specific details, meanwhile meeting the ASTM standards. Furthermore, an OSHA-compliant health and safety plan is prepared to summarize all fieldwork hazards, as well as the chemicals of concern. The fieldwork process comprises drilling and the sampling of soil, soil-gas, groundwater and indoor air. And after fieldwork, the samples undergo chemical analysis inside a laboratory. Subsequently, scientists examine the laboratory data and run complex vapor intrusion and human health risk models, against regulatory agency standards.

The Phase 2 ESA Objective

Ultimately, a Phase 2 Environmental Site Assessment aims to determine whether there’s a significant pollution concern or health issue at a property. However, a Phase 2 ESA has a limiting scope of work. To clarify, a Phase II Subsurface Investigation only intends to check whether contamination exists or not. It does not define the lateral and vertical extent of contamination. Therefore, if pollution is revealed, a Phase 2 Environmental Site Assessment is not likely to comprise enough data for a clean-up plan or estimate. In fact, a proper remediation scope and price quote requires knowing the complete extent of subsurface contamination. As a result, additional testing is necessary when contamination is found.

Phase II ESA Environmental Site Assessment Drilling via Hollow-Stem Auger

Phase II ESA Environmental Site Assessment Hollow-Stem Auger Drilling and Soil Sampling

Phase 2 Environmental Scope

In general, Phase 2 Environmental Site Assessments must follow ASTM and EPA standards, as well as the guidelines by State and local environmental agencies. Variable site conditions and environmental issues result in differing scopes of work. Thus, no two properties are the same. For instance, the drilling depths, sampling media and chemical analysis for a gas station Phase 2 ESA are likely to be dissimilar to a dry cleaner Phase 2 ESA.

Site-Specific Review & Scope Design

Geologists and engineers must prepare entirely new scopes of work for each Phase 2 ESA. Laboratory testing parameters are also site-specific and are a function of the land-use. Additionally, local regulations and standards play a role in the scope of work. For example, the San Francisco Regional Water Quality Control Board has differing contamination standards than the Los Angeles Regional Water Quality Control Board or the Texas Commission of Environmental Quality.

Environmental Permitting 

Environmental permitting is a general prerequisite to Phase 2 Subsurface Investigation fieldwork. For example, most projects within the Los Angeles County and Alameda County jurisdictions require a Well & Drilling Permit. The permit application process can add to the cost and turnaround time-frame of a Phase 2 ESA. In fact, some agencies can take up to ten business days to process drilling permits. Lastly, most drilling permits need closing out and require a closure report to verify all fieldwork abides by environmental laws and regulations.


In general, the fieldwork for a Phase 2 environmental project comprises a preliminary site walk, utility clearance marking, a geophysical survey, drilling, and sampling. The typical Phase II ESA includes approximately one to two full days of fieldwork onsite. And additional site visits may be necessary to remove hazardous waste.

Phase II Environmental Site Assessment Fieldwork

Phase II Environmental Site Assessment Fieldwork

Health & Safety

Health and Safety is an important pillar of the environmental engineering field. Drillers and geologists encounter numerous safety hazards on-site. For instance; heavy drilling rigs with pinch points, open boreholes, toxic chemicals in samples, etc. Thus, its a requirement for health and safety plans to be comprehensively reviewed by all field personnel before starting Phase 2 ESA fieldwork. The safety programs intend to prevent injuries from occurring at work and keep the project in compliance with labor laws and OSHA regulations. 

Geophysical Survey & Utility Clearance

Some Phase II Environmental Site Assessments also require a geophysical survey to delineate the extent of underground storage tanks, utility lines, and other subsurface anomalies. A geophysical survey takes place prior to sampling and applies electromagnetic and ground-penetrating radar technology to investigate subsurface conditions. Geologists review geophysical survey data prior to drilling, in order to design the Phase II ESA scope of work. Data and results control the quantity, frequency, location, and depths of the Phase 2 ESA samples. 

Using Ground Penetrating Radar for a Geophysical Survey During a Phase 2 Environmental Site Assessment

Geophysical Survey Ground Penetrating Radar During a Phase 2 Environmental Site Assessment

Drilling & Sampling

Under the supervision of a professional geologist, numerous boreholes are strategically advanced on a property. Modern drilling equipment (such as direct-push or hollow-stem auger drilling rigs) allows for the collection of discrete soil and groundwater samples. And driller can also construct soil-gas probes within boreholes, as a soil vapor sampling apparatus for geologists and chemists.   

Phase 2 Environmental Site Assessment Drilling Using Direct Push Methodology

Phase 2 Environmental Site Assessment Drilling via Direct-Push

Site Maps & Boring Logs

Informative site maps and soil boring logs are a necessary requirement of the Phase 2 ESA process. At a minimum, these figures document the location, depth, and purpose of each sample. Moreover, these figures demonstrate the sampling intervals, medias tested and methodology of the fieldwork. Site maps are to scale, and soil logging procedures conform to the Unified Soil Classification System. And these parts of the assessment occur in the field by a professional geologist.

Data & Analysis 

After fieldwork, samples undergo laboratory analysis by chemists, All laboratory methods are in accordance with EPA and ASTM method standards. Utilizing this data, geologists and engineers run risk assessment models and perform toxic vapor intrusion studies. The risk models also follow EPA and ASTM guidelines, as well as State and Federal standards. Human health risk models additionally comprise different functions for properties with residential land-use versus commercial land-use. In conclusion, the risk models evaluate whether there’s a health concern for occupants onsite, beyond a reasonable doubt. Similarly, toxicologists prepare indoor air quality and inhalation risk models. With these methods and more, a Phase 2 Environmental Site Assessment provides reliable conclusions and recommendations for the report users.

Screening Levels

In addition to the use of vapor intrusion risk models and health risk attenuation factors, scientists also compare contaminant detections against government screening levels. In general screening, levels are not legally enforceable standards. Instead, they are considerable guidelines to determine if potential risks exist and whether the encountered contamination may warrant further evaluation. There are numerous environmental screening levels published by various environmental agencies (Local, State, and Federal). The applicability of each publication can vary, depending on the jurisdiction. Moreover, continuous research programs commissioned by environmental agencies advance overtime. Thus, screening levels and their applications do change periodically. 

Phase 2 Environmental Testing Analytical Data

Phase 2 Environmental Testing Analytical Data

Conclusions & Recommendations 

Upon completion of the investigation, all methodologies, findings, and conclusions are reported in a final Phase 2 Environmental Site Assessment Report. Final reports should also include informative data tables and figures that summarize the scope of the assessment. Lastly, per the standard practice of environmental engineering and geology as well as the ASTM and EPA guidelines, recommendations are provided. 

Phase 2 Environmental Site Assessment Shelf Life

Phase 2 reports can become obsolete over time. Especially if a property continues its use of an environmental condition after the date of testing. To illustrate, it’s possible for a gas station storage tank to start leaking years after a Phase 2 Subsurface Investigation. In such a case, that Phase 2 ESA is no longer representative of the gasoline station. Various agencies have different shelf-life policies for Phase 2 ESA reports. Thus, a consultation with a professional geologist or engineer is always a recommendation.

Beware of Low-Price Phase 2 ESAs

Inaccurate and non-representative Phase 2 Environmental Site Assessment results are typically a reflection of a suspiciously low sale price. Recent case studies have shown suspiciously low bidders dropping prices below reasonable rates, solely to win the attention of consumers on a budget. However, unknown to the consumer, the scope of work is also usually reduced below industry standards, in order to maintain a profit. This scenario renders a Phase 2 ESA essentially ineffective. For example, shallower drilling depths, fewer drilling locations, shorter geophysical survey time frames, and less laboratory analysis can make a difference of thousands of dollars. Although consequently, severe contamination and underground anomalies can also be missed due to the omissions.

Quality Assurance 

Equally important to a proper scope of work, is proper quality of work. Usually, a low-cost Phase 2 ESA also reflects on low-quality service. For instance, laboratory equipment method detection limits can be greater than the minimum significant figures of regulatory agency standards. As a result, significant contamination could exist, without any detection by a laboratory’s testing equipment. The result could be faulty conclusions and recommendations and misleading information. 

Cheap Phase II Environmental Quality

Avoid Errors on Phase 2 Reports

Reliance Letters for Phase II Reports

Phase 2 ESA Reliance Letters allow other parties, such as financiers or investment groups, to legally rely upon the technical findings and conclusions of the site assessment report. This must occur during the lifetime of a valid Phase 2 Environmental Site Assessment Report. Typically, this letter is jointly written for a Phase 1 ESA, as well as a Phase 2 ESA. A reliance letter does not serve as an update or modification to the technical report. The costs for an average Phase 2 Subsurface Investigation reliance letter can range between $500 and $800 dollars.

A Phase 2 Environmental Site Assessment can Additionally Include the Analysis of Soil-Gas and Groundwater

Phase 2 Environmental Investigation Drilling

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2 thoughts on “Phase 2 Environmental Site Assessment

  • Allstar

    Our Phase I ESA says a Limited Phase II Environmental Site Assessment. What is meant by “Limited” Phase 2 Subsurface Investigation and does this include all the work on the property for the banks and EPA?

    • Project Geologist II Post author

      All Phase 2 Environmental Site Assessments are “limited subsurface investigations.” The word “limited” applies because a Phase 2 ESA does not actually intend to define the total lateral and vertical extent of contamination (if it exists). To do so, would be far too expensive. Instead, a Phase 2 ESA is an affordable best-practice approach. It’s just to test whether contamination exists or not, in the most-obvious locations. This is why Phase 2 Investigations only cost about $10,000 and up. On the other hand, if one were to request an all-inclusive subsurface investigation, the costs can be $100,000 and up.