When purchasing, refinancing, or financing commercial real estate in New Jersey, Pennsylvania, or the greater Philadelphia region, a Phase I Environmental Site Assessment (Phase I ESA) is often a critical part of the due diligence process. But for many buyers and property owners, the process itself remains unclear.
Does someone test the soil? Are samples collected? How far back does the environmental professional investigate the property’s history? And what happens if a potential environmental problem is discovered?
Understanding what happens during a Phase I ESA helps commercial property buyers, lenders, and investors know what to expect — and why the process matters for evaluating environmental risk before closing.
What Is the Purpose of a Phase I ESA?
A Phase I Environmental Site Assessment evaluates a property’s current and historical environmental conditions and identifies potential concerns tied to hazardous substances or petroleum products. Phase I ESAs are generally conducted in accordance with ASTM E1527-21 and can be used to satisfy federal All Appropriate Inquiries (AAI) requirements.
Unlike a Property Condition Assessment (PCA), which evaluates the physical condition of a building and its major systems, a Phase I ESA focuses specifically on environmental risk and potential contamination liability. The investigation covers four major areas: historical and regulatory research, site reconnaissance, interviews and information gathering, and evaluation and reporting.
Step 1: Historical Property Research
One of the most important parts of a Phase I ESA happens before, or alongside, the physical site visit. The environmental professional researches how the property — and the surrounding area — has been used over time, drawing on whatever records are available and applicable: historical aerial photographs, topographic maps, fire insurance maps, city directories, property records, building and development records, and previous environmental reports.
A building that operates as ordinary office space today may previously have housed an automotive repair facility, dry cleaner, manufacturing operation, gas station, or another use associated with environmental concerns. That history often isn’t apparent from a walk-through alone.
Step 2: Environmental Regulatory Database Review
The Phase I ESA also includes a review of applicable environmental regulatory records — for the subject property and, where appropriate, nearby properties — covering things like underground storage tanks, leaking tanks, hazardous material releases, spill incidents, hazardous waste generators, contaminated sites, cleanup sites, and institutional or engineering controls.
This step matters because contamination doesn’t necessarily originate on the property being purchased. A neighboring or historically adjoining property can represent an environmental concern depending on its use, location, and regulatory history.
Step 3: The Site Reconnaissance
The environmental professional then conducts a physical reconnaissance — a visual, non-invasive assessment intended to identify conditions that may indicate environmental concerns. This includes observing current operations, chemical and petroleum storage, drums and containers, aboveground storage tanks, evidence suggesting underground tanks, staining or spills, floor drains, pits and sumps, waste storage areas, unusual odors, distressed vegetation, transformers, and any signs of previous industrial operations. Accessible interiors and exterior areas are typically observed, and adjoining properties are considered from accessible viewpoints.
The goal isn’t simply to determine whether a property looks clean. It’s to identify evidence that may indicate the presence, likely presence, or potential release of hazardous substances or petroleum products.
Step 4: Interviews and the AAI Questionnaire
Environmental due diligence also draws on information from people familiar with the property — current owners, property managers, occupants, facility personnel, buyers, or other individuals with relevant knowledge. For transactions seeking to satisfy federal AAI requirements, the user of the Phase I ESA has specific responsibilities as well, which is one reason completing environmental questionnaires and providing available property information matters.
Information about environmental liens, activity and use limitations, specialized knowledge, purchase-price considerations, and other relevant factors can all contribute to the overall due diligence picture. A Phase I ESA isn’t based solely on what the environmental professional sees during the site visit — it combines physical observations, historical research, regulatory information, and information supplied by knowledgeable parties.
Step 5: Evaluating the Findings
After research, reconnaissance, and interviews are complete, the environmental professional evaluates everything collectively. A central objective is determining whether identified conditions meet the applicable ASTM definitions — including whether a Recognized Environmental Condition (REC) is present. The report may also address other classifications under the ASTM standard, such as historical or controlled recognized environmental conditions.
Not every environmental observation automatically qualifies as a REC. Reaching that conclusion requires weighing the evidence, historical context, regulatory information, and site conditions together.
What Happens If a REC Is Identified?
A REC doesn’t automatically mean a property is contaminated, and it doesn’t automatically mean a transaction should be abandoned — it means a condition has been identified that may warrant further evaluation. Depending on the circumstances, the next step may be a Phase II Environmental Site Assessment, which can include soil testing, groundwater sampling, soil-gas or vapor testing, or other targeted testing, scoped to the concern identified in the Phase I.
The distinction is straightforward: the Phase I identifies environmental risk; a Phase II may physically investigate it.
Does a Phase I ESA Include Soil or Groundwater Testing?
Generally, no — and this is one of the most common misconceptions about the process. A standard Phase I ESA is a research, reconnaissance, interview, and professional evaluation process. It doesn’t ordinarily include soil sampling, groundwater sampling, laboratory testing, or destructive investigation. Those activities are typically associated with a Phase II investigation or another specifically defined environmental scope, which is why a property can go through a Phase I ESA without any drilling, excavation, or sample collection.
How Long Does a Phase I ESA Take?
Timelines vary depending on the property and the availability of information — property size and complexity, historical uses, availability of municipal records, prior environmental documentation, and how responsive owners or property representatives are. Properties with long industrial histories or complicated environmental records typically require more research than newer, lower-risk commercial properties. For buyers working within a due diligence period, ordering the Phase I ESA early can help keep environmental research from becoming a last-minute obstacle to closing.
What Types of Properties Deserve Extra Attention?
Any commercial property can potentially have environmental concerns, but certain historical uses deserve particular scrutiny: gas stations, automotive repair facilities, dry cleaners, manufacturing properties, industrial buildings, machine shops, warehouses involving chemical storage, and properties with known or suspected underground storage tanks.
Current use doesn’t tell the entire story. A retail center that looks environmentally low-risk today may sit on land that supported industrial operations decades earlier — which is exactly why historical research is such a central part of the Phase I process.
Phase I ESA and PCA: Two Different Types of Due Diligence
Commercial property buyers frequently coordinate a Phase I ESA with a Property Condition Assessment because the two reports evaluate fundamentally different categories of risk.
A Phase I ESA asks: what environmental liabilities or contamination risks may be associated with this property? A PCA asks: what is the physical condition of the property, and what repairs or capital expenditures should be anticipated?
A property could have an excellent roof, newer HVAC equipment, and minimal deferred maintenance while still carrying a significant environmental history. Conversely, a property may present little environmental risk while still requiring substantial investment in roofs, pavement, HVAC, or other building systems. Understanding both environmental and physical risk gives investors a more complete picture of the asset before closing.
Why Phase I Environmental Due Diligence Matters in New Jersey and Pennsylvania
Environmental history carries particular weight throughout New Jersey, Pennsylvania, and the greater Philadelphia region, where a substantial inventory of older commercial and industrial properties has passed through multiple changes in use over several decades. Former manufacturing operations, fuel storage, automotive uses, dry-cleaning operations, and other historical activities can leave environmental implications long after the original business has left the property. A modern building appearance doesn’t mean a property has a clean environmental history — that history has to be investigated.
Final Thoughts
A properly performed Phase I ESA is far more than a walk-through of the property. It brings together historical research, regulatory records, site observations, interviews, and professional environmental analysis to help buyers and lenders identify risk before a transaction closes.
The purpose isn’t to prove a property has zero environmental risk — it’s to perform appropriate due diligence, identify conditions of concern, and determine whether additional investigation is warranted. For a commercial property buyer, that information can be invaluable before taking ownership.
Environmental Due Diligence with Core Building Inspections
Core Building Inspections coordinates Phase I Environmental Site Assessments for commercial real estate transactions throughout New Jersey, Pennsylvania, Delaware, and the Philadelphia metropolitan area, alongside Property Condition Assessments and other commercial due diligence services.
Coordinating the Phase I ESA and PCA process helps buyers and lenders evaluate two of the most important areas of commercial property risk: environmental liability and physical building condition.
If you’re purchasing or financing commercial real estate and aren’t sure which due diligence services your transaction requires, contact Core Building Inspections at corecreinspections.com or 609.605.0590 to discuss the property and scope.
