Case Study: Resolving Groundwater Contamination in NJ
When Groundwater Contamination Threatens a Deal
Real estate deals can collapse in an instant, and few issues create more panic among buyers, sellers, and lenders than unexpected environmental contamination.
That was the challenge facing a commercial property transaction in northern New Jersey. The deal was moving smoothly until a routine environmental assessment uncovered signs of groundwater contamination. The discovery immediately triggered lender concern, froze financing, and threatened to derail the sale entirely.
For both buyer and seller, this wasn’t just a technical problem; it was a potential deal-breaker. But with Oak Environmental’s expertise and swift action, the contamination was resolved quickly, the property achieved NJDEP closure, and the transaction closed successfully.
This case study highlights how professional environmental investigation and remediation can turn a high-risk situation into a successful outcome.
Background: The Property and the Problem
The subject property was a mid-sized commercial site formerly used for light industrial purposes before being converted into a mixed-use warehouse and office space.
As part of standard pre-sale due diligence, the seller’s attorney commissioned a Phase I Environmental Site Assessment (ESA).
Initial Findings
The Phase I ESA revealed a Recognized Environmental Condition (REC) linked to a historical underground storage tank (UST) used for heating oil.
Historical land-use records also indicated potential solvent handling from prior industrial tenants.
The property appeared clean on the surface, but its environmental past told a different story.
Based on these findings, Oak Environmental was brought in to conduct a Phase II ESA to confirm whether contamination existed.
The Challenge
During the Phase II investigation, groundwater samples collected from newly installed monitoring wells showed petroleum hydrocarbons and volatile organic compounds (VOCs) above the NJDEP Ground Water Quality Standards (GWQS).
The lender placed the deal on hold until contamination was addressed and official regulatory clearance could be obtained.
The Environmental Investigation Process
Step 1: Phase I ESA – Discovering the Risk
The initial Phase I report documented past property use, potential tank locations, and historical industrial operations nearby. The likely cause of contamination was traced to an abandoned UST no longer visible at the surface.
Step 2: Phase II ESA – Confirming the Contamination
Oak Environmental mobilized a field team to perform:
Soil borings and groundwater sampling from multiple points across the property.
Analytical testing for petroleum hydrocarbons, BTEX compounds (benzene, toluene, ethylbenzene, xylene), and chlorinated solvents.
Results:
Contaminant levels exceeded NJDEP standards in two of the groundwater wells, confirming localized petroleum impact — most likely from historical fuel leaks.
Step 3: Source Identification
Historical documentation, including aerial photographs and fire insurance maps, confirmed that a 1,000-gallon heating oil tank had once been installed behind the main building.
This tank, likely decommissioned improperly decades ago, was determined to be the source of the contamination.
The Remediation Strategy
Once the source was identified, Oak Environmental developed a comprehensive remediation plan designed to meet NJDEP requirements and satisfy lender conditions — all while minimizing project downtime.
1. UST Removal and Closure
The first step was safely excavating and removing the underground tank and associated piping. Certified technicians handled disposal according to NJDEP and local health department regulations.
2. Targeted Soil Excavation
Impacted soil surrounding the tank area was excavated and transported off-site to a licensed disposal facility.
Clean backfill was placed and compacted to restore the property for normal use.
3. Groundwater Remediation
Oak Environmental implemented an In-Situ Chemical Oxidation (ISCO) treatment — a process in which oxygen-releasing compounds are injected directly into contaminated groundwater.
This method rapidly breaks down petroleum hydrocarbons without the need for continuous pumping or system installation.
4. Post-Treatment Monitoring
Monitoring wells were used to track chemical reactions and reductions in contaminant concentrations.
Samples were collected at 30-, 60-, and 90-day intervals to evaluate progress.
Results:
Within three months, contaminant levels fell below NJDEP’s Ground Water Quality Standards.
The remediation had successfully neutralized the pollution while keeping disruption to an absolute minimum.
Coordination and Compliance with NJDEP
Throughout the project, Oak Environmental maintained full compliance with NJDEP Technical Requirements for Site Remediation (N.J.A.C. 7:26E).
Regulatory Oversight
A Licensed Subsurface Evaluator (SSE) oversaw all field work and data collection.
All reports were prepared following NJDEP’s required formats, ensuring clarity and traceability.
Documentation
Oak Environmental compiled a complete Remedial Action Report (RAR), including:
Field logs and analytical results.
Waste disposal manifests.
ISCO treatment details.
Case Closure
Following NJDEP review, Oak Environmental issued a Response Action Outcome (RAO) letter certifying that the site met groundwater remediation standards and required no further action.
The RAO satisfied both the lender and the buyer, clearing the way for the sale to close.
The Outcome: A Saved Transaction and a Safer Property
What began as a potential deal-breaker became a success story of precision, speed, and compliance.
Timeline
From Phase I discovery to NJDEP closure: Less than 120 days.
Results
The property sale closed on schedule.
The buyer gained confidence with official NJDEP documentation confirming the site’s safety.
The seller avoided a failed transaction and preserved full market value.
The lender approved financing after receiving environmental clearance.
Added Value
Beyond regulatory compliance, the remediation increased the property’s market appeal. Oak Environmental also provided a maintenance and monitoring plan to prevent future groundwater issues — ensuring continued compliance and peace of mind.
Lessons Learned: What Investors and Owners Should Know
1. Start Due Diligence Early
Early environmental assessments (Phase I ESAs) identify potential problems before closing deadlines — giving time for resolution.
2. Never Ignore Historical Land Use
Old tanks, dry cleaners, or industrial tenants often leave behind hidden contamination. Even if the site appears clean, legacy issues can linger underground.
3. Work with Licensed Professionals
Only NJDEP-certified Subsurface Evaluators (SSEs) or Licensed Site Remediation Professionals (LSRPs) can oversee regulated cleanups and issue valid closure documentation.
4. Keep Records Organized
Maintain copies of all environmental assessments, remediation reports, and NJDEP letters. They’re invaluable during resale, refinancing, or redevelopment.
5. Communication Is Key
Open dialogue between sellers, buyers, attorneys, and environmental consultants ensures that surprises are managed — not magnified.
How Oak Environmental Helps with Groundwater Contamination
At Oak Environmental, we combine technical precision with a deep understanding of New Jersey’s environmental regulations.
Our goal is simple: help property owners, investors, and developers resolve contamination quickly, safely, and fully in compliance with NJDEP standards.
Our Groundwater Services Include
Phase I & II Environmental Site Assessments (ESAs)
Early detection and confirmation of contamination risks.Soil & Groundwater Investigations
Comprehensive sampling, analysis, and interpretation.Remediation Design & Implementation
Cost-effective strategies tailored to site conditions.Regulatory Guidance & NJDEP Coordination
Managing every communication and report from start to finish.Case Closure Documentation (RAO/NFA)
Final certification confirming your site is clean and compliant.
Why Clients Choose Oak Environmental
Proven results across New Jersey’s commercial and industrial properties.
Certified Subsurface Evaluators (SSEs) with decades of field experience.
Fast turnaround times for time-sensitive real estate transactions.
Clear communication that keeps clients and lenders informed every step of the way.
With Oak Environmental, groundwater contamination isn’t a setback, it’s a solvable challenge.
Turning Risk into Resolution
Groundwater contamination is one of the most complex and intimidating issues in real estate. But with the right expertise, it doesn’t have to end a deal.
This case proves that swift investigation, sound remediation strategy, and strict NJDEP compliance can restore both environmental health and transactional confidence.
Whether you’re selling, buying, or developing property in New Jersey, Oak Environmental has the experience and resources to turn environmental challenges into successful outcomes.
Take Action Today
Don’t let environmental risks threaten your property closing. Oak Environmental helps buyers, sellers, and attorneys navigate due diligence with clarity and confidence. Schedule your consultation today at oaknj.com/contact and move your deal forward with compliance and peace of mind.
Oak Environmental — accelerating safe, compliant, and successful closings across New Jersey.
