Public Oversight Needed in Clean-up of Toxic Chemicals at Former Hercules Plant in Kenvil

by Brian T. Lynch, MSW

The clean-up of the 1,000-acre Hercules tract in Kenvil has always been a private enterprise with insufficient public oversight. That needs to change before March 1st, when the Roxbury Planning Board and the public will hear the case for approving a Hartz Mountain Corporation plan to build 57 acres of warehouses on this polluted land.

When 150 years of manufacturing explosives ended in 1996, it left behind perhaps the most toxic and complex land contaminations in the state of New Jersey. The list of toxins on the Hercules tract is long and varied. It includes explosives such as TNT, ammonium nitrate, and RDX; PCBs, arsenic, lead, chromium, and a host of volatile organic compounds.

A portion of the Hercules tract is the area to the right of the highway (Rt. 46) in this ariel photograph.

The massive site pollution created a major quandary for the New Jersey Department of Environmental Protection (DEP) and potentially a huge financial burden for taxpayers if the property were designated as a Superfund Site. That didn’t happen. Instead, under what was a new state law at the time, an agreement was reached with Hercules and later with the current owners, Ashland Global (an international chemical company), to privately conduct and pay for the analysis and site remediation at the Hercules plant.

Documentation: That private effort has been underway now for almost 3 decades. A trove of documents on the progress has been submitted to the DEP over the years. The information is public but not conveniently accessible. The work included a twenty-year-long, two-phase scientific study of the property. A final report summarizing the findings was completed six years ago and submitted to the DEP. It is called the Phase II Remedial Investigation Report (RIR). The report documents the extent of chemical contaminants in the soil, sediments, groundwater, and surface water on the property.

That 1,800-page RIR and tens of thousands of other Hercules documents were recently obtained by the Raritan Headwaters Association* under an OPRA request to the DEP. A review of these documents is underway, but potential environmental risks are already apparent. Here are samples of information contained in the RIR Summary. From the Report regarding the surface waters and sediments at the facility:

• Arsenic, cadmium, chromium, cobalt, copper, lead, mercury, nickel, vanadium, and zinc were detected in surface water and sediment.

• SVOCs were detected in sediment, but not in surface water at five of the seven co-located sample points.

• Beryllium, selenium, and silver were detected in sediment and not in surface water, indicating these constituents are not partitioning [moving] from sediment to surface water.

• Aluminum, barium, calcium, iron, magnesium, potassium, and manganese were detected in both surface water and sediment samples from each co-location. Per the United States Geological Survey (1984), these metals are commonly found in surficial geologic material in the vicinity of the Facility.

And this:

In certain instances, constituents were present at concentrations that exceeded their aqueous solubility limits by two to four orders of magnitude, indicating that these constituents were associated with suspended sediment entrained in the surface water.

Here is another example of what the report says regarding soil in another area of the property:
From the Report:

TNT in soil exceeds its IGWSSL [Impact to Groundwater Soil Screening Levels] in the TNT Area, the PETN [Pentaerythritol Tetranitrate] Area, and the western portion of the Dynamite Area. TNT and related breakdown constituents (4-Amino-2,6-dinitrotoluene, 2,4/2,6-Dinitrotoluene, and 2-Amino-4,6-Dinitrotoluene) exceed their respective GWQS[Groundwater Quality Standards] in… [12]… monitoring wells… located downgradient of soil sample results exceeding the IGWSSL for TNT.

And this example is regarding groundwater under the property: 

RDX [1,3,5-Trinitroperhydro-1,3,5-triazine, Hexahydro-1,3,5-Trinitro-1,3,5-Triazine] exceeds its GWQS in a monitoring well (MW-36) co-located with and/or downgradient of soil samples with RDX detections that exceed its IGWSSL.

Decommissioning of the site: A massive amount of demolition and decontamination work initially occurred in the early 2000s. Many buildings and other structures were demolished and disposed of. Miles of pipelines were drained of toxic chemicals and removed from the ground where they were buried, and the decades-long study of the site was begun.

Stability and Risk Factors: In the intervening years since the initial decommissioning work, the land has been largely undisturbed. The Remedial Investigation Report (RIR) summary found that the current hydrology, the regrowth of vegetative cover, and an absence of human activity have stabilized the many chemical and metal contaminants on the Hercules property, with the exception of contaminants that may be migrating offsite through groundwater and streams. This still leaves pockets of substances in highly toxic quantities scattered throughout the site. As a result, the Hercules property remains off-limits to the general public.

From the Report:

“Facility-related influences in environmental media result in unacceptable levels of [the] potential risk to ecological receptors based on the screening and conservative exposure modeling conducted in the EE/ERA… Current Facility use precludes human health exposure risks, as personnel permitted to access the Facility are trained in the identification and control/mitigation of potential exposures.”

When current stabilizing conditions on the Hercules property change, the contaminants, or "constituents of concern" (COC) as referenced in the report, could migrate off-site and result in significant health risks for Roxbury residents and anyone else downstream from the Black River. Many people are unaware that the Black River originates from the southern wetlands and prolific freshwater springs on the Hercules property; this is the headwaters of the Black River. The river emerges from its source, known as the Great Spring, as a fully formed stream with a volume of water that exceeds the rainfall total on the property. The river flows from the southern wetlands on the Hercules site into Sunset Lake on the border with Mine Hill, then into the Black River Pond. The Black River is also known as the Lamington River, a major tributary of the North Branch of the Raritan River. The river is part of the drinking water supply for 1.8 million residents in New Jersey.

Pollution Hot Spots: The entire Hercules site is cross-contaminated due to historical factors such as massive explosions, construction activity, chemical spills, and prior waste disposal practices. Still, concentrations of chemical pollutants in excess of present safety standards are mostly found in locations where those substances were stored or used in manufacturing. For example, in the section referred to as the Maintenance Area near the center of the property, there was once an electrical generation plant where Hercules made its own electricity. It contained many electrical components that used PCB as a coolant. The huge 1940 explosion destroyed this equipment spreading PCBs over the property, much of which seeped into the soil at that location. In the area where TNT and dynamite were made, spills, past explosions, and antiquated production practices left unsafe concentrations of toxic explosives and energetic chemicals (or E&E) in the soil.

Near Duck Pond to the north, chemical waste, and other polluted items were burned in a burn pit that released toxic chemicals into the air and surrounding soil. Further west of the burn pit, there is a licensed landfill covering multiple acres. According to documents recently reviewed, there is no record of what was deposited in that landfill in the early years of its operation. In another area, there is significant lead contamination in the soil where Hercules fabricated equipment made of lead (because it doesn’t spark when struck). There is also an inactive chemical waste treatment plant that is still licensed by the DEP to release up to 135,000 gallons of treated wastewater into the Black River daily. No wastewater has been released since 2002, and the license is up for renewal. An application to renew that license was just submitted to the DEP this month. The Raritan Headwaters Association has submitted a public comment on the proposed renewal asking for a public hearing before the approval.

The Maintenance area mentioned above is where tons of PCB-tainted soil was hauled away last spring to special landfills. The TNT and Dynamite Areas are the current focus of bioremediation activities. These remediation activities and future redevelopment require disturbing the soil and vegetation that keep toxic chemicals from migrating off the property. That’s why precautions being taken to prevent this from happening are essential to protect the environment and maintain human safety. The public has a right to know how we are being protected.

Redevelopment and Remediation Impacts: Hartz Mountain Corporation is proposing to build 57.4 acres of warehouses in the central and north-central areas of the property.  The redevelopment plan would encompass about 200 acres of the Hercules site, much of which would be covered by water-impervious surfaces (roofs, sidewalks, parking lots, roadways, etc.).

Covering such a large area of Hercules with impervious surfaces is a feature of the remediation plan. The purpose is to cap tainted soil to prevent it from migrating off-site. The redevelopment area will generate over one-hundred-million gallons of stormwater per year, based on rainfall averages. The plan calls for this rainwater to be captured, treated, and released to the Black River. Rainwater that falls on hot rooftops and blacktop is much warmer than water that falls on shaded soil. Warm water holds less oxygen and can threaten the survival of fish and other aquatic species that require cooler temperatures. Stormwater retention basins and spillways also alter the hydrology of the land and can potentially release contaminates trapped in the soil or sediments on the property into the groundwater or surface water.

The soil bioremediation project focuses on the presence of explosive and energetic chemicals concentrated in the soil in the areas where TNT and Dynamite were manufactured. The process requires exposing the soil by removing trees and overgrowth. The soil is then scraped up and ground up in a milling process to reduce the larger crystals of chemicals in the soil. Next, water and commercial bioactive agents are added to the soil to initiate a composting-like process designed to break down the contaminants into safer chemicals. The treated soil is stored in pods within the Black River wetlands buffer zone.

Public Oversight Needed: Critically, bioremediation and redevelopment activities require disturbing the soil and vegetation that keep toxic chemicals from migrating off the property. That is why taking precautions is so essential. The public has a right to know about, and comment on, the steps to keep them safe during the site remediation and redevelopment. The public has a right to know about, and comment on, potential impacts that future development may have on natural features on the property (springs, wetlands, aquifers, forests, and wildlife), local drinking water supplies from public and private wells, and the Black River’s downstream communities in Roxbury and beyond. Raritan Headwaters Association will be taking steps to have the NJDEP provide more information and hold more public hearings for local residents. 

The Roxbury Planning Board will begin the public review of Hartz Mountain’s site development plan on March 1, 2023, at 7:30pm at the Roxbury Township Town Hall, 1715 Route 46, Ledgewood. The meeting is open to the public.

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* Raritan Headwaters Association is the watershed association that protects Watershed Management Area 8. With programs in science, advocacy, education, land preservation, and stewardship, it serves as the watchdog for the 470-square-mile North and South Branch Raritan watershed, a region covering 38 municipalities in New Jersey’s Hunterdon, Somerset, and Morris counties.