DIAMOND ALKALI CO.
NEWARK, NJ
Cleanup Activities
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Background
The Diamond Alkali Superfund site includes the former manufacturing facility at 80-120 Lister Avenue in Newark, New Jersey, the Lower Passaic River Study Area (LPRSA), and the Newark Bay Study Area. The LPRSA includes the 17-mile tidal stretch of the river from Dundee Dam to Newark Bay and tributaries. The Newark Bay Study Area includes Newark Bay and portions of the Hackensack River, Arthur Kill and Kill van Kull. The area surrounding the site is densely populated and heavily industrialized.
Kolker Chemical Works, Inc. produced Dichloro-diphenyl-trichloroethane (DDT) and other chemicals at 80 Lister Avenue in the 1940s. The Diamond Alkali Company (later purchased by and merged into Occidental Chemical Corporation or OCC) owned and operated the facility in the 1950s and 1960s. The facility manufactured agricultural chemicals including herbicides used in "Agent Orange", a defoliant chemical that removes leaves from trees and plants. These manufacturing processes produced an extremely toxic chemical, 2,3,7,8-TCDD (dioxin).
The state of New Jersey and EPA sampled at and near 80 Lister Avenue and in the river in 1983. Sampling revealed high levels of dioxin. Following the sampling, EPA listed the site on the Superfund National Priorities List (NPL) in 1984. EPA and NJ found dioxin, pesticides, and other hazardous substances in the soil and groundwater at 80-120 Lister Avenue as well as dioxin, polychlorinated biphenyls (PCBs), metals, polycyclic aromatic hydrocarbons (PAHs), and pesticides in sediment in the Lower Passaic River.
New Jersey prohibits consuming fish or shellfish from the Lower Passaic River and Newark Bay. Cleanup activities to date include immediate actions at 80-120 Lister Avenue and surrounding properties, removal actions in the Lower Passaic River, and the interim cleanup for 80-120 Lister Avenue. EPA selected a cleanup plan in March 2016 for the lower 8.3 miles of the Lower Passaic River.
EPA selected a cleanup plan in September 2021 to address an interim cleanup action for the upper 9 miles of the Lower Passaic River. Additional investigations and planning for long-term cleanup are ongoing.
The EPA released a Record of Decision for a final cleanup plan at 80 and 120 Lister on January 17 2025. The EPA's preferred alternative "Optimize Containment Remedy" aims to finalize cleanup efforts by improving existing systems and ensuring long-term safety and containment at the Diamond Alkali Superfund site.
What Has Been Done to Clean Up the Site?
EPA and the New Jersey Department of Environmental Protection (NJDEP) found high levels of dioxin at and in the vicinity of 80-120 Lister Avenue and in the Passaic River in 1983. Based on these investigations, EPA and NJDEP secured the properties at 80-120 Lister Avenue, covered the exposed soil to prevent the spread of contaminants, and cleaned up dioxin found on nearby properties. EPA listed the site on the National Priorities List in 1984.
Based on additional studies of the contamination on 80-120 Lister Avenue, EPA selected an interim containment cleanup plan in 1987, which was completed by Occidental Chemical Corporation (OCC) under EPA oversight in 2001. The interim cleanup included covering contaminated material with a cap to prevent it from spreading, installing subsurface slurry walls and a flood wall around the property to block the spread of contaminated groundwater, and constructing a groundwater collection and treatment system.
EPA, NJDEP and a number of other federal and state agencies investigated the contamination in the Passaic River in the 1980s and 1990s. In the early 2000s, EPA expanded the study to address the 17-mile Lower Passaic River, and in May 2007, EPA signed an agreement with a group of potentially responsible parties known as the Cooperating Parties Group (CPG) to complete the 17-mile study, under EPA oversight.
During the 17-mile study, the sediment of the lower 8.3 miles of the Lower Passaic River were found to be a major source of contamination to the rest of the river and Newark Bay, leading EPA to select a cleanup plan for that lower 8.3-mile stretch in 2016. OCC under EPA oversight designed the lower 8.3-mile cleanup. The final design was approved by EPA in May 2024.
In 2012, Tierra Solutions, on behalf of OCC and under EPA oversight, dredged sediment with very high levels of dioxin contamination from the Lower Passaic River adjacent to 80-120 Lister Avenue. In 2014, the CPG, under EPA oversight, dredged and capped a highly contaminated mudflat at river mile 10.9 on the east bank of the river, near a park in Lyndhurst, NJ.
In 2004, EPA and OCC signed an agreement in which OCC agreed to conduct a study of the Newark Bay Study Area (Newark Bay and portions of the Hackensack River, Arthur Kill and Kill van Kull) under EPA oversight. That study is on-going.
In September 2021, EPA selected an interim plan for the upper nine miles of the LPRSA that calls for cleaning up sediment and erosional areas by dredging and capping areas of the riverbed between river mile 8.3 and Dundee Dam. OCC under EPA oversight is currently designing the interim upper nine mile cleanup. After the interim cleanup plan has been completed, EPA will use an adaptive management approach to sample and gauge the progress towards meeting the preliminary cleanup goals that will be established and documented in a final Record of Decision.
EPA evaluates the protectiveness of cleanups every five years in a process called a Five-Year Review. EPA completed the fifth Five-Year Review in 2021 for the 80-120 Lister Avenue properties.
What Is the Current Site Status?
EPA divided the Diamond Alkali site cleanup into four phases, called Operable Units (OUs): the 80-120 Lister Avenue properties (OU1), the lower 8.3 miles of the Lower Passaic River (OU2), the entire 17-mile Lower Passaic River Study Area (LPRSA) (OU4), and the Newark Bay Study Area (OU3).
Operable Unit 1 (80-120 Lister Ave): The EPA issued a Record of Decision for a final cleanup for 80 and 120 Lister Avenue. The plan addresses contaminated soil, debris and groundwater at the site and outlines the EPA's preferred cleanup alternative, as well as other alternatives considered.
The EPA’s selected cleanup alternatice is “Alternative 2”, which is an optimized containment remedy. This would enhance the existing interim solution with improvements like replacing groundwater extraction wells, upgrading the groundwater treatment system, and maintaining the site's cap in perpetuity, which means forever. The EPA considered several alternatives ranging from no further action to targeted excavation with off-site disposal. However, excavation is challenging due to the site's complex structure and hazardous contamination beneath critical infrastructure like the floodwall. The EPA evaluated the proposed alternatives based on their protectiveness of people's health and the environment, compliance with regulations, long-term effectiveness, and cost.
The EPA's plan aims to finalize cleanup efforts by improving existing systems and ensuring long-term safety and containment at the 80-120 Lister Ave portion of the Diamond Alkali Superfund site while minimizing short-term risks associated with excavation. Public comment is encouraged during the comment period, community feedback will be considered in the final decision-making process. The EPA, in consultation with the NJDEP, will finalize the cleanup plan after considering all public comments and additional data.
Operable Unit 2 (Lower 8.3 miles of the Lower Passaic River): EPA selected a cleanup plan for this stretch of the river in 2016. The cleanup includes some dredging and placing a cap over the bottom of the river, bank-to-bank, to isolate the contaminated sediment from the rest of the river system. Under the design of the cleanup plan, approximately 2.5 million cubic yards of sediment will be dredged from the river before the cap is installed, so that the cap does not make flooding worse and to accommodate the federally-authorized navigation channel in the 1.7 miles of the river closest to Newark Bay. The dredged materials will be barged or pumped to an upland processing facility, where it will be squeezed dry and sent off-site for disposal at licensed disposal facilities.
Occidental Chemical Corporation performed the engineering work needed to design this complex work in the lower 8.3 miles, under EPA oversight. EPA approved the design in May 2024. For the next step, EPA expects that performing parties will build the upland processing facility, after which it will take approximately eight years to dredge and cap the river. EPA expects the cleanup to be performed and funded by potentially responsible parties.
Operable Unit 4 (17-mile Lower Passaic River Study Area [LPRSA]): In September 2021, EPA selected an interim cleanup plan for the upper 9 miles of the Lower Passaic River that calls for addressing specific areas of sediment that serve as sources of contamination to the rest of the river and to the food chain. The OU4 cleanup is intended to complement the OU2 cleanup plan, the two working together to address the human health and ecological risk posed by the site-related contamination in the Lower Passaic River. EPA included in the cleanup plan dredging and capping areas of the riverbed as well as areas at depth that may become exposed through erosion. The dredged materials will be processed at one or more commercial processing facilities for off-site disposal at licensed disposal facilities. OCC under EPA oversight is currently designing the upper nine mile cleanup. The design and construction phases are each expected to take about 3 - 4 years to complete.
After the interim cleanup has been completed, EPA will sample and measure progress toward meeting the cleanup goals that are still being developed, in consultation with the New Jersey Department of Environmental Protection (NJDEP). EPA will decide if any further work is needed, and document a final cleanup plan in a Record of Decision.
Operable Unit 3 (Newark Bay Study Area): Occidental Chemical Corporation, under EPA oversight, is currently doing a comprehensive study called a remedial investigation and feasibility study (RI/FS) to examine the nature and extent of contamination and options for addressing it. EPA approved the report that lays out the results of the investigation in May 2022 and anticipates that the feasibility study will be submitted for EPA review in 2025. EPA expects to use this information to propose a cleanup plan for Newark Bay in 2026.
Once these various river and bay cleanups have been completed, it will still be many years before the levels of contamination in fish and crab have decreased to levels that are considered safe to eat.