The Diamond Alkali Co. site covers a former manufacturing facility at 80-120 Lister Avenue in Newark, New Jersey, the 17-mile Lower Passaic River, and Newark Bay. The facility produced agricultural chemicals, including components of Agent Orange, from the 1940s through the 1960s. That process generated dioxin as a byproduct. EPA and New Jersey sampling in 1983 found high levels of dioxin in soil, groundwater, and river sediment, and the site was added to the Superfund National Priorities List in 1984.
More than 50 chemical substances have been identified as contaminants at the site. Groundwater and soil at the Lister Avenue facility contain chlorinated organic compounds, heavy metals such as lead and mercury, pesticide residues including DDT, and compounds like benzene and vinyl chloride. The Passaic River sediment contains 2,3,7,8-TCDD, a highly toxic dioxin, along with PCBs, DDT breakdown products, dieldrin, and metals including copper, lead, and mercury.
Cleanup is organized into four operable units. In January 2025, EPA issued a final cleanup plan for the Lister Avenue property focused on upgraded groundwater treatment and permanent soil capping. For the lower 8.3 miles of the Passaic River, EPA approved the cleanup design in May 2024, calling for dredging about 2.5 million cubic yards of sediment and capping the riverbed, with work expected to take roughly eight years. For the upper nine miles of the river, Occidental Chemical Corporation is currently designing an interim cleanup plan selected in September 2021. A comprehensive study of Newark Bay is underway, with a cleanup plan expected around 2026. Construction has not yet been completed at the site overall.
Human exposure at the site is classified as not under control. People continue to catch and eat contaminated fish and shellfish from the Lower Passaic River and Newark Bay. New Jersey prohibits consuming any fish or crab from the Lower Passaic River, and blue crab fishing is completely prohibited. Mercury, PCBs, and dioxins are the primary contaminants found in fish and shellfish. These chemicals pose particular risks to pregnant women, women considering pregnancy, nursing mothers, and children.
Community members can stay involved through the Passaic River Community Advisory Group, which holds regular meetings, with sessions scheduled for July 20 and October 19, 2026. EPA provides update fact sheets in English, Spanish, Chinese, Polish, and Brazilian Portuguese. Federal Natural Resource Trustees, the National Oceanic and Atmospheric Administration, and the U.S. Department of the Interior have also opened a portal for community ideas on Passaic River restoration projects. The EPA Community Involvement Coordinator for the site is Drew Curtis, reachable by phone or email.
