DIAMOND HEAD OIL REFINERY DIV.

As of May 2026, the Diamond Head Oil Refinery Superfund site is considered “Insufficient Data to make a Human Exposure evaluation” (HEID). This status does not necessarily mean that unacceptable exposures are occurring. The site is fenced and inactive. Contaminants identified in site soils and sediments include chromium, lead, dioxin, polychlorinated biphenyls (PCBs, including Aroclor mixtures), thallium, benzo[a]pyrene, and aldrin. A historic “oil lake” was present over portions of the site, and remnants were evident in soil and sediment samples. EPA selected an early action remedy in 2009 to address oil‑lake remnants, but a bench‑scale study indicated the approach would not be effective. In 2017, EPA amended the remedy to address the oil‑lake remnants and issued a Record of Decision (ROD) to address contaminated soil and sediment across the remainder of the site. Construction of the remedy to address the oil‑lake as well as the soil and sedimet has been completed. Additional information is still needed to determine whether actual or reasonably anticipated human exposures are occurring above acceptable risk‑based levels for groundwater, which is being addressed under a separate operable unit (OU).

Planned activities to collect sufficient information include completing the groundwater operable unit Remedial Investigation/Feasibility Study (RI/FS); installing and sampling additional monitoring wells to delineate plume extent, trends, and migration; conducting any needed surface water/sediment screening where groundwater discharge is suspected; and preparing a Human Health Risk Assessment (HHRA) that evaluates relevant exposure pathways. EPA will use the RI/FS and HHRA results to support a Human Exposure determination and to inform the groundwater remedy decision.

EPA currently anticipates there will be sufficient data to make a Human Exposure determination by September 2033 because the groundwater OU RI/FS and HHRA are expected to be completed and EPA expects to issue a groundwater ROD by that time.

If you live or work near the site, you can reduce your potential exposure by not trespassing on fenced areas, avoiding contact with on‑site soils and nearby drainage sediments, and using municipal water where available or testing private wells before use. Follow any posted warnings or local advisories and allow access for sampling if requested. For more information, contact the EPA Community Involvement Coordinator Drew Curtis through the site webpage or at (212) 637-3726 or [email protected]. EPA will continue to meet with residents and stakeholders, issue public notices and updated fact sheets, and keep the site profile on EPA’s website up to date.