Hercules in Brunswick

Brunswick FACILITY

Since ceasing active manufacturing in 2023, the Brunswick facility has undergone a massive transformation. Stump piles are gone, water towers are down, and buildings are razed. Meanwhile, remediation of soil at ground level and groundwater below the ground continues.

EPD re-issued the hazardous waste permit for the Brunswick facility in December 2022. Despite its name, the new “hazardous waste permit” reflects the fact that neither Hercules nor Pinova is storing hazardous waste at the Brunswick facility as was done in the past. The permit includes an adaptive Corrective Action Plan (“CAP”) for comprehensive remediation of the Brunswick facility that took into account feedback received during 2021’s public review process.

The CAP outlined five pillars of environmental remediation to be accomplished by Hercules, including addressing soil impacts near a former tank farm, sitewide soils across the former facility, shallow groundwater, deep groundwater, and potential vapor intrusion at certain former facility buildings. The work called for by the CAP in all five areas has since been completed. Due to the success of the deep groundwater remediation, Hercules voluntarily expanded remediation of deep groundwater and conducted field testing of an additional groundwater remedy, amid the active closure and demolition of the plant. Shallow groundwater remediation efforts yielded modest improvements, and further work is under way to enhance performance.

Following the unexpected closure of the plant, Hercules and Pinova are now working to continue remediation with an eye toward future sale and redevelopment of the former plant property.

What’s been done and what’s next

Since the 1980s, Hercules has remediated more than 50,000 tons of potentially contaminated soil at the Brunswick facility and actively remediated groundwater sources on-site and at its boundaries. In 2021, Hercules remediated soil in several areas and installed vapor intrusion mitigation systems at various buildings on-site. In 2022, Hercules obtained EPD’s approval of its CAP. From 2022 through 2024, Hercules implemented key aspects of the CAP, including three groundwater remediation plans, completed removal of contaminated soils from various locations across the facility, and completed remediation of a former tank farm area.

Soils

The CAP explains how Hercules will identify additional areas of soils to be remediated and the technologies that will be available to be deployed as necessary. In 2023, Hercules implemented a plan to excavate and remove additional soils throughout the site. Additional targeted soil removal work occurred in 2025 at the Marsh Yard property east of Highway 17 and adjacent to Dupree Creek.

Groundwater

Hercules investigates and monitors groundwater at the Brunswick facility and off-site areas through a monitoring well network consisting of more than 100 monitoring wells. The impacts caused by historical activities at the Brunswick facility are generally limited to the upper surficial aquifer — roughly the first 100 feet below the ground surface. This impacted groundwater does not pose a risk to human health because no one in the area drinks water sourced from the surficial aquifer. With the ocean and tidal creeks so near the Brunswick facility, water in the eastern portions of the Brunswick facility surficial aquifer is brackish and would have an unpleasant taste. People in the area rely on water from the Upper Floridan aquifer, which lies hundreds of feet below the impacted groundwater zone. In 2022, Hercules confirmed that the few private water supply wells located on Terry Creek Road (east of the facility) withdraw water from the Floridan aquifer, which is not affected by the facility. However, two of these wells were replaced with deeper wells as a conservative measure of protection.

Thick layers of clay, called “confining units,” separate the various aquifers and prevent contamination near the surface from reaching deeper aquifers. The Upper Floridan aquifer is at least 500 feet below the ground surface.

Though there is no exposure to the contaminated groundwater in the area of the former Brunswick facility, Hercules has nevertheless implemented three different EPD-approved groundwater treatment plans since 2021. The plans address on-site and off-site groundwater to the east of the facility. The groundwater treatment plans targeting groundwater 70-100 feet below the ground surface at the eastern portions of the facility have been particularly effective, reducing concentrations of targeted contaminants by more than 90%.

As a result of this success, in 2024, Hercules expanded one of the treatment systems to address a broader area in the eastern portion of the facility.

Going forward, Hercules will continue its on- and off-site monitoring of groundwater in the upper surficial aquifer to confirm the effectiveness of these remedies and to understand any potential changes in conditions.

Vapor Intrusion

In the last few years, while the facility was still operating, Hercules performed a comprehensive assessment of possible vapor intrusion at all buildings at the Brunswick facility. Hercules worked with EPD to evaluate and make adjustments to any buildings where vapor intrusion posed a potential concern. Hercules completed this work in 2022. However, all of these vapor mitigation systems were removed during the demolition of the facility. As a precautionary measure, any future buildings will have vapor barrier systems built as part of their construction.

Hercules recorded environmental covenants for the plant properties that require any necessary controls for vapor intrusion to be incorporated into any future development to eliminate potential exposures.

All of Hercules’ work was performed in accordance with technical guidelines issued by EPA and EPD and under the oversight of EPD and EPA, as applicable.