WILMINGTON — Since the EPA recently finalized their proposed remediation plan for the Olin Chemical Superfund Site, two representatives from the town’s environmental consultant, GeoInsight, gave an overview of the plan at the Board of Selectmen meeting on Monday night. To start, Chairman Jonathan Eaton reminded the board that the site located at 51 Eames St. ceased operation in the 1980s.
The main GeoInsight representative explained the EPA issued a finalized plan for two areas (soil and sediment, and surface water) and an interim plan for the third area (dapple brine and groundwater). The plan costing Olin $48 million includes the demolition of one entire plant, the installation of a new remedial system to extract petroleum from the surface of the water, the installation of a new treatment system to treat the extracted groundwater, and the removal of contaminated soil and sediments.
Some areas will receive protective capping. The EPA will work with and carefully monitor the existing slurry wall.
The interim plan involves extracting dapple brine and contaminated groundwater. There is currently an ongoing investigation that will help determine the updated timeline and finalized plan for this area of the site.
“Olin is looking for potential data gaps to see the extent of the contamination and the impact,” the GeoInsight rep explained.
The other GeoInsight representative, Robert Reynolds, shared that this part of the process is expected to last about a decade with 2-3 years to get started. The first rep answered a question from the board to say that the new groundwater treatment system will be necessary through the end of the groundwater treatment.
Board member Kevin Caira next asked how much extrapolated minerals would be transported offsite, and was told that the largest removal is the 4,000 cubic yards of contaminated soil. He also brought up the aforementioned slurry wall.
The GeoInsight representative shared Caira’s concerns about said slurry wall, where the plan includes closing the window for groundwater equalization.
“We’re going to be looking closely at the integrity of the slurry wall and the monitoring that’s needed to make sure it’s operating effectively,” he said.
However, he claimed that the wall isn’t damaged, while Town Manager Jeff Hull remembered the wall has been up for more than 25 years.
Eaton cited a concern that perhaps the EPA had simply chosen the least expensive option for removing the least amount of soil and sediment as possible.
The GeoInsight representative responded, “The one picked is the least expensive besides no action.”
He later said GeoInsight’s position is that the approaches highlighted by the EPA strike a fair balance between the risks of the remedial work and a better outcome for the site.
Another of the board’s concerns was that the EPA would only be targeting areas that have at least 5,000 nanograms of MDMA per liter.
“The threshold is over 4,900 nanograms per liter higher than what everybody agrees is too dangerous to drink,” Eaton said.
Caira stated this was unacceptable and wanted to consider what steps may be taken to get the EPA to reconsider these levels. Reynolds answered they’re concentrating first on the areas of mass contamination but hope to figure out other ways to extend the area of extraction or decrease the MDMA levels.
The board could also make their opinions known at upcoming meetings with the EPA regarding this site, GeoInsight reminded them.
Special Town Counsel Dan Deutsch chimed in at the end to assure everyone that the solution isn’t perfect, but it depends on the information that comes up as the cleanup begins.
He said, “I share the concerns of the town regarding the scope of the draft interim and final remedial action plans and the reasons for adopting certain parameters.”
Hull also shared that he’s been working with other town staff on a document with questions and comments to submit to the EPA prior to the meeting on Aug 25.
While the state delegation were in attendance on the meeting for a different item, Senator Bruce Tarr, Representative Ken Gordon, and Representative David Robertson all said later in the call they appreciated hearing this update and look forward to working towards remediation.
The board didn’t vote on this item, but Eaton shared dates for a public informational meeting and Q&A on Aug. 25 and an upcoming formal public meeting with the EPA on Sept. 22. More information can be found at epa.gov/superfund/olin.