Developers Targeting Land Above Speonk Plume Say They All Intend To Install Vapor Barriers


With a third residential development now being proposed for the west side of North Phillips Avenue in Speonk, this time at 95 North Phillips Avenue, the presence of a roughly two-mile-long plume of contaminated groundwater in the hamlet, first discovered in 2001, is again raising concerns among some community members.

Though they are not legally required to do so by the State Department of Environmental Conservation, or the Suffolk County Health Department, all three developers targeting the hamlet—Georgica Green Ventures in Jericho, CAEC Engineering Design and Construction in Southampton, and Serenity LLC in Manhattan—said they intend to include vapor barriers as part of their respective projects.

While the barriers themselves can vary in design—some are made from rubber and asphalt-coated paper, while others can be constructed from plywood, gypsum board and fiberglass—they are all designed to prevent harmful vapors from entering what is built above them. In these specific instances, the barriers would be installed to prevent vapors from volatile organic compounds, or VOCs, from escaping the contaminated groundwater that lies under them and entering either new apartments or new houses.

According to Denise McCauley, a business developer with CAEC Engineering Design and Construction, the 44 apartments that his company wants to construct in 11 buildings at 85 North Phillips Avenue would include vapor barriers under their foundations. With that project, the barrier would be what’s called a “rat slab,” a thin layer of concrete poured over the unit’s crawlspace. The barrier, according to Ms. McCauley, would prevent vapors from entering the apartments if they are eventually built.

Georgica Green Ventures President David Gallo also confirmed that his company intends to install vapor barriers—he could not confirm the type when reached this week—if Southampton Town ultimately signs off on his plan to built 50 workforce housing apartments on 4.4 acres located at 41 North Phillips Avenue, commonly referred to as The Castle property.

Meanwhile, Barry M. Bernstein, the owner of the property at 95 North Phillips Avenue, which is also situated above the plume, is still advancing plans to build 13 luxury homes on the 15 acres he owns along the west side of the road. Those plans, which he says were approved by Southampton Town this summer, also call for the installation of vapor barriers.

“We plan to use a sub-slab depressurization system,” Mr. Bernstein wrote in an email on Tuesday. “The concrete slabs that come into contact with the ground will be laid over a gas-permeable material. Plastic sheets or vapor barriers will be provided.”

He added that ground could be broken on his subdivision within the next six months.

In addition to the vapor barriers, Mr. Bernstein said his homes will be connected to public water, noting that private wells would never be considered due to the plume.

Bob Mozer, a professional hydrogeologist who lives in Remsenburg, has been periodically posting his thoughts about the proposed developments and their proximity to the plume that, the DEC previously noted, primarily contains perchloroethylene, trichloroethene, trichloroethane, carbon tetrachloride and chloroform.

Describing himself in a Facebook post “as a veteran hydrogeologist who has conducted Hazardous Waste Remedial Investigations at numerous state and federal Superfund sites and who has had to deal with these types of issues,” Mr. Mozer noted that, presently, there is no data that “supports a conclusion that building a structure on land that is situated above the area of groundwater contamination caused by the illegal disposal of volatile organic compounds (VOCs) in our community will be impacted by soil vapor intrusion into that structure.

“Nevertheless,” he continued, “while that data may surface in the future, in the meantime, it would be prudent for us to request that any developer completing a project over the plume install a vapor barrier under the building footprint to prevent the possible intrusion of VOCs into an occupied space.”

Mr. Mozer posted his comments on the “Speonk Remsenburg Eastport Westhampton Westhampton Beach Neighbors” Facebook page. In the same posting, he notes that neither the DEC, nor the Suffolk County Health Department, currently requires vapor barriers in such instances. He also encourages residents to contact both departments if they are concerned about the proposed projects.

Robert D. DeCandia Jr., who works for the DEC and is listed as the main point of contact for project-related questions regarding the Speonk Solvent Plume, referred all questions about the contamination to the agency’s public information office. Bill Fonda, a spokesman for the DEC, said he would have to ask the agency’s experts if it is safe to build on top of a known plume.

Engineers with Patchogue-based Environmental Assessment and Remediations are continuing to take and collect groundwater samples from the plume every 15 months, all part of ongoing monitoring of the contamination ordered by the DEC. The results of samples collected this past fall are still pending, according to Mr. Mozer. The first set of samples, retrieved in 2014, indicated the presence of 16 VOCs, eight of which had concentrations exceeding the DEC’s acceptable limits for those compounds, according to the report filed by the Patchogue firm.

According to a plume fact sheet released by the DEC in February 2013, it was determined that no actions were needed to address exposures related to soil vapor intrusion, described as “the process by which vapors volatilize, from volatile organic compounds in soils and/or groundwater, and then move into the indoor air of a structure through cracks or holes in a foundation.”

The plume, which begins about one mile north of the intersection of Old Country Road and North Phillips Avenue and has traveled more than 2,000 feet south of Montauk Highway, was discovered in 2001 after an unidentified resident complained that the well water in Speonk tasted odd. The pollution—the source of which has not been determined and might never be—was the subject of a massive 16,000-page characterization study commissioned by the DEC and conducted by the Massachusetts-based environmental consulting firm Camp Dresser and McKee.

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