State environmental officials have changed the classification of a 2-mile-long underground plume of pollution in the Speonk-Remsenburg area to a category that calls for continued monitoring, but involves no effort to clean up the contamination.
The site, called the Speonk Plume, has been studied by state and county officials for a decade, but officials told an audience of more than 100 residents Wednesday night that the original source of the contamination was never identified, despite an estimated $1.5 million spent by the state. County and federal officials have funded similar research.
Not knowing the source creates a problem with getting funds for some cleanup programs designed for eliminating pollution at a specific site, state officials said.
A variety of volatile organic compounds have been detected in the plume, but Department of Environmental Conservation officials said every home in its path has been connected to a public water supply, and vapor tests at four houses above the highest concentration of contaminants have shown none of the harmful levels of pollution.
The plume is in the underground water supply, and test wells have shown at least 30 feet of uncontaminated water above any detectable contaminant. Because the groundwater is 40 to 50 feet below the surface, homes are not in danger from contamination, state officials said.
But the reassurances were not enough for the people in the audience, who complained that the contaminants were heading for Moriches Bay, and would cover the distance from 2,000 feet south of Montauk Highway to the bay in another decade or so.