For decades, Keyspan’s big blue gas ball on the Sag Harbor waterfront was a waypoint for mariners heading home to sheltered waters and a curiosity for sightseers, towering over Bridge Street and West Water Street in the village.
The gas storage ball, known in the industry as a Hortonsphere, was removed from the site a decade ago as part of a massive New York State Supervund cleanup of a thick layer of tar that had seeped into the ground below the site, but it wasn’t until this week that the New York State Department of Environmental Conservation deemed the site to no longer present a risk to the public.
The Sag Harbor gas ball was the among the last Hortonspheres in the nation to be taken down. A Hortonsphere on Railroad Avenue in East Hampton was the final one to be removed in 2013.
The Sag Harbor gas ball stood on the site of a manufactured gas plant that operated there from 1859 through 1931, which used coal to create gas fuel, but left behind a tar residue that seeped 10 feet down into the soil underneath the site, a remnant of Sag Harbor’s industrial past.
The DEC announced Dec. 5 that the site has been reclassified as a Class 4 Inactive Hazardous Waste Disposal Site, which “no longer presents a significant threat to public health.”
During the cleanup, undertaken by National Grid, a whole block of shops was demolished and more than 14,000 cubic yards of tar-contaminated soil were removed, to a depth of 10 feet. After the contaminated soil was trucked off site, the excavated areas were backfilled with clean fill and recovery wells were installed to collect any remaining tar, according to the DEC, which approved the 2006 Record of Decision selecting the remediation at the site.
The DEC says that three tax parcels on the site of the remediation will continue to be monitored through a Site Management Plan, while environmental easements have been placed on neighboring properties if further remediation is needed.
The environmental easements allow remediation of vapor from the contamination, restrictions on use of untreated groundwater in the neighborhood, and a prohibition on vegetable gardens and farming and on disturbing the soil at the site.
The easements also require that the property at 31 Long Island Avenue and 11 Bridge Street only be used for commercial or industrial purposes, and that 5 Bridge Street only be used for residential, commercial or industrial use.