The Long Island Rail Road will excavate more than 4,750 tons of contaminated soil at seven substations in Queens and Nassau County this year and into early 2016 to remove mercury, lead and other toxins.
The work is part of an $11 million capital plan program the LIRR started in 2010 to clean up 20 sites from Shea Stadium to Babylon.
The contamination dates back to the early 1930s through 1951, when the LIRR used tubs of mercury at substations to help convert alternating current into direct current to power locomotive and passenger cars.
The rectifiers that converted the power were removed in the 1980s and replaced, but the contamination remained.
The new cleanup was prompted when a worker saw mercury beads in the corner of a building in the late 1990s, said Andrew Wilson, LIRR director of the Department of Program Management.
"It was just poor housekeeping," Wilson said of the contamination.
The LIRR conducted environmental investigations between 1999 and 2000 and agreed in the 2000s with the state Department of Environmental Conservation to enter a voluntary cleanup program.
Remediation consists mainly of soil excavation. "Mercury doesn't like to travel too far," Wilson said.
The element occurs naturally, and most common exposures come from eating contaminated fish or shellfish. High exposures can damage the nervous system, brain, heart, kidneys, lungs and immune system, according to the U.S. Environmental Protection Agency.
"It's a dangerous chemical, but it can be remediated," said Adrienne Esposito, executive director of Citizens Campaign for the Environment, based in Farmingdale.
Ten sites have already been cleaned up. On deck are substations at Shea Stadium, Kew Gardens, Port Washington, Manhasset, Valley Stream, Island Park and Hempstead.
The DEC comment period on the plans in Hempstead, Island Park, Valley Stream and Manhasset have ended. Once DEC approves a work plan, the LIRR can begin. Each site should take about four weeks to remediate, Wilson said.
Prior investigations found varying levels of contaminants. At Hempstead a hot spot showed 17.6 milligrams per kilogram of mercury, while the industrial safety standard is 5.7 milligrams per kilogram.
When the work is completed by early 2016, an estimated 3,800 cubic yards of contaminated soil will be removed. That amount is equivalent to about 2,065 Toyota 4Runners.
By 2018 the final three sites in Bayside, Cedar Manor and Far Rockaway should be completed, Wilson said.
Groundwater contamination has not been found at any of the sites, and rail traffic should not be affected.
The sites are all fenced off or at right-of-ways not open to public, LIRR spokesman Salvatore Arena said.
"Most of these LIRR sites have very limited access due to the nature of the site activities," DEC said. "The cleanups are consistent with industrial or commercial use of these properties, with consideration of the surrounding land use."
The contaminated soil will be trucked away to a permitted off-site facility in tarp-covered trucks, and equipment will be decontaminated.