With the background of gray skies and a slight drizzle, a lone excavator shifted dirt Thursday off Route 11 in the village of Homer.
Crews overseen by New York State Electric & Gas Corp. have been working at the site near the former Cortland Homer Manufactured Gas Plant, removing contaminated sediments from the Tioughnioga River.
It’s one of an estimated 200 — maybe 300 — former manufactured gas plants in the state, all of which have been closed since at least the 1970s, according to the state Department of Environmental Conservation. The DEC reports that virtually any community with more than 5,000 residents had at least one manufactured gas plant. More than 200 of those sites are undergoing or have undergone remediation.
While the work is happening today, the plant closed almost 100 years ago and remediation investigation has been going back for almost half that time, some of the contamination remains.
The contamination of coal tar in the ground and water presents a health hazard to both humans and natural life.
To solve this, crews will clean a portion of the river until November before shifting downstream into the city of Cortland.
“It’s critical work that is being done,” said Homer Mayor Darren “Hal” McCabe.
A PROBLEM 160 YEARS IN MAkING
The site dates to 1858 when a building was constructed under the name Homer and Cortland Gas Light Co. to provide manufactured gas to the village of Homer, according to a 2007 report from the state Department of Environmental Conservation.
The gas produced at the site was used for heating and lighting in homes and businesses, the report said. Gas was produced on site using two processes: coal gasification and the carburetted water gas process.
The production of coal gas lasted until 1921 and the carburetted gas process from 1921 until 1932, when the site closed down, the report said.
Coal gasification, which produced coal gas, worked by heating coal pieces in ovens and then carbonizing the coal, the report said. The carburetted water process worked by having steam pass through burning coal, which then formed a gas before passing through a super heater. When going through the heater, the mixture would be soaked by an oil spray that would generate additional gas and enhance the heating and lighting capacity.
Both processes involved the gas being cooled and purified before being distributed.
It was during this cooling process that an oily substance known as coal tar would condense from the hot gas and settle to the bottom of gas holders, pipes and other devices used in the processes, the report said. When exposed to humans, coal tar can irritate eyes and skin on contact, according to the New Jersey Department of Health. Long-term exposure to coal tar has been shown to cause lung, kidney and skin cancer.
Manufactured gas plants generally had the gas holders and other devices used in the gas process stored underground for cooling and pressure purposes, the DEC reports.
“Hence these structures have a significant potential to introduce byproducts from the coal gasification and carburetted water gas processes directly into the site groundwater and subsurface.”
NYSEG partially decommissioned the site in the 1940s before Brockway Motor Co. bought it in 1944 and demolished the remaining structures, the report said. The building on the site is believed to have been built by Brockway and modified by later owners.
Between 1985 and 1991, NYSEG conducted investigations to find the source area of coal tar and related compounds in subsurface soils, according to the report.
Further remedial investigation would take place between 1999 and 2003 and involved work such as historical use of the property, subsurface soil sampling and surveying nearby public and private water supply wells.
Investigation of groundwater and soil found elevated concentrations of polyaromatic hydrocarbons, according to a 2021 report, both on the site of the former gas plant and in sediments in the nearby Tioughnioga River.
PAHs occur naturally in coal, crude oil and gasoline, according to the U.S. Centers for Disease Control and Prevention. While the effect on human health from low levels of PAHs in environmental exposure is unknown, large exposure to naphthalene — a commercially produced polycyclic aromatic hydrocarbon — can result in blood and liver abnormalities, the centers said.
“Several of the PAHs and some specific mixtures of PAHs are considered to be cancer-causing chemicals,” according to the centers.
Cleaning up the mess Work to clean up coal tar waste began in 2012 from crews overseen by NYSEG and lasted until 2013, said Kelly Packard, a NYSEG representative.
In March 2021, that work shifted to the Tioughnioga River, following the residue that traveled from the site into the waterway. Work then shifted onto the river itself in March, she said.
“This work is to dig out that contaminated sediment from the river and replace it with clean, imported material,” Packard said.
Crews overseen by NYSEG will be at the site until November, replacing contaminated soil in the river with clean soil. Other work, according to the 2021 DEC report, includes:
- Installing (and removing) temporary water bypass systems to allow for excavation and backfilling.
- Excavating 6,000 cubic yards of sediments from the river, at depths ranging from 1 to 5 feet.
- Dewatering, stabilizing, and transporting excavated sediment off-site for low temperature thermal desorption treatment or disposal as non-hazardous solid waste.
- Restoring the riverbed by backfilling the site with clean fill.
- Restoring the riverbanks and adjoining upland areas with appropriate topsoil and planting vegetation.
This work will cost $15.8 million, the report said. Environmental remediation projects like this are approved by the DEC and are paid for by customer delivery rates, Packard said.
The village of Homer is not involved in the work, beyond leasing the land to NYSEG, McCabe said.
Have crews found anything interesting while doing the cleanup work?
“Other than a few old bottles, no,” Packard said.
Beginning in March 2022, work will continue down the river in Cortland and continue until November, Packard said.
The cleanup work is nothing new in the state, McCabe said.
“Remediation of brownfields is a challenge no upstate New York community is immune to,” he said. “The main differences being those companies who do the bare minimum versus those who actually try and put the land back as it should be.”
The latter is what is happening with NYSEG’s help, he said.
During the work, crews found seams of contamination that ran underneath at least one of the properties the village recently bought as part of a planned linear park, McCabe said.
“Had this not happened during an active NYSEG cleanup, I am not sure what it would have taken in effort and time to get them to do a special project to remove a relatively small amount of material,” he said.
The village was also concerned about planting edible plants at the linear park and how remediation work might affect the vegetation. NYSEG said it would be careful about the work it was doing so the property could remain in healthy shape to grow plants.
“NYSEG has been very good to work with through all of this,” McCabe said. “And it is a huge net positive for us here in the Village of Homer.”