GUILDERLAND — A piece of property in Guilderland contains so much mercury it has been placed on the federal Environmental Protection Agency’s National Priorities List, meaning it is one of the most contaminated sites in the country.

The half-acre piece of land, located on Railroad Avenue off of Fuller Road, partially in Guilderland and partially in Colonie, used to be owned by Mercury Refining Company, Inc, also known as MERECO, now defunct.

Currently, a cleanup project for the land is being designed, and actual cleanup is slated to start in 2013, according to EPA spokeswoman Larisa Romanowski.

Romanowski said the site is on the EPA’s Superfund list, which means potentially responsible parties will provide funding for the cleanup.

“Basically, the polluters will pay,” said Romanowski.

As of Sept. 30, 2009, the EPA had signed agreements with seven potentially responsible parties, and issued an administrative order to two other parties, requiring them to participate and cooperate.

The EPA also signed an administrative consent order with 291 other, smaller potentially responsible parties, and settled with each, for a total amount of $3.7 million to go toward the cleanup.

The Mercury Refining Company, which reclaimed mercury from batteries, thermometers, and other materials, closed in 1998, but not before the state’s Department of Environmental Conservation spent 15 years investigating and removing contaminated soil from the area.

When the DEC requested that the EPA take over the cleanup in 1999, the federal agency performed its own investigation.

Approximately 20,000 people live within a one-and-a-half mile radius of the site, and 100,000 people live within three miles; the closest residents live one-quarter mile from the site.

A health-risk assessment from the EPA found there was a significant potential risk from direct exposure to the mercury-contaminated soil and groundwater, and an ecological-risk assessment found the potential risk to ecological receptors in a nearby tributary was “unacceptable.”

“It appeared that material had been dumped over an embankment,” Romanowski this week. 

An unnamed tributary merges into the Patroon Creek, and then, five miles downstream, flows into the Hudson River.

Once mercury enters soil and water, it can be converted to methyl mercury, which can be absorbed quickly by organisms and can cause nerve damage, as well as kidney damage, stomach problems, and reproductive failure.

Investigations by the DEC showed that batteries and other materials containing mercury were dumped behind a furnace building on the site until 1980. After 1980, they were stored in drums on wooden pallets on paved areas.

DEC tests revealed that the waste was at least three feet beneath the surface of the ground, and stream sediment tested high in both mercury and polychlorinated biphenyls (PCBs).

In 1985, the DEC excavated and removed some of the contaminated soil. In 1989 a new container storage building was added to the site, and, in 1994, new retorts — closed vessels used for decomposition by heat — were installed.

The town of Guilderland’s zoning board of appeals approved a variance for Mercury Refining in 1988, for a building to cover drums of hazardous waste that were being stored on concrete pads.

“There’s not too much appealing about this whole matter,” said then-chairman of the board, Tim Sheehan, at the time. The zoning code in the 1980s prohibited storage of hazardous waste, but, Mercury Refining had been in business since 1955, before the code was established, so it was grandfathered in.

The board was aware of, and discussed, the fact that the DEC had been investigating and cleaning up the site.

Though zoning board members were uncomfortable with the idea of the presence of mercury in the town, they approved the structure because they felt it provided a certain measure of safety, and the DEC had already capped one storage pad with clay and installed groundwater monitoring wells.

“It will provide better protection for the people of Guilderland and the materials that are stored there,” said board member John Smircich at the time.

A hazardous waste corrective action permit was issued by the DEC to Mercury Refining Company in 1996, requiring the company to remove contaminated soil under an old furnace building, and to perform long-term monitoring of soil and groundwater on site, and sediment in the Patroon Creek.

The company repeatedly failed to comply with the permit, leading to the DEC’s request for the EPA to take over as the lead agency.

Mercury Refining Company did not have enough funding to perform a remedial investigation and feasibility study, so the EPA performed both, and issued a record of decision in 2008.

The decision specified that mercury-contaminated soil above the water table must be excavated, mercury-contaminated soil beneath the water table must be treated, and mercury-contaminated sediment must be removed from the unnamed tributary.