Water and land

Water, Ash, and the Contamination Record

Plainfield’s public drinking water is drawn from the ground, not from a reservoir. The residues that waste-gasification and incineration plants produce — fly ash, bottom ash and process leachate — are documented in the peer-reviewed literature to carry leachable heavy metals and, in the regulatory record, to have reached groundwater at comparable sites. This page sets those two facts side by side, using primary sources.¹¹⁴

Two questions, answered from the record. First: where does Plainfield’s water actually come from? Second: at facilities and processes like the one proposed, what have the ash and leachate done to groundwater elsewhere? Each precedent below is labeled as a comparable precedent, not a prediction, and each is anchored to its primary EPA, CT DEEP, USGS or peer-reviewed source.

Part one

Where Plainfield’s Water Comes From

Plainfield does not draw its public supply from a surface reservoir. The relevant water here is groundwater — the same water body under and around the proposed site.

• The public water system serving Plainfield — Connecticut Water’s Plainfield System, state identifier CT1090081 — draws its supply from groundwater wells, not from a surface-water source.¹
• CT DEEP identifies Connecticut’s stratified-drift deposits, including those of the Quinebaug River basin, as the “most productive aquifers in State… especially where thick, coarse grained, and hydraulically connected to large streams or lakes.” By contrast, the state’s bedrock yields only “adequate supplies for domestic use.” The large-yield water under this region is the stratified-drift aquifer.²
• The scale of that aquifer is measurable. The State of Connecticut’s own Quinebaug Valley State Trout Hatchery, in Plainfield, draws 1,290,816,000 gallons of groundwater a year from 12 high-volume wells operating around the clock. A 2023 state project to conserve between 632 million and 946 million gallons a year is described by CT DAS and DEEP as “significantly reducing the stress on the aquifer.”³
• In the rural corridor around the site, homes outside the Connecticut Water service area draw their household supply from private groundwater wells tapping that same subsurface water.¹²
• CT DEEP has an Environmental Justice Public Participation Plan on file for the SMART Technology Systems project at Norwich Road and Black Hill Road. Under Connecticut General Statutes § 22a-20a, a proposed “affecting facility” in an environmental-justice community must file a meaningful public-participation plan in connection with its permit application.⁴⁵

What is not claimed. This page does not assert that the parcel sits within a state-designated Aquifer Protection Area. Plainfield’s designated protection areas cover other parts of town, and parcel-level status is not established here. The verified point is narrower and firmer: the region’s water is groundwater, and it is the aquifer that supplies wells and the state hatchery.²³

Part two

What the Residues Contain

Waste-to-energy plants of this kind do not make their input disappear. They convert it into flue gas, energy, and solid and liquid residues — fly ash, bottom ash or slag, and process leachate. What those residues contain is established in the peer-reviewed literature and the federal regulatory record.

• A 2025 peer-reviewed review in the journal Toxics states that municipal-solid-waste incineration fly ash “is recognized as a hazardous solid waste due to its enrichment in toxic heavy metals and high leaching potential,” naming lead, cadmium, chromium, arsenic, mercury, nickel, copper, zinc and others, alongside chlorides and dioxins. The same review notes that in landfills these pollutants “could migrate through various pathways such as leachate transport, groundwater diffusion, and plant uptake.”¹⁴
• The U.S. EPA has made coal-combustion residuals a formal National Enforcement and Compliance Initiative — “Protecting Communities from Coal Ash Contamination” — citing the “long-term release of contamination into groundwater, drinking water, or surface water.” The heavy metals of concern in coal ash (arsenic, cadmium, chromium, mercury, lead) are the same class found in municipal-waste combustion ash.¹¹¹⁴
• Waste gasification and pyrolysis are regulated as waste incinerators in the United States and the European Union, because the synthetic gas they produce is ultimately combusted; the process is distinct from mass-burn, but the residue and emission concerns are not eliminated by the name.¹²¹⁶

The residues are not the argument. What the residues have done, in the documented record, is.¹⁴

Part three

The Contamination Record

Precedent, not prediction

Each entry below is a documented, comparable precedent — a real facility or process whose groundwater outcome is on the primary regulatory or scientific record. None is offered as a forecast of what the Plainfield proposal would do. Each is offered as evidence of what this class of facility has done, so the risk can be weighed on facts rather than assurances.

In Plainfield: Gallup’s Quarry

Plainfield already has one federally documented groundwater-contamination site — and a gasification plant already operates on part of it.

• Gallup’s Quarry is a 29-acre former gravel pit in Plainfield placed on the EPA Superfund program after illegal chemical dumping. Groundwater, soil and sediment there carry volatile organic compounds, PCBs and heavy metals; arsenic and 1,4-dioxane were added to monitoring in 2012, and PFAS compounds were detected during the November 2020 groundwater sampling event. The remedy relies on long-term monitoring and institutional controls that restrict use of the contaminated groundwater.⁶
• Part of that same Superfund site is now home to the Plainfield Renewable Energy biomass gasification facility, which “became fully operational in January 2014.” Plainfield’s only documented groundwater-contamination site already hosts one gasification plant; the SMART proposal would add a second, larger one taking in mixed municipal waste.⁷

On Plainfield’s river: the Putnam ash landfill

• A 2021 CT DEEP adjudication decision documents the Wheelabrator / Waste Innovations ash landfill in Putnam, on the Quinebaug River — the same river system as Plainfield — which receives ash from Connecticut’s trash-to-energy incinerators. Its leachate is sent to the Putnam water pollution control facility, and the decision addresses first-time PFAS testing of that leachate and site groundwater. Ash from a new Plainfield plant would enter the same disposal stream on the same river.⁸

Coal gasification, decades on: Mason City and Waterloo, Iowa

Two former coal-gasification plants show how long groundwater damage can persist — and that in one case the federal government has declared it beyond cleanup.

• Mason City, Iowa (operated 1900–1951): coal-tar contamination reached both the shallow and the deeper aquifer. EPA’s April 2023 five-year review found that in the deeper aquifer, “levels of benzene and benzo(a)anthracene were increasing at some locations” — more than seventy years after the plant closed.⁹
• Waterloo, Iowa (operated 1901–1956): contamination was severe enough that EPA “determined that it was not feasible to clean up all of the groundwater contamination” and designated a “technical impracticability zone.” The groundwater there “is expected to remain contaminated for the foreseeable future.”¹⁰

PFAS from combustion: Norlite, New York

• At the Norlite incinerator in Cohoes, New York, which burned PFAS-laden firefighting foam under federal contract, Bennington College sampling reported by The Intercept found PFAS in soil and water around the plant, with PFOS measured “twice as high downwind from the facility than upwind of it.” The plant sits less than 200 meters from a public-housing complex home to more than 70 families; New York regulators directed a halt to the foam incineration, and the State subsequently enacted a law banning PFAS-foam incineration in cities including Cohoes. This is an academic sampling result reported in the press, presented here as such; the regulatory action is on the official record.¹³¹⁷

The national pattern: coal ash and groundwater

• The most comprehensive national analysis of federal coal-ash monitoring data, by the Environmental Integrity Project with Earthjustice, found that 242 of 265 monitored U.S. coal plants — about 91 percent — had unsafe levels of at least one coal-ash pollutant in nearby groundwater, including arsenic, lithium, cobalt and cadmium. The same heavy metals appear in municipal-waste combustion ash.¹⁵¹¹

Questions and answers

Frequently Asked Questions

Where does Plainfield get its drinking water?

Plainfield’s public water system (CT1090081) draws from groundwater wells, and homes in the rural corridor outside the service area use private groundwater wells. The relevant water body is the aquifer, not a surface reservoir.¹²

Is the proposed site on a designated Aquifer Protection Area?

That is not established here and is not claimed. What is documented is that the region’s water is groundwater from the productive stratified-drift aquifer that supplies wells and the state trout hatchery.²³

Does gasification or incineration ash contain contaminants that can reach groundwater?

The peer-reviewed literature classifies municipal-waste incineration fly ash as a hazardous waste “due to its enrichment in toxic heavy metals and high leaching potential,” and notes those pollutants can migrate through leachate and groundwater. EPA treats coal-ash groundwater contamination as a national enforcement priority.¹⁴¹¹

Has a gasification plant ever contaminated groundwater beyond repair?

At the former Waterloo, Iowa coal-gasification site, EPA determined full groundwater cleanup was not feasible and designated a “technical impracticability zone” expected to remain contaminated for the foreseeable future.¹⁰

Does Plainfield already have a documented contamination site?

Yes. Gallup’s Quarry is an EPA Superfund site in Plainfield where PFAS was detected in November 2020 groundwater sampling; a biomass gasification plant now operates on part of it.⁶⁷