INDUSTRY LEFT MERCURY IN WAPPINGER CREEK. WHY THE HELL IS IT STILL THERE?

EPA is proposing an $88.1 million interim remedy for the upper portion of a two-mile Superfund site. It would remove some of the creek's worst contamination. It would not finish the cleanup.

People have been manufacturing things beside Wappinger Creek since the early 1800s: hats, bleached cloth, metal plating, ammunition and chemicals. The factories changed names, closed and, in some cases, disappeared.

The mercury stayed in the mud.

Now the U.S. Environmental Protection Agency is proposing a major removal project for the creek's two-mile tidal Superfund site. Its preferred plan would dredge mercury-contaminated sediment, excavate polluted soil along the banks, truck the material to approved off-site disposal facilities and rebuild the disturbed creek bed with clean backfill and a habitat layer.

The estimated present-worth cost is $88.098 million. The work would take about 19 months, spread across three years.

And it still would not clean up the entire site.

That is the part most likely to disappear beneath words such as remedy, operable unit and interim remedial action. After more than 180 years of industrial use, EPA is proposing to remove a major source of mercury from the upper creek. The downstream portion would remain for a later decision.

Interim is the word doing the most work here.

The factories left. The mercury did not.

EPA defines the Superfund site as the tidally influenced lower two miles of Wappinger Creek, beginning at the base of Wappingers Falls near the Market Street Industrial Park and ending where the creek meets the Hudson River.

Industrial operations beside the creek included cloth dyeing, a manufactured gas plant, felt-hat production, metal plating, plastic molding, chemical manufacturing and ammunition production. Wastewater and manufacturing byproducts moved through channels, lagoons and direct discharges into the creek.

At one metal-plating operation, wastewater flowed through the Three Star Lagoon and into Wappinger Creek at an estimated 20,000 to 60,000 gallons a day from 1958 to 1980.

Here is the maddeningly short answer to the headline: state regulators documented trouble at the site in 1971. Three Star Anodizing was required to obtain a state discharge permit in 1975. EPA did not add Wappinger Creek to the federal Superfund list until 2016, and this proposed dredging remedy arrived in 2026.

The creek has been moving at the speed of water. The cleanup has been moving at the speed of government.

EPA is now proposing what it calls Alternative 4 for the upstream portion: remove contaminated sediment and streambank soil wherever total mercury exceeds 1.1 milligrams per kilogram, then backfill the excavated areas to their previous grade.

That threshold is not decorative paperwork. Depending on the location, EPA estimates dredging could reach from one foot to 5½ feet deep.

What EPA wants to dig out

The proposed work focuses on three upstream sections: the Industrial Park, Upper Shoal and Embayment. Together, they cover transects 1 through 17, ending above the lower portion of the site where tidal sediment exchange with the Hudson becomes more influential.

Those upstream areas contain mercury-contaminated material EPA believes can move through the creek. The streambanks are included because polluted soil could erode and contaminate the creek bed again after dredging.

Removed sediment and soil would be managed, treated when necessary and transported to permitted off-site disposal facilities. EPA would place clean backfill and a habitat layer in the excavated areas so the rebuilt creek bottom matches its former grade.

In plain English, this is not a plan to cover the worst sediment with a reactive cap and hope that cap behaves forever. EPA's preferred alternative would remove every targeted area above the interim mercury threshold. The agency says it would take out the greatest amount of mercury source material among the options it studied.

It is also the most extensive dredging option, which means getting the contamination out creates a second problem: how to perform heavy construction inside a shallow, tidal creek bordered by homes, businesses, roads, rail, bridges and limited shoreline access.

Three years of cleanup will not be a quiet neighbor

EPA estimates 19 months of construction spread over three years. During that time, nearby residents and creek users could see more truck traffic, noise, dust, possible odors and temporary restrictions on parts of the waterway.

Dredging can temporarily stir sediment, cloud the water and disturb habitat and aquatic species. The proposal says those effects could be reduced through haul-route planning, restricted work hours, signs, flaggers, dust suppression, air monitoring and other construction controls.

The physical setting makes the job harder. Parts of the creek are shallow and tidal. Bridges have limited clearance. Overhead utilities and scarce shoreline access complicate the movement of dredging equipment. Water removed from contaminated sediment may need to pass through a temporary treatment system, and staging space near the creek is limited.

This is what disappears when a cleanup is reduced to a tidy sentence about removing pollution. Removing pollution means machinery, trucks, water treatment, temporary habitat loss and years of work beside a creek people still fish, paddle and swim in.

EPA's investigation also found total mercury and methylmercury in every fish it collected during a limited sampling program. The proposed remedy includes public outreach about the existing New York State Department of Health fish advisory for Wappinger Creek.

The creek remains an active recreational fishery and is designated significant coastal fish and wildlife habitat. EPA expects removing contaminated source material upstream to reduce downstream migration and the possibility of mercury continuing to build through the food web.

After construction, monitoring may include fish tissue, sediment, soil, surface water and pore water. That monitoring is not an afterthought. It is how EPA plans to evaluate whether this first project works and what contamination still remains.

The $88.1 million number needs an asterisk

EPA estimates the preferred plan's capital cost at $83.072 million, with annual operation and maintenance costs of $464,000. The $88.098 million figure is the estimated present-worth cost, which incorporates longer-term costs rather than describing one construction check somebody will write on Tuesday morning.

It is still an engineering estimate. EPA says the eventual cost could land 30 percent below or 50 percent above that figure.

New York's Department of Environmental Conservation concurs with the preferred alternative. Community acceptance has not been decided because the public-comment period is still open. EPA says public comments or additional data could change the preferred plan or lead the agency to choose another alternative.

The creek still has a second chapter

EPA divided the site into two anticipated operable units so work on the most contaminated upstream source area could begin before every downstream question is settled.

The current proposal covers Operable Unit 1. It does not provide the final remedy for the full two-mile site.

After the interim work, EPA expects to study fish tissue, sediment, soil and water; evaluate changes over time; look for ongoing contamination sources; and assess the creek's natural recovery. Those findings would shape a later decision for Operable Unit 2 and the final sitewide cleanup.

That means the preferred plan could remove an enormous amount of mercury-contaminated material and still leave Wappinger Creek with unfinished business downstream.

Both things can be true. It can be a serious cleanup, and it can be only the first one.

What residents can do before September 21

EPA extended the public-comment deadline from August 21 to September 21, 2026, at the community's request.

Written comments may be emailed to Wong.Emily@epa.gov or mailed to Emily Wong, U.S. Environmental Protection Agency, 290 Broadway, New York, NY 10007.

A useful comment does not need to sound as though it was written by an environmental attorney. Residents can ask about truck routes, construction hours, creek access, air and water monitoring, fish and wildlife protection, staging areas, how test results will be shared and what conditions would force the agency to change course

EPA will review the comments before selecting the remedy and will respond to them in the official decision record.

After more than 180 years, nobody should mistake this major removal project for the end of Wappinger Creek's story. But it could be the moment the creek finally stops being asked to hold all of that industrial history in

Sources

• EPA's proposed interim cleanup announcement

• EPA's full proposed plan for Operable Unit 1

• EPA's community update

• EPA's September 21 comment-period extension

Hero photograph: Wappinger Creek at its Hudson River mouth, inside EPA's defined two-mile Superfund site. EPA's proposed interim excavation targets the upper portion of the site, upstream of the photographed location. Photograph by Daniel Case via Wikimedia Commons, licensed under CC BY-SA 4.0. Cropped and color-graded by Hudson Valley Happenings. The cover adaptation is also licensed under CC BY-SA 4.0.