The inventory of pollutants at the bottom of the Passaic River, which meanders for 90 miles through northern New Jersey, is long and truly frightening. More than a century of industrial activity has deposited PCBs, pesticides and other contaminants into sediment that, in some places, is 15 feet deep. Among the worst of the poisons is dioxin, generated in part by a plant in Newark that produced Agent Orange and other deadly pesticides during the 1960s.

Now, after years of study, the Environmental Protection Agency has proposed a cleanup plan for a dangerously fetid eight-mile stretch from Belleville to Newark. This will be no small task. The agency calls it the largest cleanup in the 33-year history of the federal Superfund law, with a projected cost of $1.7 billion that puts it in roughly the same range as General Electric’s cleanup of the PCB’s in the upper Hudson River.

The E.P.A.’s plan is ambitious, necessary, long overdue and definitely good news for those who believe that humans should again enjoy this once-thriving waterway. It also shows that Superfund, in which Congress has shown steadily declining interest, still matters when it comes to the long and difficult battle against industrial leftovers. The cleanup has bipartisan support in New Jersey, including from Gov. Chris Christie, a Republican, and Democratic members of Congress.

If approved, after a 60-day public comment period, the project would involve bank-to-bank dredging to remove 4.3 million cubic yards of contaminated sediment, after which the river bed would be capped. The task would take at least five years, and — according to Judith Enck, the agency’s regional administrator — it would mean excavating enough contaminated mud to fill New Jersey’s MetLife Stadium, twice over.