For decades, an unknown amount of PCBs dumped into the upper Hudson River by General Electric has been carried by the tide 150 miles south to the increasingly populated waterfronts of Bergen and Hudson counties.

But the true extent of contamination in New Jersey's portion of the river has never been known. That may change.

Under a legal agreement reached Tuesday with the U.S. Environmental Protection Agency, GE will begin testing fish, water and sediment from the lower Hudson for contamination.

Although sampling locations have not yet been determined, the project calls for testing to occur along the 20-mile portion of the river in New Jersey, said Larisa Romanowski, an EPA spokeswoman.

"This is something we've been asking them to do for close to 20 years," said Gil Hawkins, environmental director of the Hudson River Fishermen's Association. "New Jersey gets forgotten a lot in this conversation, but this now puts the spotlight on us. And that's a good thing."

The project is set to begin in early 2023 and would last until at least 2024. EPA Regional Administrator Lisa Garcia said the data would help the EPA determine what future actions to take with the river.

While some hope it could eventually lead to another large-scale river cleanup, the project's lack of a budget or specific sampling sites has drawn some concern from environmentalists.

"We're happy this is happening, but what we really need to find out is just how extensive this testing is," said Greg Remaud, executive director of the NY/NJ Baykeeper. "We're always wary of New Jersey getting the short end of the stick. We want to make sure it gets the same attention that the rest of the river is getting."

The agreement requires GE to submit a cost estimate for the work that has to be approved by EPA, Romanowski said.

The pollution dates back to 1947 when GE began releasing into the Hudson about 1.3 million pounds of PCBs used to lubricate machine parts at factories in Fort Edward and Hudson Falls, New York. PCBs have been shown to cause cancer, as well as diseases of the immune, reproductive and nervous systems.

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For the lower Hudson, a critical moment occurred in 1973, when a decaying dam was removed 40 miles north of Albany, New York, and large quantities of PCBs began flowing downriver. The EPA has estimated that 500 pounds of PCBs has flowed annually for decades over the Troy Dam in New York to the lower Hudson where the tide carries it to New Jersey and beyond.

GE finished a $2 billion cleanup in 2015 that removed 2.8 million cubic yards of polluted river mud — enough to fill two football stadiums.  

At the time, EPA officials said they were confident the cleanup would help decrease the amount of PCBs along the shores of Palisades Interstate Park, Fort Lee, Edgewater, Weehawken, Hoboken, Jersey City and the rest of New Jersey's section of the river, which has seen an explosion in residential development over the past 25 years. 

But environmental groups, New York officials and even some federal agencies called for the company to continue dredging lower portions of the river. EPA officials were hesitant at the time.

The new project will take sediment samples at three different depths of the river bottom to help the EPA better understand where PCBs have been deposited over time. 

Another key component will be testing fish — the most direct way humans come into contact with Hudson River PCBs.

New Jersey officials advise against eating more than a minimal amount of fish caught from the Hudson because of decades of industrial and sewage contamination. But anglers, many of them new immigrants, can be found along the Hudson casting their lines from Bayonne to Fort Lee, especially in warmer months. 

"It would be great if someday we would be able to catch fish out of the Hudson and not worry about eating it," Hawkins said.