The U.S. Environmental Protection Agency released its initial list of Superfund National Priorities List sites with the greatest expected redevelopment and commercial potential on Wednesday, and New Bedford Harbor was among the 31 sites listed.

The EPA has been working to dredge the harbor since 2004, and has worked with the Army Corps of Engineers to perform multiple targeted cleanup actions to remove PCB contamination caused by improper disposal of industrial waste along the harbor from manufacturing plants.

In 2013, the EPA finalized a $366.25 million settlement with Aerovox, the main company responsible for the contamination. The agency says approximately 425,000 cubic yards of PCB-contaminated sediment has been removed from the Upper Harbor as of December 2017.

Previously, the agency completed dredging of approximately 220,000 cubic yards of less contaminated sediment in the Lower Harbor and Upper Harbor in 2016-17, followed by placement in the Lower Harbor CAD Cell. Another 25,000 cubic yards of contaminated sediment cleanup has been completed by EPA along the Harbor's shoreline.

The EPA estimates the majority of the cleanup will be complete within about five years.

In a release, it was stated that EPA Administrator Scott Pruitt "has set the expectation that there will be a renewed focus on accelerating work and progress at all Superfund sites across the country."

There are nearly 1,200 sites on the Superfund National Priorities List across the country, but New Bedford is considered to have some of the greatest redevelopment and commercial potential since it is already the nation's top fishing port. The EPA says it is working closely with the City and the state on a number of projects, including studies on the potential reuse of EPA shoreline support facilities, integrating navigational dredging with the construction of port facilities, and working with the City on the development of the Riverwalk planned along the Acushnet River and the Upper Harbor shoreline.

In his weekly appearance on WBSM, Mayor Jon Mitchell said the Riverwalk project is coming along, but it's progression depends on how quickly the EPA cleanup takes to complete.

"After the Riverwalk project started, the EPA settled with Aerovox, and received the payment of $366 million, plus interest," Mitchell said. "That money is being used to first clean up the upper harbor, and obviously, we shouldn't be building a Riverwalk along the river, if the EPA has to go back and tear it all up to get all the contaminated sediment out. So it has to wait for the EPA to finish that part of the harbor, and they are moving along very well."

Mitchell said he is very pleased with the pace of the EPA's cleanup effort thus far.

"Overall, yes, I am," he said. "They've been working very closely with us. We had a big milestone a few months ago, when they allowed us to go forward with the permitting of the North Terminal project, and we need funding for that. The EPA has been great working with us to get to that point."

Although the mayor said it could take between three and five years for the Riverwalk to be completed, he thinks it will be a huge asset to the city once it is done.

"I think it's going to do wonders for a lot of the North End, to have a real great public amenity like that, the same way the Covewalk and the Harborwalk have done for the peninsula," he said. "It's really going to add a lot."