A blockage in a sewer pipe prevented sewage from reaching the Lopes Field pumping station, causing an overflow on to West Boulevard in Onset on Saturday, Jan. 12.

According to Wareham Harbormaster Garry Buckminster, the Mass. Division of Marine Fisheries notified him at 12:30 p.m. Wednesday, that most of the areas that were shut down are safe to reopen for shellfishing.

Sunset Cove and Agawam Beach will remain closed for the rest of the week.

"This is only a precautionary measure to allow for adequate water flushing of the immediate area that was directly impacted," said Buckminster.

Buckminster said he will notify the public when the remaining two areas are reopened for shellfishing.

The Division of Marine Fisheries closed numerous areas in Onset to shellfishing due to the spill.

Water Pollution Control Facility Director Guy Campinha appeared before the Board of Selectmen on Tuesday and said he believes that the main cause of the blockage was people flushing things down the drain other than toilet paper.

“I got a [stuffed] beaver. How’d that get through?” he said.

Campinha said that while clearing the blockage, workers found grease, wires, paper products, and various building materials. According to Campinha, it took 5½ hours to clear the blockage.

“We’re going to step up education about grease in the system,” said Campinha.

Campinha said that cameras will be installed at the location of the blockage in order to ensure that the system in the area is structurally sound.

Selectmen Chair Steve Holmes praised Campinha for the way he handled the situation, but said he felt the board – which also serves as Sewer Commissioners – should have been notified sooner.

“This information needs to get out,” said Holmes.

The Wareham Harbormaster Department and Division of Marine Fisheries will monitor water quality and provide updates as information becomes available.