Officials had to shut down several popular beaches in Maryland, Delaware, and Virginia after medical waste washed ashore.

Some of the medical waste included needles, Fox News reported on Sunday.

“Swimming was prohibited at beaches that included Ocean City, Maryland, and Fenwick Island, Delaware, and both state and federal beaches on Assateague Island, which is part of Maryland and Virginia,” the outlet said.

The emergency services team with the Town of Ocean City quickly addressed the problem and told visitors the beach was temporarily closed to swimmers. Officials also urged people to wear shoes on the beach and avoid the water as an investigation into the issue progressed.

Ocean City and Assateague Island eventually reopened to swimmers, WTOP News reported on Friday.

“In a message posted Friday, Emergency Services Director for the Town of Ocean City Joe Theobald said, after several days of multiple high tides and beach sweeps, it is no longer ‘experiencing waste washing ashore.’ He added that tests show that the water levels are normal,” the article read.

The outlet noted that the North End of Assateague Island was still closed and could remain closed for a longer period of time amid the cleanup. Officials were still working to find the source of the waste.

Video footage shows some medical waste at the Ocean City beach, and visitors shared their concerns with a reporter from WTKR:

The beach at Fenwick Island was closed to swimmers, and authorities urged people to wear shoes in order to avoid stepping on any needles that might have washed ashore, the Fox article said.

“As of Thursday, rough seas continued to be a hazard for swimmers, though officials had not updated the town’s social media channels to say whether medical waste remained an issue,” per the report.

The U.S. Environmental Protection Agency (EPA) defines medical waste as a “subset” of refuse from places such as hospitals, doctor’s offices, veterinary facilities, and laboratories.

“Medical waste is primarily regulated by state environmental and health departments. EPA has not had authority, specifically for medical waste, since the Medical Waste Tracking Act (MWTA) of 1988 expired in 1991,” the agency said.

“Concern for the potential health hazards of medical wastes grew in the 1980s after medical wastes were washing up on several east coast beaches. This prompted Congress to enact The MWTA of 1988,” it stated.