The sand bar is known as Shelly Island and is about a mile long.
The U.S. Navy's Explosive Ordnance Disposal (EOD) unit team leader from Little Creek, Virginia gave the all clear on Friday evening.
Shelly Island has been making headlines since popping up earlier this summer.
The military bomb disposal team checked out the object, which is heavily encrusted with marine growth and had clearly been in the water for some time.
The EOD unit determined that the item was a World War II-era training ordnance. The item is being taken to Virginia for further examination and disposal.
"The National Park Service appreciates the U.S. Navy's and U.S. Coast Guard's role in keeping park visitors and nearby vessels safely away from the unidentified item while it was being examined and removed by the EOD unit," said Outer Banks Group Superintendent David Hallac. "We also appreciate our partnerships with the Dare County Sheriff's office, Hatteras Island Rescue Squad, and N.C. Wildlife Resources Commission in keeping everyone safe."
The island is separated from Hatteras Island by a few hundred feet of water, which is no more than 5 feet deep at low tide.
Experts say the island could continue to grow, or it could suddenly vanish with the next big storm.
MORE: Warning about new island that popped up along North Carolina coast