Hurricane Matthew unearthed these cannonballs from the time of the Civil War on a beach near Charleston, S. C. (CHARLESTON COUNTY SHERIFF’S OFFICE VIA EUROPEAN PRESSPHOTO AGENCY)

A pile of Civil War-era cannonballs was uncovered by Hurricane Matthew this month after the storm lashed South Carolina. But rather than preserve the artifacts, authorities destroyed most of the historic weapons for safety reasons.

A day after the hurricane blasted the coastline on Oct. 9, a resident walking along the east end of Folly Island — a coastal region known for its history of pirates and Civil War battles — spotted 16 corroded cannonballs resting on the sand, said Andrew Gilreath, director of public safety for Folly Beach, a small city about 10 miles south of Charleston. The resident contacted authorities, who came to assess the situation, he said.

The hurricane’s waves and winds probably eroded parts of the beach to uncover the bowling-ball-size weapons, Gilreath said.

“Initially, the city wished to display them,” Gilreath said in an email. “However, they were inspected and a large number of them were [found to be] explosive cannonballs, and thus contained old and very unstable gunpowder.”

It’s a common misconception that cannonballs are merely large steel balls, he said. “While that is the case sometimes, there are also explosive and incendiary types, which are very unsafe,” Gilreath said.

After inspecting the cannonballs, authorities decided to destroy them. According to a tweet from the Charleston County Sherriff’s Office, local officials worked with an Air Force explosives team to dispose of the ordnance.

LowCountry CW, a Charleston news network, warned that “residents in Charleston, James Island, and on Folly Beach may hear what will sound like an explosion.” It also reported that once ocean levels go down, technicians would ensure that the area where the cannonballs were found is safe.

One of Folly Island’s historical moments was portrayed in the 1989 movie “Glory,” which tells the story of a military unit of all-black volunteers fighting for the Union.

The battle portrayed in the movie was fought at Fort Wagner, “which is more than likely what this artillery was used to fire upon,” Gilreath said of the pile of cannonballs.

The first shots of the Civil War were fired not far away, at Fort Sumter, in 1861.

— Live Science