MOUNT PLEASANT, S.C. – Federal and state authorities investigated the possibility there was a "dirty bomb" on a ship at a local terminal, but later gave the all-clear, reports CBS Charleston, S.C. station WCSC-TV.

Coast Guard officials say the FBI and other agencies were on-scene.

The terminal was evacuated while the threat was checked out.

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A dirty bomb is made from conventional explosives and radioactive material.

Fourteen agents were on board with radiation detection technology, WCSC says.

#update Unified Command determines no existing threat to the port. Terminal will reopen & safety zone has been lifted. — USCGSoutheast (@USCGSoutheast) June 15, 2017

#update there were 4 containers where threat was posed at terminal in Charleston, SC. These have been scanned and cleared by authorities. — USCGSoutheast (@USCGSoutheast) June 15, 2017

#update the original reporting source of the threat in port of Charleston has been detained by authorities for further questioning. — USCGSoutheast (@USCGSoutheast) June 15, 2017

A Coast Guard statement says authorities were made aware at 8 p.m. of a potential threat in a container aboard the vessel Maersk Memphis, and a one nautical mile safety zone mentioned in one of the tweets above was established around the vessel.

"The Maersk Memphis is currently moored at Charleston's Wando terminal, which has been evacuated while bomb detection units from federal, state and local law enforcement agencies investigate the threat," the Coast Guard initially said.

The ship's owner, the Maersk Line, a U.S. corporation, said in a statement to CBS News that all crew embers were safe on shore.

Maersk says the Maersk Memphis is a container vessel built in 2007.

The Coast Guard says a unified command was set up to oversee the coordinated response.

Authorities were seen taping off a ship.

The Charleston County Sheriff's Office, Hazmat and EMS crews were also on-scene.

Workers say they were told to leave the terminal at around 9 p.m.

Boaters say they were also escorted off the water due to the situation.