The U.S. Coast Guard has given the all-clear to reopen a terminal at the Port of Charleston in South Carolina, lifting a lockdown that was imposed Wednesday night after a threat of a “dirty bomb” on a container ship. The original source of the report—that four containers aboard the Maersk Memphis ship in the Wando Terminal were a “potential threat”—has been detained and is under questioning, officials said. All crew members were declared safe and on shore soon after the threat was issued. The 300-foot Maersk Memphis arrived in South Carolina from New York at about 7:30 p.m, according to Reuters. Just 30 minutes later, authorities were made aware of the possible threat and evacuated the terminal, the Coast Guard reported.