Some people calling 911 from cellphones Thursday morning received a busy signal, but by mid-afternoon the issue was cleared.
Other calls were routed to nearby call centers or came in on the Charleston center’s backup line, according to Charleston County 911 Deputy Director Allyson Burrell.
Berkeley, Dorchester and Charleston counties all reported having issues.
"Some customers in some Southeastern markets making landline to wireless, wireless to landline and 911 phone calls may have experienced interruptions while trying to make voice calls today," said Verizon spokeswoman Kate Jay.
The problem was with an AT&T trunking connection that connects calls, she said. The issue was resolved about eight hours after it was discovered.
The problem also stretched into parts of North Carolina and Florida, officials said.
The issue mainly affected callers whose carriers are Verizon and T-Mobile, according to Burrell. Both companies contacted the Charleston County Consolidated 911 Center early Thursday to alert them of the problem.
While the issue was inconvenient, it did not cause any major problems, Burrell said.
"I haven’t seen anything significant occur because of the issues," she said. "We are still continuing to process the calls even though they may be coming in a little bit differently than they ordinarily would."