He said the two deputies involved had been placed on administrative leave and he had launched an internal investigation. Due to unsafe conditions and rising waters, additional search and rescue teams are arriving to assist in the recovery of the vehicle.
Horry County Sheriff Phillip Thompson stated in a Friday news release, "Tonight's incident is a tragedy".
Marion county coroner Jerry Richardson has confirmed that two people drowned on the Little Pee Dee river.
Richardson provided the patients' names but not their spellings.
The Horry County Sheriff's Office transport van was still in the water as of about 8:45 p.m. Tuesday, WPDE reported.
It had gotten dark, and responders decided it wasn't safe to try to retrieve the women's bodies from the van Tuesday night. They were headed to facilities in Darlington and Lancaster.
Richardson said the incident happened on Pee Dee Island Road off U.S. Highway 76 outside of Nichols.
"The two deputies attempted to extricate the persons being transported", the news release said.
Two deputies tried to help the victims, but the floodwater rapidly rose and the deputies couldn't open the doors, according to the sheriff's office. The women remained chained in the van.
Rescue teams were able to save the deputies from the van's roof, but they could not pull the vehicle from the water because it was too risky, according to the release. "It's come up 2 feet (0.6 metres) since just last night".
Police scanner audio captured by CNN affiliate WMBF indicates the floodwater carried the van through a bridge guardrail near the Little Pee Dee Lodge on the Nichols side of the river. "When we get the order, we transport them". "The van is submerged, and they can not get their inmates out", an unidentified person says. High-water rescue teams rescued the deputies from on top of the van. "The two inmates are in the back of the van - are still in the van - and they're talking, and they're working on getting them out now".
Crews did not recover the bodies of Green and Newton on Tuesday night.
The incident is under investigation by the State Law Enforcement Division. This incident is being investigated by the State Law Enforcement Division (SLED).
The Transportation Department advised northbound motorists to take a wide detour around the area by using I-85 from Georgia through South Carolina's Upstate and on to Charlotte.