The driver, Wanda Rhoad, 56, and front-seat passenger, Kenneth Dixon, 49, both of Beech Island, died in the wreck, Aiken County Coroner Tim Carlton said.
A passenger in the back seat was admitted to Georgia Regents Medical Center. His condition was not available Friday night.
Rhoad was driving a Chevrolet truck northbound on Storm Branch Road at high speed when she lost control of the vehicle, Carlton said.
Alcohol containers were found in the truck, he said.
The accident occurred shortly after 6 p.m., according to the South Carolina Highway Patrol.
Toxicology tests were pending on Rhoad. Dixon was not wearing a seat belt, Carlton said.