The original sauce used in the state was traditional vinegar and pepper used along the coastal plains by Scottish settlers. next sauce came back to the 1730s when the then British colony of S.C. recruited many German families and they introduced a mustard-based sauce to the mix.
Next came the light tomato sauce often referred to as "Carolina Red." This was the result of tomato ketchup becoming popular as a condiment around 1900. This sauce is essentially ketchup mixed with traditional vinegar and pepper sauce.
Now there is a heavier tomato sauce with variations which has gone on to become popular all across the U.S., but its origins are in the South.
'Cueing All the Way. --RoadDog