The Dead Sea is called the Salt Sea in the Bible (Gen. 14:3; Num. 34:3,12). The four kings of the east “joined forces in the Valley of Siddim (that is, the Salt Sea)” to fight against the five kings of the local region (Genesis 14:3 ESV).
There is an extraordinary evaporation in the sea. After evaporation, the remaining water contains about 25% of solid substances with chloride of sodium (common salt) contributing 7%. It has a bitter and nauseous taste, due to the chloride of magnesium. The chloride of calcium makes it smooth and oily to the touch.
Josephus knew the Dead Sea as Lake Asphaltites in Roman times (Ant. 1.174; 15:168).