'Soot' in the Bible

Then the Lord said to Moses and Aaron, “Take handfuls of furnace soot, and Moses is to throw it toward heaven in the sight of Pharaoh.

The soot will become dust over the entire land of Egypt, and it will become boils erupting into sores on people and animals throughout the land of Egypt."

So they took furnace soot and stood before Pharaoh. Moses threw it toward heaven, and it became festering boils on man and beast.