In the Epic of Gilgamesh, bitumen was used to make the flood survivor’s boat watertight.
In the flood narrative of Tablet XI, Utnapishtim is instructed to build a boat and coat it with bitumen. Bitumen is a naturally occurring petroleum-based substance that was used in the ancient Near East as a waterproofing material, sealant, and adhesive.
The detail reflects practical boat-building knowledge in Mesopotamia, where reed boats and wooden structures needed protection from water. It also differs from the wording of the Genesis account, which tells Noah to coat the Ark with “pitch” but does not use the same literary context or character names.
Bitumen is therefore the specific material associated with Utnapishtim’s boat in the Epic of Gilgamesh. Beeswax, clay, and olive oil had ancient uses, but they are not the waterproofing material named in this flood episode.