Petroleum - Encyc

Petrooleum, also known as crude oil, is a black liquid found underground. It can be refined into useful products such as gasoline, diesel fuel, heating oil ?, lubricating oil ?, plastic, and grease ?.

Petroleum is a non-renewable resource. The discovery and rate of development of new reserves is currently keeping pace with demand, but this is expected to end sometime in the future as current reserves dwindle.