Light Cycle Oil (LCO) is a versatile intermediate product in oil refining, primarily originating from the Fluid Catalytic Cracking (FCC) unit. Due to its unique composition, its generally not used directly as a finished fuel but rather serves as a valuable feedstock for further processing.

LCO is a crucial "middle ground" product in a refinery: its too heavy for gasoline and too contaminated for direct diesel use. Its value lies in its potential to be transformed through further processing into high-demand products like clean diesel and valuable petrochemicals.