According to Nakuru County Commandant Francis Kirathe, five of the victims died on the spot while the sixth died in hospital.
He said it was unclear what caused the fire that also left six other people in a critical condition.
Kirathe said the survivors who were rushed to Eldama Ravine District Hospital have severe burns. Two of them have been moved to the Rift Valley Hospital after developing complications.
He said the driver and the conductor in the lorry escaped with minor injuries after an accident. After they were taken to hospital, locals rushed to the scene and started scooping the fuel.
In January 2009, more than 100 people died after an oil tanker explosion at Sachangwan in Molo. The people had gone to the scene to scoop oil when one of them lit a cigarette that resulted in a huge blaze.
Few months after the Sachangwan tragedy – June 2009 – another oil tanker rolled and residents rushed to the scene to scoop oil and as a result four people died while over 50 others escaped with serious injuries.