The incident occurred Friday morning at Rumuekpe under Emohua Local Government Area.
The casualty figure is speculated to be more than a dozen, though no official confirmation as at press time.
Available information has it that the explosion, which also consumed vehicles, emanated from the tapping point of a pipeline.
It was gathered that a driver had loaded one of the buses at the location with crude oil packaged in bags.
Preparing to move the petroleum product away from the scene, he started the vehicle engine, which triggered a blast.
The man and others nearby are among the fatalities.
