Major cases of process incidents are often traced to Loss of containment of crude oil. Loss of containment of crude oil plays an important adverse role not only because it waste lands, destroys vegetation/environment, cause a disaster in the ecosystem, renders sources of water supply unfit for drinking for local occupants but also because when come in contact with fire source it potentially leads to fire accident/explosion with severity ranging from minor damages to fatalities. The Petroleum Industry Safety Acts hold the achievement of prevention of losses of containment as an all important primary aim/objective. A mathematical modeling is therefore essential in risk assessment and consequence evaluation. This paper presents a quantitative loss of containment model for risk assessment and consequence evaluation by hazard classification and ranking to enable possibility of prevention or mitigation of losses of containments and ascertain the extent of damage done.