(1) Benzene is a colorless and highly flammable liquid hydrocarbon derived from petroleum .

(2) Eocene formations are important source or reservoir rocks for petroleum or gas in several parts of the world.

(3) Products produced from petroleum , such as mineral oils, are classified as petrochemical pollutants.

(4) Crude oil, also known as petroleum , is the world's most actively traded commodity.

(5) Liquid paraffin is a mixture of liquid hydrocarbons obtained from petroleum .