Petroleum products are materials derived from crude oil (petroleum) as it is processed in oil refineries. Unlike petrochemicals, which are a collection of well-defined usually pure chemical compounds, petroleum products are complex mixtures. The majority of petroleum is converted to petroleum products, which includes several classes of fuels.
According to the composition of the crude oil and depending on the demands of the market, refineries can produce different shares of petroleum products. The largest share of oil products is used as "energy carriers", i.e. various grades of fuel oil and gasoline. These fuels include or can be blended to give gasoline, jet fuel, diesel fuel, heating oil, and heavier fuel oils. Heavier (less volatile) fractions can also be used to produce asphalt, tar, paraffin wax, lubricating and other heavy oils. Refineries also produce other chemicals, some of which are used in chemical processes to produce plastics and other useful materials. Since petroleum often contains a few percent sulfur-containing molecules, elemental sulfur is also often produced as a petroleum product. Carbon, in the form of petroleum coke, and hydrogen may also be produced as petroleum products. The hydrogen produced is often used as an intermediate product for other oil refinery processes such as hydrocracking and hydrodesulfurization.
Oil refineries will blend various feedstocks, mix appropriate additives, provide short-term storage, and prepare for bulk loading to trucks, barges, product ships, and railcars.
Over 6,000 items are made from petroleum waste by-products, including: fertilizer, flooring (floor covering), perfume, insecticide, petroleum jelly, soap, vitamins and some essential amino acids. Out of all petroleum waste by-products, some are hazardous to health like toluene: a clear, colorless liquid with a distinctive smell.
A serious health concern is that toluene may have an effect on your nervous system (brain and nerves). Nervous system effects can be temporary, such as headaches, dizziness, or unconsciousness. However, effects such as incoordination, cognitive impairment, and vision and hearing loss may become permanent with repeated exposure, especially at high levels associated with intentional solvent abuse. High levels of toluene exposure during pregnancy, such as those associated with solvent abuse, may lead to developmental effects, such as retardation of mental abilities and growth in children. Other health effects of potential concern may include immune, kidney, liver, and reproductive effects.