Hydrocarbons are compounds comprised exclusively of carbon and hydrogen. Hydrocarbons are commonly used for fuel (e.g. petrol, natural gas, fuel oil, diesel fuel, jet fuel, coal, kerosene, and propane etc). Hydrocarbons are also used to make things, including plastics and synthetic fabrics such as polyester.  Soils and sediments contaminated by hydrocarbons can have a significant impact on their microbiological, chemical, and physical properties.