"natural hydrocarbon" refers to a type of substance found in the Earth that is made up of hydrogen and carbon atoms. It is naturally occurring and can be found in various forms such as gas, oil, or coal. Full definition
It's a salty brine, mildly radioactive, and laced not just with toxic chemicals but with natural hydrocarbons and heavy metals like barium and benzene, which are known carcinogens even in minute quantities.» (sourcewatch.org)
Most natural hydrocarbons are present in crude oil, the starting component of gasoline. (cheapcarinsurance.net)
Of particular concern were compounds called adamantanes, a natural hydrocarbon found in gas that can be used to fingerprint its origin, and 2 - BE, listed as a common fracturing fluid in the EPA's 2004 research report on hydraulic fracturing. (scientificamerican.com)