The first use of hydraulic fracturing was in 1947. The modern fracturing technique, called 'horizontal slickwater fracturing', was first used in 1998. It made the extraction of shale gas economical. The energy from the injection of a highly pressurized fluid creates new channels in the rock, which increases the extraction rates and recovery of hydrocarbons.
Proponents of hydraulic fracturing point to the economic benefits from the vast amounts of previously out of reach hydrocarbons. Opponents point to potential environmental effects, such as contamination of ground water, risks to air quality, the migration of gases and hydraulic fracturing chemicals to the surface, surface contamination from spills and flowback and the health effects of these. For these reasons hydraulic fracturing has come under scrutiny, with some countries suspending or banning it.
- Charlez, Philippe A. 1997. Rock mechanics: petroleum applications. Paris: Editions Technip, p. 239
- Trembath A. 2012. US Government role in shale gas fracking history: an overview and response to our critics. 
- Golden rules for a golden age of energy. International Energy Agency. 
- Brown, Valerie J. 2007. Industry issues: putting the heat on gas. Environmental Health Perspectives. 115 (2): A76. 
- France to keep fracking ban to protect environment, Sarkozy says. BloombergBusiness.