While the topic of hydraulic fracturing still remains in the spotlight, another unconventional method of extracting oil and natural gas from deep underground deposits has been quietly developing away from the general public interest.

The technology, called dry fracking, is very similar to hydraulic fracturing, but it does not require water. Instead, underground rock formations are cracked open by highly pressurized gas. Supporters of dry fracking say it is highly suitable for states like California, if regulators allow oil and gas companies to apply the method in oil and gas production. The state's shortage of water severely restricts the options for hydraulic fracturing and this may be an argument in favor of approving dry fracking, according to Minneapolis-based independent news website Mint Press.

California is estimated to hold approximately 15 billion barrels of oil in the Monterey shale, a formation that covers the area from northern California to Los Angeles. This means that the state could potentially produce more oil than North Dakota does from its Bakken shale. However, the fact that hydraulic fracturing requires as much as 4 million gallons of water per well means that it is scarcely applicable in California, where agriculture is a major industry and water management is vital.

On the one hand, dry fracking eliminates the water use issue, but on the other, it raises another set of concerns, Mint Press said. The huge amounts of gas used for the extraction of oil and natural gas mean that operations would be far more hazardous and even small mistakes could result in deadly explosions, explained Patricia Lerman, member of local advocacy group Aromas Cares For Our Environment.

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The San Francisco-based Center for Biological Diversity has also criticized the technology, stating that it has not been subject to extensive scientific research and it could be too risky to embrace it without even knowing what the potential implications for the state's environment, wildlife and communities could be.

According to Central Coast News, a Fox affiliate station, dry fracking is being implemented by at least two fracking companies operating in Texas — another state that has water-supply issues but relies heavily on hydraulic fracturing.

Calgary-based company Gasfrac Energy Services Inc., which also has an office in Houston, Texas, is one of these operators. The company's website claims that dry fracking is a safe and reliable method for production of fuel. It adds that the technology uses its patented Liquid Petroleum Gas gel, which contains no water.

dry fracking is highly productive and eliminates the need to use water in fracking operations, Gasfrac's website explains. While the technology has its own risks, different from those associated with hydraulic fracturing, safety is a top priority for the company. Gasfrac has developed protocols and safety features and its dry fracking operations have a high safety record in oilfield operation, the company's website pointed out.