California is excited over its rich oil and gas underground but the state is debating whether large scale of "fracking" is allowed.

California's Monterey Shale, which runs from Los Angeles to San Francisco, is thought to contain more oil than North Dakota's Bakken and Texas's Eagle Ford, both having created thousands of jobs and boosted U.S. oil production to the highest rate in over a decade.

The Monterey Shale is thought to hold over 400 billion barrels of oil -- nearly half the conventional oil in all of Saudi Arabia. The United States consumes about 19 million barrels of oil a day, according to the Cambridge Energy Research Associates.

Oil companies have developed a way to explore the rich oil and gas with hydraulic fracturing, also called "fracking." Supporters stressed that if large-scale "fracking" is allowed, the shale boom in California would add to the 600,000 jobs newly created nationwide over the last few years.

However, the hydraulic fracturing technology needed to exploit shale oil and gas has raised numerous environmental concerns.

Opponents say the practice, which involves pumping water and toxic chemicals into the ground to fracture rock, freeing the oil and natural gas trapped inside to be pumped to the surface, would consume large amount of water and cause underground water contamination. Deep groundwater almost entirely supplies residents and agriculture in many places in the state.

Reports said oil wells can use up to 1.46 million gallons of water a week and take up to eight barrels of water to produce a single barrel of oil. The water used in fracking then becomes a toxic soup the industry is still trying to find a way to safely dispose.

"Two of our state's most significant natural resources are water and oil. We had better make sure that obtaining one doesn't harm the other, and that our policies are developed based on real science and observation," said California State Senator Lois Wolk.

Unlocking the Monterey Shale could also endanger California's pledge to cut carbon emissions to 1990 levels by 2020.

Environmentalists say that if the oil were extracted and burned, the resulting greenhouse gas emissions would be the equivalent of delaying the state's climate goals by 80 years.

Activists have launched a campaign to stop "fracking" and that has prompted California legislators to debate whether to allow "fracking" and how to regulate it.