A group of California lawmakers has asked the federal government to investigate offshore hydraulic fracturing along the California coast. New leases and drilling practices have been banned by the California State Lands Commission since 1969, when the Santa Barbara oil spill occurred in the Santa Barbara Channel in Southern California.

The spill was the largest in US waters at the time, and is now ranked third after the Deepwater Horizon and Exxon Valdez oil spills.

Since the late 1990s, fracking has occurred at least 12 times in the Santa Barbara Channel, the Associated Press reports. Earlier this year, regulators approved a new project, according to federal documents recently released to the AP through the Freedom of Information Act (FOIA).

The news came as a shock to the California Coastal Commission, who told the AP that, until recently, it had no idea that offshore fracking was even occurring. The drilling has reportedly occurred in federal waters, three miles off the coast, which means that oversight is the responsibility of agencies within the Interior Department. However, state coastal regulators should be involved if an offshore project affects water quality or marine life.

Naturally, the oil and gas industry asserts that their drilling processes are safe and effective. And unlike fracking on land, offshore drilling is less common and receives less attention. The offshore process involves pumping a mixture of salt water, sand, and toxic chemicals beneath the seabed in order to cause fissures in the underground rock.

Offshore fracking operations are smaller than onshore operations; however, there is concern that new ocean fracking projects are being approved without any new environmental impact analysis. And the AP found that fracking fluids are exempt from the US’s clean water laws by federal regulators, allowing companies to “flush treated discharges into the sea without a separate environmental review.”

“We are in the dark. It is very distressing,” state Sen. Hannah-Beth Jackson (D-Santa Barbara) told the AP.

The Interior Department has said it received the lawmakers’ letter and is reviewing it. Jackson and other state legislators also petitioned the California Coastal Commission to further investigate past drilling permits and future applications.

According to Bureau of Safety and Environmental Enforcement (BSEE) documents obtained through an FOIA by Truthout, federal regulators approved an application by a Ventura, California-based company, Dcor, LLC, earlier this year. The company received the green light to use fracking technology in a sandstone well 1,500 feet from a seismic fault in the outer continental shelf off the coast of California.

According to the report, regulators conducted a “geohazard” review before approving the project because the area is seismically active. Dcor is California’s largest offshore drilling company, operating 11 of the 24 rigs off California’s coast. Internal BSEE documents obtained by Truthout said that, according to Dcor, if their offshore fracking project is successful, the company will pursue more offshore projects.

Alisha is a writer and researcher with Ring of Fire. Follow her on Twitter @childoftheearth.