LOS ANGELES (AP) – A group of state lawmakers has asked the federal government to investigate hydraulic fracturing off the California coast where new oil leases have been banned since a disastrous oil spill in 1969.

Fracking has occurred in the Santa Barbara Channel at least 12 times since the late 1990s, and regulators earlier this year approved a new project, according to a recent report by The Associated Press, which obtained well permits and internal emails through the Freedom of Information Act.

The extent of fracking in the Pacific causes “extreme concern,” state lawmakers led by Assemblyman Das Williams, D-Santa Barbara, said in the letter this week.

Unlike fracking on land, which has spurred efforts to prohibit or curtail the practice, fracking in federal waters is less common and has not received the same attention.

Offshore jobs, which are typically smaller than ones done onshore, involves the pumping of hundreds of thousands of gallons of salt water, sand and a mixture of chemicals beneath the seabed. Most of the efforts to date have yielded mixed success in increasing oil production.

Federal environmental regulators so far have exempted fracking fluids from the nation’s clean water laws, allowing companies to flush treated discharges into the sea without a separate environmental review, the AP found.

The California Coastal Commission said it had no idea until recently that ocean fracking was even happening and planned to ask oil companies in the future whether they intend to frack. Since the work occurs in federal waters, oversight falls to agencies in the Interior Department. But state coastal regulators have a say if an offshore project affects water quality or marine mammals.

The oil industry insists fracking is safe and does not harm the environment.

Despite the assurances, state lawmakers said they wanted greater scrutiny over the practice. Past fracks have occurred in the vast offshore oil fields of Southern California, site of the 1969 spill that released more than 3 million gallons of crude oil into the ocean, fouling beaches and killing birds and other wildlife.

“We are in the dark. It is very distressing,” said state Sen. Hannah-Beth Jackson, D-Santa Barbara, who was among the lawmakers who signed the letter addressed to the Interior Department and Environmental Protection Agency.

On Thursday, Jackson and other state legislators petitioned the coastal commission to take a closer look at past permits and future offshore applications.

The agency “takes its responsibility to protect coastal and marine resources very seriously, and staff is currently investigating this issue to assure that California’s coast is fully protected,” commission spokeswoman Sarah Christie said in a statement.

Interior Department spokeswoman Jessica Kershaw said the agency has received the earlier letter and was reviewing it. The EPA said it would also review the letter and reiterated that its current permitting process ensures that fluids used in oil drilling and production will not impact water quality.

State Assemblyman Mark Stone, D-Monterey Bay, said he favored greater regulation of offshore fracking.

Stone, a former coastal commissioner, said he’s less concerned about whether the federal government or state should take charge “so long as the end result is that offshore fracking has appropriate oversight and has rules in place to minimize environmental damage.”

Copyright 2013 The Associated Press.