SAN FRANCISCO -- Companies prospecting for oil off California's coast have used hydraulic fracturing on at least a dozen occasions to force open cracks beneath the seabed, and now regulators are investigating if the practice should require a separate permit and be subject to stricter environmental review.
While debate has raged over fracking on land, prompting efforts to ban or severely restrict it, offshore fracking has occurred with little attention in sensitive coastal waters where, for decades, new oil leases have been prohibited.
Hundreds of pages of federal documents released by the government to The Associated Press and advocacy groups through the Freedom of Information Act show regulators have permitted fracking in the Pacific Ocean at least 12 times since the late 1990s and recently approved a new project.
The targets are the vast oil fields in the Santa Barbara Channel, site of a 1969 spill that spewed more than 3 million gallons of crude oil into the ocean, spoiled miles of beaches and killed thousands of birds and other wildlife. The disaster prompted a moratorium on new drill leases and inspired federal clean-water laws and the modern environmental movement.
Companies are doing the offshore fracking -- which involves pumping hundreds of thousands of gallons of salt water, sand and chemicals into undersea shale and sand formations -- to stimulate old wells into new oil production.
Federal regulators thus far have exempted the chemical fluids used in offshore fracking from the nation's clean-water laws, allowing companies to release fracking fluid into the sea without filing a separate environmental-impact report or statement looking at the possible effects. That exemption was affirmed this year by the Environmental Protection Agency, according to the internal emails reviewed by the AP.
Fracking fluids can comprise hundreds of chemicals -- some known and others that aren't, since they are protected as trade secrets. Some of these chemicals are toxic to fish larvae and crustaceans, bottom dwellers most at risk from drilling activities, according to government health-disclosure documents detailing some of the fluids used off California's shore.
Marine scientists, petroleum engineers and regulatory officials interviewed by the AP could point to no studies that have been performed on the effects of fracking fluids on the marine environment. Research regarding traditional offshore oil exploration has found that drilling fluids can cause reproductive harm to some marine creatures.
"This is a significant data gap, and we need to know what the impacts are before offshore fracking becomes widespread," said Samantha Joye, a marine scientist at the University of Georgia who studies the effects of oil spills in the ocean environment.
The EPA and the federal agency that oversees offshore drilling, the Bureau of Safety and Environmental Enforcement or BSEE, conduct routine inspections during fracking projects, but any spills or leaks are largely left to the oil companies to report.
In a statement to the AP, the EPA defended its oversight of offshore fracking, saying its system ensures that the practice does not pollute the environment in a way that would endanger human health. Oil companies must obtain permits for wastewater and stormwater discharges from production platforms that "ensure all fluids used in the drilling and production process will not adversely impact water quality," the statement said.
Oil companies also maintain that much of the fracking fluid is treated before being discharged into the sea. Tupper Hull, spokesman for the Western States Petroleum Association, said fracking is safe and has "never been associated with any risk or harm to the environment" in more than six decades in California.
California coastal regulators said they were unaware until recently that offshore fracking was even occurring, and are now asking oil companies proposing new offshore drilling projects if they will be fracking.
Because the area of concern is located more than three miles off the state's shoreline, federal regulators have jurisdiction over these offshore exploration efforts. However, the state can reject a permit in federal waters if the work endangers water quality.
"It wasn't on our radar before, and now it is," said Alison Dettmer, a deputy director at the California Coastal Commission.
Government documents, including permits and internal emails from the BSEE, reveal that fracking off California is more widespread than previously known. While new oil leases are banned, companies still can drill from 23 grandfathered-in platforms in water where endangered blue and humpback whales and other marine mammals often congregate.
In March, a privately held oil and gas company received permission from the agency to frack about 10 miles off the Ventura County coast. The job by DCOR LLC involves using the existing wellbore of an old well to drill a new well. Three "mini-fracks" will be done in an attempt to release oil locked within sand and rocks in the Upper Repetto formation.
A month before the application was approved, an official with the BSEE voiced concerns about the company's proposed frack and wanted to know if the operation would discharge chemicals into the ocean.
"We have an operator proposing to use 'hydraulic stimulation' (which has not been done very often here) and I'm trying to run through the list of potential concerns," Kenneth Seeley, the BSEE's regional environmental officer for the Pacific, wrote in a Feb. 12 email to colleagues. "The operator says their produced water is Superclean! but the way they responded to my questions kind of made me think this was worth following up on."
BSEE officials approved DCOR's application on March 7. The agency told the AP that DCOR's job would use far less fracking fluid than an onshore operation.