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 whether 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 have 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 existing 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 U.S. 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 toxins 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 some 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 the practice does not pollute the environment in a way that would endanger human health. Oil companies must obtain permits for wastewater and storm water discharges from production platforms that "ensure all fluids used in the drilling and production process will not adversely impact water quality," the statement said.