"This requirement was added in response to recent concerns regarding the potential effects of discharges of fluids used for offshore hydraulic fracturing operations," the EPA said in its notice.
The oil industry has insisted that fracking, which has been around for decades, does not harm the environment.
While attention has been focused on fracking on land close to communities, little is known about the practice in the ocean, which uses far less fracking fluids.
Well permits and emails obtained through the Freedom of Information Act show fracking has quietly occurred off Southern California since the late 1990s with mixed success.
After the AP stories were published, the California Coastal Commission launched an investigation. A group of state lawmakers also called on the federal government to look into the practice.
The largest offshore frack was completed in January 2010 by Venoco Inc., which targeted the Monterey Shale, home to one of the nation's largest deposits of shale oil.
"It did not produce the results we expected," Venoco spokeswoman Lisa Rivas said in an email Thursday.
Rivas said the company does not have plans to frack in the future.
The new EPA rule applies only to new drilling jobs on nearly two dozen grandfathered-in platforms in federal waters off the Santa Barbara coast, site of a 1969 oil platform blowout that spilled more than 3 million gallons of crude oil, ruined miles of beaches and killed thousands of birds and other wildlife.
That spill led to a prohibition on new offshore platforms in federal waters off California, but companies used fracking and other techniques in an attempt to stimulate new production from old existing wells.
Separately, state oil regulators have drafted rules requiring companies to test groundwater and alert landowners before fracking or other well stimulation. Companies would also have to disclose the chemicals used and acquire permits before a job. Those rules go into full effect in 2015.
The California Independent Petroleum Association and Independent Oil Producers' Agency did not respond to messages for comment. The Western States Petroleum Association said none of its members use hydraulic fracturing technology in offshore federal waters.
Environmentalists said the new federal rule was a step in the right direction, but they still want the government to ban the practice altogether.
"The EPA's rule will provide some information about the toxic fracking chemicals dumped into our ocean, but it relies on oil companies to be honest and transparent in their self-reporting," said Miyoko Sakashita, senior attorney at the Center for Biological Diversity.
