I invite you to follow the links in the above linked story, for more information like this:
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.
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 in general is safe and has "never been associated with any risk or harm to the environment" in over 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.