State Attorney General Kamala Harris and the California Coastal Commission have filed a lawsuit challenging the federal government's finding that fracking off the state's coast is environmentally safe.
The suit filed Monday in federal court says the Department of Interior failed to take a "hard look" at the environmental effects of 22 offshore oil platforms that use techniques including acid and hydraulic fracturing, better known as fracking, to stimulate production.
Two environmental groups sued over the processes last year and reached a settlement in January with the federal government, which agreed to do a new environmental assessment.
The government returned in May with a report that found no significant environmental impact.
Monday's lawsuit challenges that assessment, and demands a more extensive evaluation.
A message left with a Department of Interior spokeswoman was not immediately returned.