The San Francisco Bay Area has its first countywide fracking ban.
The San Jose Mercury News reports that Alameda County supervisors in Oakland approved the ban late Tuesday by a 5-0 vote.
Fracking is when oil companies inject water or chemicals underground at high pressure to force oil out of rock.
Oil companies and environmentalists disagree over whether the process endangers underground water supplies, among other problems. Gov. Jerry Brown has resisted environmentalists' call for a statewide ban on fracking. Opponents have succeeded in winning fracking bans in several counties, however.
The Mercury News says Alameda County has drilling by only one oil company currently, and that company already does not use fracking.