Regulators in California have told oil companies and drillers to stop operating 12 wells within 500 feet of underground water supplies out of concern for public health.

The order from the Division of Oil, Gas and Geothermal Resources affected several companies, including Chevron, drilling for oil in Kern County using injection wells.

Officials said they had not discovered any contamination of aquifers in the drilling

areas, but were merely taking precautions.

“As we’ve said before, the protection of California’s groundwater resources — as well as public health — is paramount, particularly in this time of extreme drought,” Steven Bohlen, head of oil, gas and geothermal resources for the California Department of Conservation, said in a release (pdf). “Halting injection into these wells is a significant step toward that goal.”

The state is conducting a “systematic statewide review” of injection wells, according to Bloomberg, which also reported that “some well injections were taking place in zones that hadn’t been approved by the U.S. Environmental Protection Agency, triggering the evaluation of all 50,000 injection wells.”

The injection wells, used for decades to push oil and gas out of the ground, are different from hydraulic fracturing wells that have produced worries of polluting water supplies and causing earthquakes in some states.

-Noel Brinkerhoff

To Learn More:

Chevron, Linn Told to Halt California Wells on Water Concern (by Michael B. Marois and Lynn Doan, Bloomberg)

California Orders Oil Companies To Stop Drilling Near Drinking Water Supplies (by Ari Phillips, ThinkProgress)

Feds Say Alleged Lapse in Drilling Inspections Is Just Horrible Bookkeeping (by Ken Broder, AllGov California)