The state of California ordered that seven oil companies stop injecting “produced water,” or fracking waste water, into 11 sites in Kern County because they’re too close to wells used for drinking and irrigation water. On Friday, state oil regulators lifted the ban for two of the wells.

Oil producers have long injected fracking waste into aquifers that had been deemed by the state as having no potable water and are not protected from such practice. However, the maps delineating where waste aquifers are compared to useable water are often inaccurate. It appears now though that at least some waste is going into fresh water aquifers, according to ProPublica. No tainted water has been found, but testing and monitoring of the affected wells has been ordered. “We do not have any direct evidence any drinking water has been affected,” Steve Bohlen, the state oil and gas supervisor, told ProPublica. The affected wells are near Bakersfield, and about 100 water wells are located within a mile of the waste wells, according to the Bakersfield Californian.

Oil companies say they’re injecting the waste as they should. “This is somewhat shocking,” Dwayne Roach, president of Bakersfield’s Pace Diversified Corp., told the Californian. He said his operation is injecting wastewater back into the same zone, or depth, it came from, “so I’m not sure how that can be viewed as contaminating it.”

The order comes as agricultural producers in California’s Central Valley are forced to dig deeper and deeper wells in order to get the water to irrigate their crops during the current drought.

Some states hit by drought are treating and using water similar to that in wells California has deemed suitable for waste disposal, according to ProPublica, and California might have to consider doing the same if the drought continues.

“Our drinking water sources must be protected and preserved for the precious resources they are, not sacrificed as a garbage dump for the oil and gas industry,” Damon Nagami, a senior attorney with the Natural Resources Defense Council, told ProPublica.

A 2011 Environmental Protection Agency report said California’s oversight of injection wells was insufficient and urged that it be improved. The report charged that the geology around injection wells was not studied thoroughly enough to ensure that waste was not flowing into drinking water.

-Steve Straehley

To Learn More:

California Halts Injection of Fracking Waste, Warning it May Be Contaminating Aquifers (by Abrahm Lustgarten, Pro Publica)

State Poised To Shut Down 11 Local Oil Injection Wells (by John Cox, Bakersfield Californian)

State Allows Two Oil Field Injection Wells to Resume Operation (by John Cox, Bakersfield Californian)

Oklahoma Earthquakes Blamed on Disposal of Fracking Waste (by Noel Brinkerhoff, AllGov)

Colorado Halts Use of Injection Well for Fracking Waste because of Earthquakes (by Noel Brinkerhoff, AllGov)