California expands list of water contaminating oil field operations

California has expanded the list of oilfields operations which could be contaminating water sources during below ground oil well injection.

Water authorities in the state have also accepted that oilfield operations have been polluting the federally protected underground aquifers.

Initial review of injection wells related to oil production has been submitted to the US Environmental Protection Agency (US EPA).

The expedited review was supervised by the California Department of Conservation (DOC) and State Water Resources Control Board (State Water Board). It focused on 532 wells which had been injecting the wastewater into federally protected groundwater.

State Water Board Groundwater Monitoring Section chief John Borkovich said: "Our review was based upon whether the injection wells pose an immediate risk to water supply wells.

"The Division has shut in the injection wells where the risk of contamination is considered highest. The Water Boards are requiring the operators to supply detailed water quality data and information to assess if groundwater resources have been contaminated."

23 central California oilfield injection wells, which found to be affecting nearby public water wells, have been shut down, out of them 22 of those are in Kern County and one in Tulare County.

An additional 30 more sites have been marked as high-priority potential risks to nearby water wells, according to letter sent by the state regulators to the US EPA.