State shuts 33 wells injecting oil wastewater into aquifers

California regulators on Thursday closed 33 oil company wells that had injected wastewater into potentially drinkable aquifers protected by federal law.

The new closures bring to 56 the number of oil-field wastewater injection wells shut down by the state after officials realized they were pumping oil-tainted water into aquifers that potentially could be used for drinking or irrigation.

The division, part of California’s Department of Conservation, for years issued oil companies permits to inject their left-over water into aquifers that were supposed to be off-limits, protected by the federal Safe Drinking Water Act.

The problem, detailed in a Chronicle investigation earlier this year, raised fears of water contamination in a state struggling through a historic, four-year drought.

The division has identified 178 wells that were injecting into legally protected aquifers with relatively high water quality, defined as those with a maximum of 3,000 parts per million of total dissolved solids.

“Both regulators and producers are committed to protecting underground water supplies, and today’s announcement reinforces the seriousness of that commitment,” said Catherine Reheis-Boyd, president of the Western States Petroleum Association.

“California’s oil and natural gas producers are committed to operating their wells in a manner that continues to safeguard public water supplies,” she said.

Revelations that the division allowed injections into relatively fresh groundwater supplies touched off a political firestorm, triggered lawsuits, and led Bohlen to launch a reorganization of his staff.

Under regulations adopted this year, wells injecting into aquifers with water quality between 3,000 and 10,000 total dissolved solids must cease injections by Feb. 15, 2017, unless granted an exemption from the federal Environmental Protection Agency.