In response to federal reviews that suggest that state regulators have allowed oil companies to contaminate protected aquifers, California oil/natural gas regulators have filed a plan with the U.S. Environmental Protection Agency (EPA) to correct regulatory deficiencies.

The focus of concern is injection wells, which have been part of the state’s oil/gas landscape for decades.

The California Department of Conservation, which includes the Division of Oil, Gas and Geothermal Resources (DOGGR), and the state Water Resources Control Board outlined the proposal to EPA in a 12-page letter. This follows the discovery last summer that some underground injection wells had been allowed to discharge into water wells that had not been exempted by from federal drinking water protections.

The state has held authority to regulate underground injection wells by the EPA since 1983. The injection wells are used to boost oil recovery and dispose of fluids produced in conjunction with oil and gas. Currently, state officials don’t think any hydraulic fracturing (fracking) was involved in any of the troubled wells.

Of concern are up to 2,500 injection wells that are alleged to have deposited fluids or waste into EPA-protected aquifers as part of an audit done by the federal agency several years ago. This resulted in an effort by state authorities to upgrade California’s underground injection control (UIC) program. Friday’s submittal to EPA outlines how the state intends to resolve the concerns.

While not denying that in some cases the state UIC has allowed wells in violation of the federal Safe Drinking Water Act, Steve Bohlen, state oil/gas supervisor, on Monday said that the wells in potential violation may number up to 140, but nowhere near the 2,500 figure that has been identified by the state’s critics and regional EPA officials.

Bohlen said California has “a significant problem” and it is dealing with it quickly, focusing on public health. “We’re working cooperatively with EPA and the state/regional water boards, stakeholders and legislators,” he said. “We have had a series of frank, in-depth discussions with industry, they understand the problem and are eager to work with us to resolve the problem.”

Western States Petroleum Association (WSPA) officials said the state is taking the situation very seriously and has laid out “an extensive plan” to address it. While WSPA said it has some concerns with the state’s plan to EPA, it noted that page 5 of the proposal stated “to date, the analytical data from the water supply wells that the State ordered to be tested have not shown any contamination of the water supply wells by oil and gas injection activities.”

“In places like the Los Angeles Basin, where we have good data, it is fairly evident that the impact from oil and gas is limited and public health has been secured in that environment,” Bohlen said during a hastily called conference call with news media Monday.

Late last year, EPA’s Region IX office in San Francisco requested “a more detailed plan” to address issues surrounding the state UIC. In the work plan, the state said that DOGGR and the water control board will work to put California in full compliance with the federal standards.

California concedes in the submittal to EPA that it must make “long-overdue revisions” to the UIC, including addressing “shortcomings” in its data management system, a DOGGR spokesperson said. “A process has been developed to determine the wells with the highest risks associated with injection, and the steps to be taken to bring injection well permits into compliance with the primacy agreement with the EPA,” California states in its work plan.

Currently, California has more than 50,000 oilfield injection wells operating, and about 75% of the state’s 575,000 b/d production is the result of enhanced oil recovery (EOR), which includes steam flood, cyclic steam, water flood and natural gas injection.

“The landscape is really quite complicated,” Bohlen said. “Of the 2,500 number for the injection wells, 2,021 are EOR wells, meaning they are producing oil, leaving some 532 water disposal wells, including 109 that are idle, and 87 active wells in 11 aquifers whose exemptions from the federal Clean Drinking Water Act we think may have been confused.”

There are left about 140 injection wells putting fluids into aquifers that would need to be treated for the water to be made drinkable, or “beneficial use” water. These water wells have not received formal exemption from the EPA standards.

State officials said they have been working with EPA and the state water board in reviewing underground injection throughout the state. Last summer, 11 injection wells deemed to be posing a threat to drinking water were shut down. “Any additional such wells likewise will be shut down,” said a DOGGR spokesperson.