SACRAMENTO -- State regulators told California's oil industry Wednesday that they have tripled their rate of approving certain underground injection operations considered key to Kern County petroleum production. But the change was not enough to satisfy an industry that has heavily criticized the state's oversight.

Representatives of the state Division of Oil, Gas and Geothermal Resources said at a quarterly gathering here that the agency had managed to raise its injection project approval rate from 12 percent in 2011 to 36 percent last year -- even amid a 10 percent surge in application volume.

Reviewing waste disposal injection applications now takes an average of about three months, assuming the operator's paperwork is complete, said Jerry Salera, director of DOGGR's underground injection control program. Historical comparisons were not available Wednesday.

Salera credited the approval rate increase to a risk-based approach that takes into account local conditions instead of treating all project applications the same. Another DOGGR official said a surge in hiring at the agency has also contributed to the improvement.

But a three-month turnaround is still not good enough, said Randy Adams, a former DOGGR supervisor in Kern County who represented Bakersfield's Independent Oil Producers Agency at Wednesday's meeting of the California Oil & Gas Workgroup.

"It's probably double the time it used to take a couple of years ago," Adams said.

DOGGR's chief deputy, Rob Habel, agreed that further improvement is necessary, but he emphasized that the division is still hiring people to review injection project applications.

State review of underground injection work became a highly contentious issue in 2010 and 2011, when the industry accused former DOGGR chief Elena Miller of dragging her feet when reviewing such projects.

The division countered at the time that such activity -- typically involving reinjection of toxic materials that come up during normal oil production -- presents a potential threat to groundwater. Miller further questioned whether the state has legal authority to regulate such work; the division has since affirmed that it does have the authority.

In November 2011 Gov. Jerry Brown ousted Miller and her boss at the Department of Conservation, Derek Chernow, amid pressure by Kern oil companies and politicians.

Right of access

Also Wednesday, DOGGR warned the industry that oil companies may face civil penalties if they deny division representatives access to their oil field operations.

Habel handed out copies of a letter the agency sent oil companies Monday reminding them of DOGGR's right of access. The letter states that the division has the right to inspect "oil and gas wells, tanks and other facilities," and that a violation could result in a fine of up to $25,000.

Habel said in an interview that the violations -- which he said include instances of companies denying the state access to certain data -- appear to reflect misunderstandings, not intentional confrontation.

"It's not the company," he said. "It's sometimes that staff is not trained yet."

The meeting represented by far DOGGR's biggest presence at a meeting of the workgroup in several years.

Under Miller, the division stopped attending the gatherings altogether, reflecting what some in the industry called evidence of the agency's uncommunicative turn. Meanwhile, other regulators, from regional water quality officials to U.S. Bureau of Land Management representatives, continued to attend the meetings that have been praised for fostering cooperation between government and industry.

On Wednesday, though, several DOGGR employees took turns introducing themselves and explaining what they do.

DOGGR chief Tim Kustic said the sizable state delegation was only natural given where the meeting was taking place.

"You're in Sacramento, so we wanted to give you a deep dive into the division," he said.