Gas well being drilled outside Sacramento. (Lauren Sommer/KQED)
Gas well being drilled outside Sacramento. (Lauren Sommer/KQED)

The debate over hydraulic fracturing, or fracking, to extract oil and gas has largely focused on the chemicals injected underground and their potential impact on public health. Now environmental groups are turning their attention to the waste produced by simply drilling a well in the first place. Water regulators in the Central Valley, home to most of the state’s oil production, will consider the issue at a meeting Thursday.

Drilling mud is the slick concoction used to cool and lubricate a drill bit, and it’s used for all kinds of wells, not just oil and gas. After a well is drilled, the mud and other wastes from drilling the well are often stored aside in unlined pits near the drilling site.

Five years ago, the Central Valley Regional Water Board included drilling muds in a broad waiver that exempted drillers from having to report and monitor those muds, saying they posed little threat to water quality. Other exemptions included swimming pool discharge and water from air conditioners.

That waiver is now up for renewal, and environmentalists say when it comes to drilling muds, oil and gas companies should not get a free pass. Especially since the last time the Regional Water Quality Control Board looked at the health effects of drilling muds was back in 1981, before the fracking boom.

“The most obvious step is to take a time out and really update our understanding of drilling muds and the risk they pose, especially with the spread of new techniques like fracking,” said Hollin Kretzman, a staff attorney with the Center for Biological Diversity. Kretzman says the waste generated from oil wells could contain harmful chemicals and contaminate groundwater.

No one’s opposing a study, said Tupper Hull, of the Western States Petroleum Association. “We have no problem with that,” he said. “But imposing additional regulations that make drilling more costly, more time consuming, energy production more costly for consumers, without evidence of harm, just doesn’t make sense.”

But after reviewing comments from several environmental groups, the Water Board’s staff is recommending that regulators revoke the waiver for drilling wastes while they study potential health effects.

Meanwhile, proposed fracking regulations would require the State Water Quality Control Board to put together a regional groundwater monitoring program for areas where well stimulation, like fracking, takes place. But those rules are largely concerned with chemicals injected into the ground, not drilling muds or the waste from simply digging a well.


Sasha Khokha

Sasha Khokha is Central Valley Bureau Chief for KQED’s  statewide public radio program, The California Report. Based in Fresno, she covers a vast geographic beat, including the nation’s most productive farm belt, some of California’s poorest towns, and Yosemite and Sequoia/Kings Canyon National Parks. Whether trekking up a Sierra glacier with her microphone, interviewing farmworkers in Spanish, or explaining complicated air or water quality issues, Sasha translates rural California to the rest of the state. Sasha  is a graduate of the UC Berkeley Graduate School of Journalism and Brown University, and the mother of two young children. @KQEDSashaKhokha

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