Readers were surprised to learn from my Sunday story that oil companies are allowed to send their drilling muds and boring waste into unlined pits.
They do it with a waiver that was granted several years ago. The Central Valley Regional Water Quality Control Board does not view the muds and waste as a hazardous discharge.
But the waiver will expire next month. Environmental groups are pressing the state to end the waiver and require more protection for the underground water table.
My Sunday story was not about the muds or boring wastes. It was about a separate and controversial practice of hydraulic fracturing, or fracking, which includes the use of chemicals to help free up oil trapped in shale formations.
Fracking fluids were illegally discharged into two of those unlined pits, called sumps. Regional water authorities found the chemicals in concentrations above safe thresholds.
The regional board is now investigating the sumps of several dozen oil companies in the San Joaquin Valley.
The concern is that the contamination might wind up in drinking water systems and irrigation water.
The contaminated sumps are both near Shafter in Kern County, which produces most of the oil in the Valley and in the state. The sumps and wells are owned by Vintage Production, a subsidiary of Occidental Petroleum Corp.
To be abundantly clear: The drilling muds and boring waste are not part of fracking, which takes place after the well is drilled. The muds and boring waste have long been considered a low threat.
The Center for Biological Diversity says the muds and wastes themselves contain many kinds of chemicals to help reduce friction and make the drilling more efficient. Some chemicals are related to gas and diesel.
The group, representing many activists, says the time has come to regulate it.
Fresno fracking opponents demonstrated last weekend as part of “Global Frackdown2,” a worldwide effort to oppose injecting chemical-laden water into the ground to open up oil-bearing rocks.
The opposition is stirred by fears of drinking water contamination and overburdening existing water supply.
The demonstration was led by Fresnans Against Fracking. The group, like many other opposition organizations, wants to see a moratorium on fracking — a shorthand name for hydraulic fracturing.
The local group is asking for the Fresno City Council and the Fresno County Board of Supervisors to pass an ordinance to enforce a moratorium.
In the San Joaquin Valley, this is no small issue.
Along the western edge of the Valley, there are deep shale rock formations that hold an estimated 15 billion barrels of recoverable oil.
That is an attractive prospect to local leaders. Many thousands of jobs could be created, and there would be a tax bonanza.
Many public officials are courting the idea, but environmentalists have been hammering it. They say the practice needs to be thoroughly studied first.
Last month, Gov. Jerry Brown signed Senate Bill 4, the first fracking law in California. It requires oil companies to obtain permits for fracking as well as acidizing, the use of hydrofluoric acid and other chemicals to dissolve shale rock.
It also requires notification of neighbors, public disclosure of the chemicals used, as well as groundwater and air quality monitoring and an independent scientific study.
Neither side of the debate likes the law. The oil industry opposed the bill, saying it goes to far in regulating their work. Environmentalists generally opposed it as well, saying it is not nearly protective enough.
In Fresno, Gary Lasky, president of Fresnans Against Fracking, says there is not enough known yet about the impacts to the water and air. He said the groundwater and air should be protected before fracking is allowed.