Oct. 8—The U.S. Environmental Protection Agency has issued an ultimatum to California oil and water agencies that have fallen years behind schedule in their efforts to bring the state's oilfield injection program into compliance with the federal Safe Drinking Water Act.

A Sept. 16 letter from the director of the EPA's water division, Tomás Torres, gave the California Natural Resources Agency and the State Water Resources Control Board 30 days to update their proposed plan for completing final paperwork for exempting certain underground aquifers from the SDWA by no later than Sept. 30, 2022.

If the state is unable to meet the federal government's deadlines, Torres wrote, then the EPA will consider limiting or ending the state's authority over injection work, including activities such as carbon capture and sequestration, a technology proposed in Kern for fighting climate change.

Other possible "punitive actions" he listed include withholding grant money, unspecified enforcement against the state and federal orders that California oil producers quit injecting wastewater into aquifers that have not been properly exempted from the SDWA.

The state's failure to keep up with the federally approved schedule jeopardizes California oil production. If the EPA follows through on its threat to halt injections into certain aquifers, then some oil producers will likely have nowhere else to put the salty wastewater that comes up from the ground with oil — "produced water," it's called. In that case, they may have to limit or cease production, at least until the EPA assumes oversight and completes the approval process.

The situation frustrates local oil producers that have filed extensive paperwork for aquifer exemptions only to have the state hold onto their applications for years at a time without forwarding it to the federal government.

In one instance cited by Torres, the state apparently completed its review of an exemption package for an aquifer in Ventura County two years ago — but according to the letter, the paperwork still has not been sent to the EPA.

"The letter recognizes that CalGEM (the state's primary oil regulatory agency, the California Geologic Energy Management Division) and the water board have had ample time to process these applications," Rock Zierman, CEO of the California Independent Petroleum Association trade group, said by email. "Now it's just a matter of will."

The state water board and CalGEM, which state officials said the letter should have been addressed to instead of the Natural Resources Agency, defended themselves in a statement emailed Friday afternoon. It said the agencies continue to work together on a path to bringing California's injection control program into full compliance with the federal drinking water act.

"This is a technical, complex geotechnical process involving multiple agencies that requires thorough subsurface analysis to determine whether an aquifer should be exempted because it is naturally impaired by metals, hydrocarbons or other containments that make the water non-potable," the statement said. "CalGEM and (the water board) continue regular engagement with U.S. EPA on progress to complete the aquifer exemptions and remain committed to protecting public health and the state's natural resources."

Underground injection is considered the safest and most environmentally responsible way to dispose of produced water. The problem is that oil producers have been injecting the fluid into aquifers that, though approved for that use by the state, remain federally classified as potential sources of drinking water off limits to produced water injections.

The federal government put California on notice in 2012 that state regulators had wrongly approved a number of aquifers for wastewater injection work. Initially the state was supposed to meet a 2017 deadline for making necessary changes to its oversight of what's known as its Class II Underground Injection Control program.

When the problem came to light, and dozens of Kern County injection wells had to be taken offline, California regulators traced the problem to a miscommunication between the state and federal governments in the early 1980s. That's when the EPA gave California primacy over Class II UIC regulation in the state.

Since then, oil producers have worked to prove the aquifers they inject produced water into are suitable for such deposits. In some cases, they have claimed wastewater is simply being returned into the aquifer it came from.

Torres' letter noted there has been "significant progress" toward returning California to SWDA compliance, including the processing of 21 of 30 expected exemption proposals. But he added that "there are still too many wells continuing to inject into these unauthorized aquifers."

"It is particularly troubling," he continued, "that the state continues to miss critical timelines to achieve compliance, especially in this time of drought and diminished water supplies across the state."