Chevron Well at Center of Major Oil Spill in Kern County Oil Field

A Chevron oil well has leaked nearly 800,000 gallons of crude petroleum and water in Kern County over the last two months, prompting state regulators to hit the San Ramon-based energy company with a notice of violation and an order to halt some oil extraction work in the area around the spill.

The leak, which the company says has stopped, began on May 10. Crews reported a mixture of oil and water seeping from a well site in the sprawling oil fields near the town of McKittrick and about 35 miles west of Bakersfield.

Chevron and other firms operate thousands of oil wells in the area, many using a technique in which steam is injected more than 1,000 feet into the ground to heat up crude petroleum and make it easier to extract.

The initial leak, which state officials call a "surface expression," lasted 10 hours, said Mary Fricke, a spokeswoman for the Department of Fish and Wildlife's Office of Spill Prevention and Response, which is monitoring the incident.

Oil began seeping again on June 8 and June 23, according to Don Drysdale, a spokesman for the state's Division of Oil, Gas, and Geothermal Resources. The discharge was contained in a dry creekbed adjacent to a steam injection well.

Chevron's reports to the Governor's Office of Emergency Services show the spill has grown from relatively modest amounts to a major incident, with material flowing from three different points.

On June 11, the company, in a brief incident report to the Governor's Office of Emergency Services, said that a total of about 6,000 gallons of liquid had spilled by that date. On Thursday, the amount stood at nearly 795,000 gallons -- enough oil and water to submerge a football field to a depth of 2½  feet.

The spilled material consists of about one-third oil and two-thirds water, according to Chevron's entries in the OES hazardous spill database. That would mean nearly 265,000 gallons of oil have been discharged.

For comparison, 140,000 gallons of crude spilled in the 2015 Plains All American Pipeline oil spill in Refugio State Beach in Santa Barbara County in 2015.

Currently, the oil and water has been contained to an area that's 250 feet long and 20 feet wide, according to DOGGR. The agency added that Chevron was using vacuum trucks to suck up the spilled material.

State regulators say they plan to sample the leak to get a more precise estimate on how much of the material is petroleum and find out what caused the leak.

A Chevron executive told state officials earlier this month that a well at the center of the spill was damaged.

"There are multiple damage spots in the well," Adam Young, a company engineer, wrote in en email to DOGGR officials. It's unclear if the damage was sustained before or during the spill.

California's underground injection regulations require operators like Chevron to prevent "surface expressions." In addition to issuing a notice of violation in the incident, DOGGR ordered the company to stop oil extraction work within a 600-foot radius of the spill.

The agency says Chevron stopped steam injection into wells 1,000 feet around the incident to alleviate pressure in the area.

DOGGR's Drysdale said about 20 steam injection wells in the area have been taken offline and nine wells that were idle have returned to operation — also to alleviate pressure.

Chevron has kept government agencies in the loop on the spill and is working with them to investigate it, according to company spokeswoman Veronica Flores-Paniagua.

"Fluid from the seep is contained. There has been no impact to waterways and wildlife," Flores-Paniagua said in an email.

Small surface expressions are common in oil fields, according to state officials. Drysdale said the current incident is unusual because three separate vents have allowed fluid to come to the surface.

Hollin Kretzmann, an Oakland-based attorney for the Center for Biological Diversity, said the incident illustrates the hazards that go along with crude oil extraction.

"It underscores the danger of this industry," Kretzmann said. "Whether it's pipelines, whether it's wells, whether it's refineries,  every stage of the process has some sort of risk. Unfortunately in this case, it's resulted in a large-scale disastrous accident."

Kretzmann said Chevron's spill has the potential of hurting local wildlife and future drinking water supplies.

State officials say no one has been injured, there's no risk to the public and no water that's used for drinking or farming is affected by the spill.

"The incident is not near any aquifers that would be suitable for beneficial use," said W. Dale Harvey, an engineer with the Central Valley Regional Water Quality Control Board.

Glenn Fankhauser, Kern County's agricultural commissioner, said the nearest farm is 6 miles north of the oil field.