The number of flaring incidents in 2018 at Chevron’s Richmond refinery was at its highest level in 12 years, according to data the Bay Area Air Quality Management District released Monday at a board of directors committee meeting.

The refinery experienced nine flaring events last year, more than any other refinery in the Bay Area. That’s the highest number of such incidents since 2006, when the Chevron refinery experienced 21 flaring events.

The Tesoro refinery in Pacheco experienced five flaring incidents last year, Valero’s Benicia refinery conducted four, Shell in Martinez had three and Phillips 66 in Rodeo had two, according to the air district.

The jump, which started in the last eight months, is connected to the start up of a new hydrogen plant that recently began operating at the facility, according to John Gioia, who represents the area of the refinery on the Contra Costa County Board of Supervisors and sits on the air district’s board of directors.

“All the sudden we saw this spike,” Gioia said in an interview. “There are some issues related to the new hydrogen plant and how it is integrated with the existing refinery.”

Gioia said it will probably take several months for Chevron to make fixes at the plant to reduce future flaring operations.

“For those of us who live in Richmond, we may continue to see some additional flaring while these issues are resolved,” he said.

Air regulators and oil industry officials emphasize that flares are used as safety devices to reduce pressure inside refineries by burning off gases during facility malfunctions as well as start up and shutdown operations.

Chevron’s hydrogen plant is part of the refinery’s modernization project, approved by the Richmond City Council in 2014, that is aimed at helping the facility refine higher-sulfur crude oil.

Braden Reddall, a company spokesman, said late Monday that the refinery was flaring “due to startup activities at a processing unit.”

“The flaring does not pose any environmental or health risk to the community,” Reddall said in an email.

“We want to assure our neighbors that flares are highly regulated safety devices, designed to relieve pressure during the refining processes and help keep our equipment and plants operating safety,” he said, adding that the refinery continues to supply its customers.

But Reddall did not answer questions about the connection between the hydrogen plant and the refinery’s recent uptick in flaring incidents as well as what kind of fixes the company is putting in place.

Gioia said the refinery began using the hydrogen unit last fall.

In the first three months of 2019, there have been five malfunctions at Chevron, the most recent one on Sunday afternoon, according to Randy Sawyer, Contra Costa County’s chief environmental health and hazardous materials officer.

That incident sent black smoke into the air and lasted two-and-a-half hours, Sawyer said.

It came 11 days after the refinery suffered an outage that caused several processing units at the facility to shut down, prompting the facility to send gas through its flares.

The refinery also suffered outages on Feb. 2 and Jan. 17 and conducted a separate flaring operation on Feb. 24.

The air district is investigating most of those incidents, according to agency spokeswoman Kristine Roselius.

“We don’t think this is an acceptable situation,” said Jack Broadbent, chief executive officer of the air district, during Monday’s meeting before the district’s Stationary Source Committee.

Gioia said a significant portion of the gas coming from the refinery’s flares during the recent incidents has been pure hydrogen, which does not present the same health risk as other gases like sulfur dioxide and benzene, which tend to get released during other flaring operations.