BENICIA — The vast oil refinery in Benicia faces an uncertain future after its owner alerted state energy officials that plans were in the works for an array of options for the plant, including a possible closure.

Valero Energy Corp. notified the state Energy Commission that the company was considering numerous possibilities for the oil refinery, including a “current intent to idle, restructure, or cease refining operations at Valero’s Benicia Refinery,” Valero stated.

A decision would be made by the end of April 2026, Valero Energy told the state entity.

The company warned that the strategy review might extend well beyond the Benicia oil refinery.

“Valero continues to evaluate strategic alternatives for its remaining operations in California,” the energy giant reported the state commission.

The company also owns and operates an oil refinery in a Los Angeles neighborhood known as Wilmington.

The strategic evaluation — and the potential results of the review — are expected to be costly.

“In connection with the evaluation of strategic alternatives for Valero’s operations in California, a combined pre-tax impairment charge of $1.1 billion was recorded for the Benicia and Wilmington refineries,” Valero stated on Wednesday.

Publicly held companies often take impairment charges for assets they intend to write off or jettison. It wasn’t immediately clear what might occur regarding this particular California refinery situation.

Valero said it’s possible the ultimate decisions could have major effects on the Bay Area and Los Angeles.

“We understand the impact that this may have on our employees, business partners, and community, and will continue to work with them through this period,” said Valero Chief Executive Officer Lane Riggs.