California Gov. Gavin Newsom is in a spat with a major oil company over who is to blame for the state’s high gas prices, with the Democratic governor’s office urging drivers not to fill up at Chevron stations over Memorial Day weekend.

“Pro tip: unbranded gas comes from the same refineries, storage tanks, and pipelines, and it meets the same state standards to keep your engine running clean,” Newsom’s office posted Thursday on X. “Big Oil is already making billions off Trump’s Iran War; don’t let them rip you off even more by overpaying for the brand name.”

Newsom’s office cited an analysis by a group within the state’s energy commission, which oversees the oil and gas industry, that found that Chevron averaged more than 60 to 80 cents per gallon above unbranded alternatives.

Memorial Day weekend is one of the busiest travel times of the year. The call-out by the governor’s office follows Chevron posting signs at California gas stations blaming the state’s climate policies for the high cost of gas. The average price of gas in California sat at $6.14 per gallon on Thursday, about $1.58 higher than the national average, according to the American Automobile Association. The state taxes consumers about 70 cents per gallon of gas, according to the state’s energy commission. That is the highest gas tax in the country.