Whether prices are up or down, Californians consistently pay more than people in other states, and California State Attorney General Kamala Harris wants to find out why.
Drivers are filling up for under $3 a gallon at many Southern California gas stations, but that wasn't the case last year. The group Consumer Watchdog said California oil refiners were manipulating supply and price and called on the state attorney general to investigate.
According to the Wall Street Journal, the AG's office has subpoenaed oil refiners, but a spokeswoman for Harris declined to comment on whether her office was investigating.
Consumer Watchdog said Californian's were paying about $1.50 more per gallon than the rest of the country at one point last year. California perennially has among the nation's highest prices for gasoline. On Thursday, the average for a gallon of regular was $2.90 compared with the national average of $2.29, according to the auto club AAA.
An explosion at the Exxon Mobil refinery in Torrance last February led to an outage, and prices spiked in California. Consumer Watchdog said Exxon Mobil could've used a ship to deliver gasoline.
The Western States Petroleum Association issued a statement saying they have found no evidence of violations.
The statement read in part: "Over the past several decades, numerous investigations and expert market analysis have found no evidence of illegal activities or violation of anti-trust laws…I expect the conclusion will be consistent with past findings: market factors are the primary driver of fuel costs in California."
Some drivers said they're not buying the explanations given for why Californians pay more – whether it's a refinery off line or the summer and winter blends required in California.
"There's a lot of people that 5 cents a gallon is, you know, a big deal because they're trying to buy groceries and what not, so I don't think there is any question that we get the short end of the stick," said Bob Schwartz of Tarzana.
Spokesmen for ExxonMobil and Tesoro also confirmed they received a subpoena, but none of the companies would discuss the matter further.
The Associated Press contributed to this report.