On October 7, 2019, the average California regular retail gasoline price surpassed $4 per gallon (gal) for only the second time since 2014, according to the U.S. Energy Information Administration’s (EIA) Gasoline and Diesel Fuel Update. The last time prices reached this level was in May 2019, which was a result of planned and unplanned refinery outages in California. California’s petroleum markets are isolated from the rest of the United States because of its lack of petroleum infrastructure connections to the rest of the country, so unplanned refinery outages in the state can have larger price impacts than in other areas of the country. In addition, California requires a different gasoline specification than the rest of the country, further narrowing supply options. The spike in crude oil prices following the September 14 attacks in Saudi Arabia on crude oil infrastructure led to a small, short-lived gasoline price increase across the United States, followed by several unplanned refinery outages in California. The refinery outages further raised gasoline prices in the state even though average U.S. gasoline prices declined.