Patrick De Haan, head of petroleum analysis at GasBuddy, told EuroHerald that a handful of California stations have displayed diesel prices of $9.999 per gallon, the highest figure the digital pumps can show. The price cap was recorded on a pump in the San Diego suburb of Serra Mesa on Wednesday, and the firm is checking whether similar displays appear elsewhere.
What triggered the record price?
GasBuddy's data show the state's average diesel price has risen to $7.91 per gallon, while the national average topped $6 for the first time ever. The analyst warned that the average could climb to $7 per gallon in the coming weeks.
"There are really no signs of any improvement," De Haan said.
He added that some stations may simply be out of diesel, using the $9.999 display as a warning sign when fuel runs dry temporarily. Nevertheless, several pumps are now charging well above $9 per gallon.
Why the surge matters for Europe and the world
The United States is the world's largest diesel consumer, and the price spike reverberates through global supply chains. Diesel powers trucking fleets, agricultural machinery and many industrial processes. With the harvest season beginning in September, higher fuel costs could squeeze European food exporters that rely on US freight services.
Internationally, the rise coincides with heightened tensions in the Middle East. OPEC reported that Saudi Arabia's oil output fell to its lowest level since 1990 after Yemeni Houthi attacks disrupted Red Sea shipments. The Strait of Hormuz, a key chokepoint for oil transport, has also seen renewed targeting of tankers.
Global benchmark crude rose almost 8 % on 10 September, reaching $109 a barrel, the highest level since May. While gasoline prices in the United States have hit a September record of $4.27 per gallon, diesel is now the more acute concern for consumers and businesses.
What could happen next?
De Haan warned that the $9.999 figure could become a realistic pricing option if supply constraints persist. He said further clarification is needed on whether stations can legally adjust software to display prices above $10 per gallon or switch to half-gallon pricing.
Industry analysts such as Susan Bell of Rystad Energy argue that higher pump prices may be the only way to force "demand destruction" and curb consumption, while oil forecaster Dan Pickering of Pickering Energy Partners says the market is already competing for a limited diesel supply with no new refineries in sight.
Unless geopolitical tensions ease and strategic reserves are replenished, the United States could see daily fuel-related costs rise from $700 million to over $1 billion compared with last year, with diesel described as the "troublesome child" of the energy market.
European policymakers will be watching the US market closely, as any sustained increase in diesel costs could feed into broader inflationary pressures across the continent, especially for sectors dependent on trans-Atlantic freight.