India, Sept. 13 -- A fuel-price warning is now showing up in an unusual place: the numbers on California gas pumps. Several stations have reportedly pushed diesel prices to $9.999 per gallon, a figure so high that their digital displays cannot show another cent. The extraordinary prices come as US diesel reaches record levels, oil supplies remain under pressure, and the continuing war with Iran disrupts energy flows through the Strait of Hormuz.

GasBuddy petroleum analyst Patrick De Haan said the company's data showed five California stations reaching the $9.999-per-gallon limit. He did not identify the individual stations or cities in his initial report, but the figures underline the severity of the diesel-price surge.

Recent reports h...