AAA says the national average for diesel reached an unprecedented $5.98 per gallon on September 10, a new high for a fuel whose effects stretch well beyond filling stations. The increase is likely to reach people who never purchase diesel directly, showing up instead in the cost of everyday items and in higher home-heating expenses. More broadly, diesel is a key fuel for trucks and ships, and Grist described how rising diesel costs can feed into the prices of essentials including groceries and lumber. Compared with late February, when the United States and Israel went to war with Iran, AAA figures show diesel prices are about $2.31 higher. Grist also noted that the last major high point came in 2022, when Russia’s invasion of Ukraine helped send diesel to $5.82 per gallon. David Ortega at Michigan State University, explained how these increases typically move through the economy.