# Diesel hits record highs as Iran war squeezes supply > The fuel that powers trucking, farming and heating is at all-time prices with no relief in sight. - Title: Diesel hits record highs as Iran war squeezes supply - Summary: The fuel that powers trucking, farming and heating is at all-time prices with no relief in sight. Diesel prices have jumped 78% since the U.S. war with Iran… - Keywords: diesel fuel, iran war, oil refining, trucking, us agriculture, us economy, strait of hormuz, refinery capacity, heating oil, freight transportation, supply chain, inflation - Source: The Conversation — https://theconversation.com/iran-war-pushes-diesel-the-economys-lifeblood-to-record-high-prices-with-no-relief-on-the-horizon-292049 - Author: Jamie Webster - Read time: 2 min - Topics: diesel fuel, iran war, oil refining, trucking, us agriculture, us economy, strait of hormuz, refinery capacity, heating oil, freight transportation, supply chain, inflation ## Diesel hits record high U.S. diesel prices reached $6.28 a gallon on September 14, 2026, breaking all-time records. Prices have jumped 78% since the Iran war began in late February. > Diesel fuel prices in the U.S. continue to break all-time records, hitting $6.28 a gallon as a national average on Sept. 14, 2026 ## Three factors driving the crisis Environmental regulations on refineries and Russia's Ukraine war created long-term pressure. The U.S. war with Iran closed the Strait of Hormuz for six months, pushing the situation into crisis. ## Clean air rules cut refining capacity Starting in 2006, federal regulations required refiners to produce low-sulfur diesel to reduce air pollution. Compliance cost billions and reduced energy content per gallon. ## Refineries closing, not opening Only one new refinery opened in 50 years. Two shut down in 2025, and more than a dozen converted to renewable diesel, cutting their output by at least half. ## Refineries running at maximum Remaining refineries are operating at nearly 98% capacity, the highest level since 2018. Yet diesel output is still lower than 2025. ## Diesel stockpiles at 75-year low Distillate inventories fell to 103 million barrels by late August, the lowest level for that date since 1951. Exports hit record highs as global markets sought supplies. > Distillate inventories held by refiners, distributors and retailers fell to about 103 million barrels by late August, the lowest for that point in the calendar since 1951. ## Russia and Middle East cut supplies Russia banned diesel exports on July 9, 2026 for its military and extended the ban through year-end. Middle Eastern refiners scaled back production due to Iran war disruptions. ## Refiners profiting from shortage Diesel profit margins, called crack spreads, surpassed $100 per barrel for the first time ever in late August. Refinery companies are charging record prices while demand far outpaces supply. ## Farmers hit hardest by costs Higher diesel prices added $1.4 billion to U.S. crop planting costs in 2026, a 63% increase. Illinois, Iowa and Minnesota were hit hardest. ## Heating oil crisis looming Heating oil, chemically similar to diesel, is a key fuel in the Northeast. Inventories are projected to fall below 100 million barrels in September and stay there through 2027. Heating oil prices are already up 30% or more. ## No quick fix even if war ends With refineries at maximum capacity and stockpiles depleted, even a sudden end to the Iran war won't bring significant price relief anytime soon. Any production interruption would worsen the shortage. > With falling stockpiles, even a sudden end to the Iran war is unlikely to yield significantly lower prices anytime soon. ## Key takeaway Diesel prices have jumped 78% since the U.S. war with Iran began, driven by lost refining capacity and global supply disruptions that will keep costs high through 2027.