Iran War Sends U.S. Diesel Prices Soaring, Bringing Food Costs Into Focus

The war with Iran is no longer being felt only on battlefields or in Gulf shipping lanes. In the United States, diesel has reached a record price, raising the cost of operating trucks, freight trains, ships, farm machinery and the refrigeration systems that support the food supply chain.

American Automobile Association data available on Sept. 5, 2026, put the national average diesel price at $5.8819 per gallon. The figure set another record after diesel reached about $5.85 per gallon on Sept. 4. A year earlier, the average stood at roughly $3.71. Before the U.S.-Israeli war against Iran began in late February, it was about $3.76.

That means the fuel underpinning the movement of goods in the United States rose by more than $2 per gallon in about six months. The latest developments added to the concern. Brent crude held near a six-week high after renewed U.S.-Iran attacks targeted vessels and tankers in the Gulf. Brent traded around $96 per barrel after approaching $98.

Tensions also grew after Iran said it would announce a new restricted zone in the Gulf and organize new shipping routes through the Strait of Hormuz, a narrow passage central to global energy trade. When ships reduce their voyages, wait for escorts, change routes or face attack risks, the cost of transporting each barrel rises.

Shipping data cited by Reuters showed commodity-ship traffic through Hormuz falling well below normal after military tensions escalated again. On one day in early September, only four commodity ships crossed the strait, compared with an average of about 13 per day during the previous 10 days. Goldman Sachs has estimated that oil could rise to around $120 per barrel if attacks on ships in the Middle East intensify and cause major disruptions to oil exports.