Every year, Garrett Marrero orders thousands of pounds of malted barley and hops from the mainland to his business, Maui Brewing. Then, some of the beer he makes is sent by ship back to continental ports.

That round trip is getting more expensive. Mr. Marrero has already heard from a freighter that he’ll have to pay an increased fuel surcharge for shipments, and he’s thinking about how to soften the blow to his business. Eventually, he said, the price increases will “have to get passed along, or items will have to get reworked.”

It is no secret that fuel costs are soaring. The four-week U.S.-Israeli war with Iran, with its disruption of energy exports from the Persian Gulf, has led to a spike in oil prices that’s passing through to other products. For American consumers, the most apparent reminder of this is in the gasoline prices billboarded across the country.

A less immediate, though arguably more pernicious, threat to the economy is the cost of diesel — which has climbed faster than regular gasoline. That could lead to inflation across a wide range of goods, as businesses like Mr. Marrero’s are forced to contend with the added expense of producing and shipping everyday products.

“The cost of everything goes up — that’s a disconnect that I think a lot of consumers don’t necessarily understand,” Mr. Marrero said.

Diesel “powers a lot of basic industries,” said Vidya Mani, a visiting associate professor at Cornell University’s business school whose research focuses on supply chains. “Mining industries, chemical factories, clothing factories — a lot of those things come from diesel.”