Record prices for diesel fuel are starting to hit Americans hard, and they're even weighing on stock prices.

The surge in diesel is hitting the profits of farmers and trucking companies, and causing severe sticker shock to consumers who use oil for heating. Trucking giant J.B. Hunt Transport Services said late Tuesday that soaring diesel and other costs would reduce third quarter profits by 5% to 10% from second quarter levels.

"We have seen some of the most radical and abnormal swings in fuel prices that we've ever seen," said CFO Brad Delco at an investment conference. Its shares were down 13% on Wednesday.

Farmers are seeing double-digit price hikes for diesel they use in tractors and combines just as harvest season hits.

The wars in Iran and Ukraine have sent diesel to its highest prices ever. The pain is escalating fast. At the pump, diesel hit a record $6.31 per gallon on Wednesday, according to AAA. That's up 37 cents from last week and 86 cents from last month.

A year ago, diesel was selling for $3.70 a gallon.

Patrick De Haan, head of petroleum analysis at GasBuddy, thinks several states could start seeing $7 diesel soon.

Heating oil, which is chemically similar to diesel fuel, is also getting much more expensive. The average household that uses heating oil is likely to spend about $2,520 this winter, up from $1,749 last winter, according to Mark Wolfe, executive director of the National Energy Assistance Directors Association, whose members administer heating assistance programs.

Diesel's surge has been spurred by a basic supply-demand mismatch. The war in Iran has reduced total shipments of crude oil and fuel from the Middle East. On top of that, Ukraine has been attacking Russian refineries, knocking out millions of barrels of daily fuel production. Russia restricted exports to make sure its own population has enough fuel. That left the rest of the world in a severe deficit.

The U.S. has ramped up diesel exports to cover some of the gap. American refiners shipped 1.61 million barrels per day in the most recent week, up from an average of 1.25 million barrels last year. But U.S. refineries are now running at nearly full capacity, so they won't be able to ramp up much more. U.S. diesel inventories are also depleted, sitting about 13% below last year's levels.

Some analysts have begun to discuss the possibility of a U.S. export ban, which would boost U.S. supplies and presumably lower prices here.

"I think the odds of a diesel export ban announcement before midterms is high," wrote Liz Thomas, head market strategist at SoFi, in a post on X on Tuesday.

Senate Majority Leader John Thune (R., S.D.), said this week he's open to discussing a ban. While the U.S. has banned crude oil exports in the past, it hasn't resorted to diesel bans before.

Oil producers have dissuaded policymakers from doing so, arguing it will distort global markets and eventually lead producers to curb supply-causing prices to rise.