Oil falls a fifth day and Brent slips under $100 as Saudi pipeline restarts, but diesel sets another record at $6.53

Crude oil fell for a fifth straight session on Tuesday after reports that Saudi Arabia is restarting its East-West pipeline, the route that lets Saudi crude reach the Red Sea without passing through the Strait of Hormuz. Brent was down 1.8% at $98.56 a barrel at 7:15 a.m. ET and U.S. West Texas Intermediate was down 2.3% at $93.60, CNBC reported. OilPrice.com said Brent had dropped below $100 for the first time in a week. Our live data had Brent still under $100 just before 10 a.m.; see the crude oil chart.

What is new on the pipeline

The Saudis shut the pipeline after a drone attack launched from Iraq on September 10. Riyadh is running tests and could restart it this week, a person familiar with the matter told Bloomberg News, according to CNBC. Reuters sources said it was already pumping at a low rate and exports could resume from the Red Sea port of Yanbu later Tuesday. Yahoo Finance, citing Reuters, said the line normally carries about 4 million barrels a day and that a security source put full restoration weeks away.

Diplomacy added to the drop. A senior Iranian official told Japan's Kyodo News that Iran could reopen the Strait of Hormuz within seven days if the U.S. eases its blockade of Iranian ports, which we covered in this morning's brief. CNBC said it could not independently verify that report.

Diesel is still going the other way

At the pump, diesel set a new record. AAA's national average was $6.5276 a gallon on Tuesday, up from $6.5107 on Monday, which was itself a record. Regular gasoline slipped slightly to $4.4750 from $4.4786, according to AAA.

The government's weekly survey, released Monday, shows where it hurts most. The Energy Information Administration put on-highway diesel at $6.529 for the week of September 21, up 24.4 cents in a week and $2.78 from a year ago. The Midwest jumped 43 cents in one week to $6.680, and New England rose 31.5 cents to $6.517. California was highest at $8.246.

Why falling crude helps diesel less

The headline read is that cheaper oil means cheaper fuel. For diesel, that is only partly true. In EIA's breakdown of the May 2026 retail price, crude oil made up 42% of a gallon of diesel, compared with 52% for gasoline. Refining was 25% of diesel's price, versus 22% for gasoline, and distribution and marketing were 23%, versus 15%.

In other words, a smaller slice of the diesel price moves with crude. Diesel's premium sits in refining margins and distribution, and those do not fall just because Brent does. Heating oil futures, the market's closest proxy for wholesale diesel, were down 1.32% at about $4.83 a gallon on OilPrice.com's price board Tuesday morning, a smaller percentage drop than crude.

That matters for anyone who buys diesel by the tankload: trucking and freight firms, farms heading into harvest, construction crews and delivery fleets. Carriers that set fuel surcharges off the EIA weekly price, a method EIA itself explains on its diesel page, typically bill this week off Monday's $6.529 reading, even if crude keeps falling. Relief, if it comes, will likely show up first in gasoline.

What traders are watching

How fast Yanbu loadings actually resume, and whether U.S.-Iran contacts at the UN General Assembly this week produce anything concrete. Treasury Secretary Scott Bessent told CNBC that all Iranian airlines will be shut down from Wednesday, a reminder that pressure on Tehran is still rising alongside the talk of talks.

Sources: CNBC; OilPrice.com; Yahoo Finance; AAA; EIA; Chronicle market data. Oil prices move quickly. This is market information, not investment advice.