The extension continues the longest waiver in the shipping law’s history, but foreign vessels are not automatically cleared for every trip. Shippers must obtain approval for individual voyages and show that suitable U.S. vessels are unavailable, a restriction introduced in August after domestic maritime industry opposition to earlier blanket exemptions.

The 1920 Jones Act requires cargo moved between American ports to travel on ships that are U.S.-built, U.S.-owned and U.S.-crewed. Suspending the requirement expands the pool of vessels available. Phillips 66 was among the first companies to use the original waiver, sending roughly 300,000 barrels of Bakken crude from Texas to Monroe Energy’s Trainer refinery in Pennsylvania in April aboard the Malta-flagged HTM Warrior.

Government figures cited by Reuters show about 300 waivers were issued under blanket exemptions in March and May. Since the move to individual approvals in August, 48 have been granted. The White House says the added shipping flexibility could help contain gasoline, diesel and fertilizer prices, but earlier exemptions brought little relief at the pump.

AAA put the average U.S. gasoline price at $3.91 per gallon on Thursday, up from $2.98 before the Iran war began. Diesel averaged $6.10, compared with $3.76. Shipping represents only a small share of retail gasoline costs, and critics estimate that easing the Jones Act would save consumers only pennies per gallon. More than 50 Republican lawmakers urged Trump in June to restore the restrictions, citing maritime jobs and national security concerns. The latest extension leaves the individual-approval process in place.