President Donald Trump extended a Jones Act waiver for 90 days, allowing foreign-flagged ships to transport oil and other goods between U.S. ports, a White House official said Friday. The extension preserves the case-by-case approval process introduced in August, after the administration issued a blanket waiver in March, one month after the U.S. launched the war on Iran. It is the longest waiver in the history of the shipping law and is intended to expand shipping options, reduce transport delays and ease higher gas, diesel and fertilizer prices. Since the waiver began in March, an additional 90 million barrels of petroleum, primarily refined products, have moved between U.S. ports, including 27 million barrels of gasoline, 26 million barrels of crude oil and 6 million barrels of renewable fuels. The more than 100-year-old Jones Act requires cargo moving between U.S. ports to use ships built in the United States, owned by U.S. companies and crewed by American workers, and domestic shipbuilding supporters have historically opposed lengthy waivers.