Marathon Oil Corp. has brought its expanded Louisiana refinery up to full production, turning out nearly 20 million gallons of gasoline and other fuels a day, according to a report by BusinessWeek.

Following a $3.9 billion expansion, Houston-based Marathon is now processing about 436,000 barrels of oil per day at its New Orleans-area refinery and producing 19.5 million gallons of gasoline and other fuels daily. Previously, the refinery could handle 256,000 barrels of oil and turn out 12 million gallons of fuels daily.

BusinessWeek reports there hasn”t been a refinery built from the ground up in the United States in 33 years — and that was the original Garyville plant. The new units went into service in late 2009 and the retooled older portion returned to production late last month, making the refinery the fourth largest in the country, according to Marathon officials.

To read the full BusinessWeek report on this story, click here.