5 Largest Refineries in the US

3. Marathon Petroleum Corp, Texas

Barrels per Calender Day: 593,000

Company: Marathon Petroleum Co LP

Site: Galveston Bay

The Galveston Bay Refinery, also known as Marathon Texas City Refinery, operates within the Texas City Industrial Complex on Galveston Bay. With a capacity of 593,000 barrels per day, it ranked among the largest refineries in Texas and the United States in 2008 and was the eighth largest globally by 2018. Established in 1931 as Republic Oil refinery, it merged with Marathon’s other Texas City refinery in 2018. However, in 2021, it gained notoriety as the top emitter of benzene, a carcinogen, into the US environment among all refineries, highlighting major environmental concerns.