The plant, which now has a capacity to process 560,500 barrels per day of oil, was built by Humble Oil and started production in 1920 with had a capacity of 10,000 bpd.

Initially employing 100 people, the refinery helped build up local communities that eventually formed the City of Baytown, and today employs 4,000.

The plant relies on a heavy supply of crude from Mexico, Saudi Arabia, Iraq and Kuwait. With Motiva's Port Arthur expansion shut to resolve pipe issues until next year, Baytown is the largest operating plant in the United States.