Reuters reports the explosion happened around 7:30 p.m. local time, causing a blaze that burned for nearly five hours, which sent large plumes of smoke into the air and shook homes miles away, prompting a temporary shelter-in-place order for nearby residents.
According to Jefferson County Sheriff Zena Stephens, the explosion may have been caused by an industrial heater.
Officials later confirmed the fire was extinguished by Tuesday, with no injuries reported.
The refinery — Valero’s largest in Texas and one of the largest on the Gulf Coast — employs roughly 770 workers and processes up to 435,000 barrels of oil per day (bpd).
The incident comes as heightened geopolitical uncertainty around the ongoing conflict with Iran continues and tanker traffic is still being disrupted through the Strait of Hormuz — a critical chokepoint for global oil shipments.