VLO Valero Energy Corporation

Valero Energy Corp. (VLO) reported Monday a disruption to operations and flaring of gas at its refinery in Port Arthur, Texas.

On the Texas Commission on Environmental Quality's website Monday, the company said personnel responded to an incident that began Friday when "a process unit upset resulted in excess emissions."

Representatives at Valero on Monday said that the disruption of operations took place at a sulfur recovery unit. The company had no further comment.

It wasn't clear whether fuel output at the 310,000-barrel-a-day refinery was affected or if operations have returned to normal.

The TCEQ filing said the excessive gas emissions that began around noon Friday had ended by Friday evening.

Write to Dan Molinski at Dan.Molinski@wsj.com

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