Valero’s Texas City refinery released a plume of toxic gas early Sunday morning after an electrical panel malfunctioned, but the failure was unrelated to larger electrical outages that plagued the refinery three years ago.
Texas City’s emergency manager, Derek Duckett, said Valero representatives told him that they traced the problem to a faulty wire in a panel in the refinery’s sulfur recovery unit that caused a blown fuse. Valero spokesman Bill Day said the malfunction was isolated to an internal control panel that upset the sulfur recovery unit. He said the cause remains under investigation, but he declined to provide more information.
The plant did not experience any widespread power failures like it did in 2011, when a drop in voltage on the area’s electrical grid forced shutdowns at four of Texas City’s major refineries, resulting in flaring and the emissions of toxic gas for several days.
Texas-New Mexico Power, the area’s electrical provider, blamed the 2011 outages on salt and other debris that accumulated on power equipment during that year’s widespread drought. The company launched an extensive clean-up, power-washing insulators and other equipment to dislodge residue that can cause lines to short-circuit.
The company spent more than $2 million to clear the system of contamination that normally would’ve been rinsed away during by rain, including using helicopters and contract crews to wash more than 200 miles of high-voltage lines and 12 substations in the Galveston County system, spokesman Eric Paul in a statement.
“Since 2011, we have continued protocols to inspect our system and to watch for potential trouble before it strikes, particularly when rain has been scarce,” Paul said. “While we know outages are always possible on any power system, we take seriously our responsibility to maintain the highest reliability system for our customers in the Gulf Coast.”
When Valero’s electrical panel malfunctioned Sunday, the Texas-New Mexico Power grid was functioning normally, he said.
“Any incident on Sunday was unrelated to our systems,” Paul said.
Between 1:30 a.m. and 6 a.m., the refinery released an estimated 654 pounds of sulfur dioxide, a toxic gas that fossil fuels like coal and oil emit when they burn, according documents Valero filed with the Texas Commission on Environmental Quality. Sulfur dioxide has a pungent, choking smell that can cause respiratory problems, particularly for those with asthma.
Duckett issued a shelter-in-place order for thousands of residents living near the plant for more than three hours after he saw the plume of white vapor leave the refinery fence line. The emergency management office received one report from a resident complaining of headache and blurred vision.
“I ordered it out of an abundance of caution,” he said. “Better safe than sorry.”
Valero stopped the release by routing emissions to a control device, according to Texas Commission on Environmental Quality reports. The 245,000-barrel-per-day refinery has been operating normally since, Day said.