Investigation reveals cause of Flint Hills oil spill in Corpus Christi Bay

Flint Hills Resources on Monday released the details of an investigation by a third-party consultant that determined the cause of a 14,000-gallon oil spill into Nueces and Corpus Christi bays on Christmas Eve four months ago.

A summary of the investigation, obtained by the Caller-Times, provides the clearest picture of the conditions preceding the incident, which drew condemnation from environmental advocates in Corpus Christi at the time and in the months following.

While city officials said the size of the spill did not warrant limitations to beach access, swimming or fishing, the incident and cleanup did force a temporary closure of the Corpus Christi Ship Channel. The Koch Industries-owned company initially estimated the spill to be 90 barrels, or 3,800 gallons, of light crude, but later upped its estimation to 335 barrels, or 14,000 gallons.

The report states the spill at the company's Ingleside terminal was the result of three factors: the company's omission to weatherize a certain pipe to protect from below-freezing temperatures, failure to empty a decommissioned pipe and having the shutoff value left open — meaning the pipe could not keep the water in and oil out.

The leak originated from a 3-inch "sump line," a pipe designed to transport liquids in the sump, such as rainwater, from the dock to the terminal tanks. This pipe, which Flint Hills Resources decommissioned in June 2022, was also used to transfer crude oil.

Due to subfreezing temperatures, water left in the pipe froze and expanded, fracturing the pipe. When the pipe failed, the liquid in the line drained out and allowed crude oil backflow and discharge from the sump line, releasing about 335 barrels of oil.

"We didn't properly freeze-protect all those lines. Our weatherization program failed to identify that line that needed to be weatherized or weatherproofed," Andy Saenz, a Flint Hills Resources spokesperson, told the Caller-Times Monday.

The company performed a freeze protection checklist ahead of the freeze event, but the check did not address the possibility of freezing within the sump line on Dock 5. The company has since updated its checklist to include inspections of low-flow and no-flow piping, such as the sump line on Dock 5, Saenz said.

Flint Hills Resources hired a third-party consultant to conduct the investigation. Saenz declined to provide the name of the company, saying company officials "wish to remain anonymous." Such a request is typical in the industry, he said.

Oversight by the U.S. Coast Guard and the Texas General Land Office remained ongoing this week, said James Duenes, the land office's regional manager in Corpus Christi. Once the cleanup efforts officially conclude, the land office will conduct an investigation and possibly assess penalties to Flint Hills Resources.

"We're basically in monitor mode," Duenes said. "We do meet weekly to discuss if anything's been picked up. … There's nothing of any major quantities we've picked up in a long time."

The light crude, which may resemble yellow “popcorn” or appear to be a small pebble of paraffin or wax, was found at North Beach, Corpus Christi Marina, Indian Point, Nueces Bay, the Rookery Island, a dredge material placement area and University Beach near Texas A&M University-Corpus Christi.

Small quantities have continued washing out from jetty and breakwater rocks near North Beach and University Beach, Saenz said, so cleanup crews have continued combing the area.

The land office and Texas Parks and Wildlife are evaluating deceased wildlife collected after the spill. Earlier this year, a U.S. Coast Guard spokesperson said 13 birds died and one turtle was treated due to exposure to crude oil.

After the incident, Flint Hills Resources drained, air-gapped and disconnected the leaking sump line from the piping used to transfer crude oil to the terminal tanks, according to a company news release on Monday.

The company is reviewing terminal operations to identify and address similar risks.

"This has forced us to look from the top to the bottom, top down," Saenz said. "We're looking at our weatherization and our weatherproofing for that entire plant. … We don't have a lot of experience with super cold weather here in Corpus, but we're having to learn really quickly."

The company is in the process of installing an array of air monitors and specialized surveillance equipment around the perimeter of the terminal and dock area. This effort will increase monitoring and potentially expedite response if there is another spill, Saenz said.

"No spills are acceptable. We obviously regret this happened, but if it's going to happen, (you must) respond appropriately and learn the lessons of your deficiencies," Saenz said. "That's what we've done."

The number to report any material or oil sheens will remain open. That number is 361-396-2831.

Editor's note: This story was changed after its initial publication to include information from the investigation summery and statements from Flint Hills Resources and Texas General Land Office.

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