Records: Gas pressure for Coolidge pipeline explosion was below maximum federal regulations

Published: Sep. 16, 2022 at 8:57 AM MST|Updated: Sep. 16, 2022 at 8:35 PM MST
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COOLIDGE, AZ (3TV/CBS 5) -- The National Transportation Safety Board has released a 57-item docket with more than 1,200 pages of information into its investigation of the gas line explosion that happened in August 2021.

How it started

Coolidge police got a call just before 5:30 a.m. on Sunday, Aug. 21, 2021. about a fire in a rural part of town near the Hohokam canal, near Randolph Road. Officers arrived about two minutes later and noticed that fire was shooting out of the ground, forming a V-shape.

Investigators say a blast wave from the explosion traveled northwest and hit a farmhouse on Vail Road. Soon afterward, Kinder Morgan, the gas line operator, noticed a pressure decrease in the control center monitors.

Around the same time, the control center received a fire report from a nearby power plant. In addition, new documents released by the NTSB revealed that dirt from the explosion rained down on Union Pacific railroad workers nearly a mile away.

Crews had to manually close two valves -- one upstream and one downstream. While it took an hour to isolate the downstream, they had difficulty closing the upstream valve. As a result, it took crews about two-and-a-half hours to isolate the upstream valve, allowing firefighters to extinguish the fire that had flames burning an estimated 150 feet into the air.

Police said two victims died as a result of the explosion. They were identified as Luis Alvarez and his 14-year-old daughter, Valeria. Their mother, Rosalina Alvarez, sustained severe burns to about half her body. The Alverez family was the same family attacked by two inmates who escaped from a Florence prison in January 2021.

What investigators found

An initial NTSB report found that the line was installed in 1986 and used to transport crude oil. It later underwent two months of water pressure testing before it was converted for natural gas use. Kinder Morgan purchased the line in 2012. “Natural gas has certain safety features to it that are totally different in dealing with the combustibility of it and compressibility,” says Don Deaver, mechanical engineer, and law witness expert. “They have to shut the pipeline down, get rid of the natural gas and fill it up with water to take the pressure test. Often times companies do as little as they can to get by with the minimum,”

Data analysis showed that the gas pressure before the rupture was 863 psig, well under the 944 psig value allowed under federal regulations. Investigators are still looking into how the pipeline failed and are actively looking at inspection reports, construction records, and the polyethylene coating used. “It had to have some kind of cracks in it or flaws or damage to have caused it to initiate this rupture but it did not have the fracture resistance to stop it in its tracks,” says Deaver.

Kinder Morgan’s response

In December, Reuters reported that Kinder Morgan had placed the damaged part of the line entirely out of service after several months as it took steps to improve safety operations. Those steps include improving its data analysis systems and artificial intelligence technologies.

According to the outlet, flows declined from 0.8 billion cubic feet per day to 0.65 billion cubic feet. For reference, one billion cubic feet is enough natural gas for 5 million homes daily.

In its response to the NTSB, the company detailed that it replaced the ruptured pipe with a new one and reduced the operating pressure of the line from Ehrenberg, Arizona, to McCamey, Texas, by 20 percent. In addition, four leaks were found at compressor sites on above-ground equipment. Three leaks have since been repaired, with a fourth repair pending a scheduled shutdown of its Casa Grande station. Additional testing of the line is also in the works.

The NTSB stresses that “no conclusions about how or why the rupture occurred should be drawn from the information within the docket.” A final report by the NTSB is still set to be released sometime in the future.

Friday afternoon, Kinder Morgan sent Arizona’s Family the below statement.

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