Initial reports find exploded pipeline showed signs of ‘misalignment’

A federal investigation into what caused an underground pipeline explosion in southeast Iowa Saturday morning states two sections of the pipeline showed signs of misalignment.

“At the point of failure, investigators observed a four-foot section of ejected pipe with visible external corrosion,” according to the Corrective Action Order issued by the federal Pipeline and Hazardous Materials Safety Administration, part of the U.S. Department of Transportation.

“The two sections of pipeline that remained in place in the crater showed visible signs of misalignment,” according to the order, which directs organizations to immediately fix violations, safety risks or environmental contamination.

The segment of the pipeline that exploded is part of “East Leg Loop Pipeline,” which is part of the 8,000-mile pipeline system owned and operated by Texas-based Enterprise Products Partners LP.

Per the report, the company “observed a pressure drop on the East Leg Loop” around 10:50 a.m. Feb. 14, which resulted in the explosion.

Enterprise has cut out the failed section of the pipeline and is transporting the pipe to an engineering and inspection company in Texas.

The company estimated about 2,000 barrels of liquefied petroleum gas were lost in the explosion.

The failed pipe appeared to be in a location previously excavated and inspected, the federal order stated. The portion of the pipeline that exploded was originally built in 1972, according to the order.

Download: PHMSA Corrective Action Order 42026005 - Enterprise Products.pdf

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The Enterprise pipeline transports natural gas liquids from a hub in Conway, Kan., to petrochemical plants and propane markets in the Upper Midwest. Natural gas liquids are different from the natural gas — which is mostly composed of methane — that many utilities transport. Natural gas liquids include ethane, propane, butane, isobutane and pentane, according to the U.S. Energy Information Administration.

DNR: No significant impact

Meanwhile, the Iowa Department of Natural Resources has determined the explosion and fire had no significant environmental impact.

Tammie Krausman, communications director for the Iowa DNR, said Wednesday that DNR employees were at the site Saturday in Washington County, near Brighton, and found the explosion had not impacted nearby water bodies, including the Skunk River, which had fires burning on both sides of its banks.

Krausman said DNR staff also determined the explosion and fire had no impact on the county’s air quality.

The explosion shot a huge fireball hundreds of feet into the air that could be seen for miles. No injuries were reported. The pipeline is part of the Mid-America Pipeline System, unrelated to the Mid-American Energy Company.

Melissa Myers, communications director for the Iowa Utilities Commission, said the state agency also sent investigators to the site Saturday but that the investigation will be spearheaded by the federal Pipeline and Hazardous Materials Safety Administration.

According to previous reporting by The Gazette, the pipeline that exploded over the weekend was one of nine segments of pipelines owned and operated by Enterprise in Iowa that did not have permits between 2002 and 2023, resulting in a $1.8 million penalty being assessed the company. The company appealed that fine, which has been upheld in court.

Olivia Cohen covers energy and environment for The Gazette and is a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues. She is also a contributing writer for the Ag and Water Desk, an independent journalism collaborative focusing on the Mississippi River Basin.

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Comments: olivia.cohen@thegazette.com