An investigation is ongoing into the Wednesday morning rupture and explosion on a segment of Tennessee Gas Pipeline (TGP) in southeastern Ohio, but girth weld failure is suspected. The same Line 200-4 pipeline experienced such a failure earlier this year, as did the similar Line 200-1 pipeline.

El Paso Corp.’s TGP entered into a consent agreement with the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration’s (PHMSA) Office of Pipeline safety following the two previous incidents, which occurred Feb. 11 and March 1. An order issued by PHMSA late Thursday specifies additional actions TGP must take on the affected line, a 27-mile segment of which has been shut in due to the latest rupture.

“A visual inspection by PHMSA and Tennessee Gas indicates that the pipeline failed at a girth weld,” PHMSA said in its Thursday order. “The apparent cause of the failure is unknown and the investigation is ongoing. Line 200-4 remains shutdown and isolated from the Albany Compressor Station (MLV 204-4) to MLV 206-4.”

No customers have been impacted by the shutdown of the line, Tennessee said (see Daily GPI, Nov. 17), That remained the case as of Friday morning although the pipeline had issued a force majeure as a precautionary measure. The rupture occurred on the 36-inch diameter line at about 8:45 a.m. EST near Glouster in Morgan County, OH.

The affected line is about 230 miles long and runs from Greenup Compressor Station in Greenup County, KY (MLV 200) to the Mercer Compressor Station in Mercer County, PA (MLV 219). The Line 200 system is composed of four parallel lines — Lines 200-1, 200-2, 200-3 and 200-4 — which are generally located within a common right-of-way.

In a March Notice of Proposed Safety Order PHMSA said the Feb. 10 failure on Line 200-4 in mainline valve section 214, about 2.5 miles southeast of Haverton, OH; and the March 1 failure on Line 200-1 in mainline valve section 209, about half a mile downstream of the pipeline’s Cambridge Compressor Station 209 “demonstrated the presence of integrity risks on those segments of Lines 200 1-4 running from Compressor Station 200 to Compressor Station 219, including what is known as the Pittsburg Spur.

The pipelines traverse “high-consequence areas,” according to PHMSA.

Besides the shut in of the affected segment, PHMSA ordered a pressure reduction of 20% along the affected line between MLV 200-4 to MLV 219-4. The order outlines other requirements for inspection, testing and analysis.

El Paso said it had received the order and is reviewing the details. “We have been working closely with PHMSA since the first reports of the failure and intend to fully comply with the terms of the Corrective Action Order [CAO],” El Paso said Friday. “As a prudent operator, we voluntarily reduced the pressure by 20% in most segments of the line (from Main Line Valve 204 and MLV 219) involved in the failure before the CAO was issued.

“Based on current scheduled quantities and requirements, there should not be an impact to scheduled volumes. If additional requirements become necessary during this outage and such requirements would impact scheduled volumes, Tennessee will communicate this information as soon as possible.”

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