A faulty connection between the main pipeline and an abandoned tap might have caused a massive natural gas explosion last month in Bushland, according to a preliminary government report.
A report by the Pipeline and Hazardous Materials Safety Administration also outlines steps El Paso Natural Gas must follow to ensure the line’s safety.
“I’m not at liberty to comment on the order,” El Paso spokesman Richard Wheatley said. “Our investigation is continuing.”
The PHMSA found through visual analysis of the damaged Bushland pipe that a failure might have occurred at an abandoned tap connection on the 24-inch pipeline. Tap connections are used to branch secondary pipes off the main line.
The Nov. 5 rupture and subsequent explosion created a crater about 100 feet wide and 15 feet deep and released 98 million cubic feet of natural gas. The fire reduced one home to ashes and seriously injured three people inside. It also damaged several other homes and scorched several hundred square feet of land.
Connection failures similar to what might have caused the Bushland rupture occurred in El Paso-owned pipelines in 1994 and 2003.
A PHMSA report on a March 2003 pipeline rupture in Weld County, Colo., found a failure around a 4-inch lateral pipeline connection. No one was killed or injured by the rupture. The same report stated the episode appeared similar to a 1994 rupture.
The report on the Bushland rupture orders El Paso to follow several measures for the pipeline’s safety:
·The operating pressure should not exceed 609 pounds per square inch gauge, which is 80 percent of the pipeline’s threshold of 780 psig. Operating pressure at the time of failure was 762 psig.
·Mechanical and metallurgical testing of the failed pipe should be completed within 30 days of the issued order.
·Within 60 days, El Paso must submit a work plan that includes corrective action and verification of the factors that caused the pipe’s rupture.
·El Paso officials must file quarterly reports on the results of testing, costs, evaluations and repairs. The first report is due Dec. 31, according to the order.
A third party, Stress Engineering of Houston, is testing pieces of the failed pipe as per government regulations.
“All the information is being reviewed by PHMSA,” Wheatley said.
A spokesman for the government regulator said the actions required of El Paso – they include the time frames and additional filings – are typical when corrective orders are issued.
“We do require various types of information to be filed during the course of the investigation,” PHMSA spokesman Damon Hill said. “We do want operators to take corrective action as soon as possible.”
The most recent inspection of the failed pipeline was in 2003, according to the report. No “actionable anomalies” were found in the area of the failure, the report states.
El Paso replaced about 80 feet of the damaged pipe and restored service last month.