NTSB Press Release about Pipeline Rupture Investigation
Here’s the press release from the US National Transportation Safety Board:
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NTSB PRESS RELEASE
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National Transportation Safety Board
Washington, DC 20594
FOR IMMEDIATE RELEASE: October 14, 2009
SB-09-58
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NTSB DETERMINES FRACTURE ALONG SEAM CAUSED 2007 MISSISSIPPI PIPELINE EXPLOSION
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Washington, DC – The National Transportation Safety Board
determined today that the probable cause of the 2007 pipeline
rupture near Carmichael, Mississippi was the failure of a weld
that caused the pipe to fracture along the longitudinal seam
weld, a portion of the upstream girth weld, and portions of
the adjacent pipe joints.
On November 1, 2007, a 12-inch diameter pipeline segment
operated by Dixie Pipeline Company was transporting liquid
propane at about 1,405 pounds per square inch gauge, when it
ruptured, releasing about 431,000 gallons of propane, in a
rural area near Carmichael, Mississippi. As a result, the
propane began to vaporize and form a cloud that expanded
over nearby homes. Local emergency responders received
calls informing them of the smell of gas and the sighting of
white gas. Approximately seven-and-a-half minutes after the
rupture, the vapors ignited, creating a fireball. There
were two fatalities and several minor injuries.
The accident pipe was manufactured in 1961 using the low-
frequency electric resistance welding (ERW) process for
longitudinal seam welds. The majority of ruptures in ERW
pipe involve the longitudinal seams. At the time of the
accident, no confirmed in-service pipeline ruptures in girth
welds had been reported for the entire pipeline since it was
installed. Additionally, segments of the accident pipe had
been inspected multiple times since 1998, using in-line
inspection tools.
As a result of the investigation, the Safety Board issued
recommendations to the Pipeline and Hazardous Materials
Safety Administration, the Clarke County Board of
Supervisors, the American Petroleum Institute, and Dixie
Pipeline Company on testing of pipeline, public awareness,
and training and drills for 911 personnel.
A summary of the findings of the Board’s report is available
on the NTSB’s website at:
http://ntsb.gov/Publictn/2009/PAR0901.htm
Media Contact: Terry N. Williams
(202) 314-6100
terry.williams@ntsb.gov
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What do you think? Did they find the root cause? Comment at the link below.
