On November 1, 2007, at 10:35:02 a.m. central daylight time, 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 in a rural area near Carmichael, Mississippi. The resulting gas cloud expanded over nearby homes and ignited, creating a large fireball that was heard and seen from miles away. About 10,253 barrels (430,626 gallons) of propane were released. As a result of the ensuing fire, two people were killed and seven people sustained minor injuries. Four houses were destroyed, and several others were damaged. About 71.4 acres of grassland and woodland were burned. Dixie Pipeline Company reported that property damages resulting from the accident, including the loss of product, were $3,377,247.
The National Transportation Safety Board determines that the probable cause of the November 1, 2007, rupture of the liquid propane pipeline operated by Dixie Pipeline Company 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.
The following safety issues were identified as a result of the investigation of this accident:
- The failure mechanisms and safety of low-frequency electric resistance welded pipe,
- The adequacy of Dixie Pipeline Company’s public education program,
- The adequacy of federal pipeline safety regulations and oversight exercised by the Pipeline and Hazardous Materials Safety Administration of pipeline operators’ public education and emergency responder outreach programs, and
- Emergency communications in Clarke County, Mississippi.
Safety recommendations to the Pipeline and Hazardous Materials Safety Administration, the Dixie Pipeline Company, the American Petroleum Institute, and the Clarke County Board of Supervisors are included in the report.
As a result of its investigation of the November 1, 2007, rupture of the liquid propane pipeline operated by Dixie Pipeline Company the National Transportation Safety Board makes the following recommendations:
To the Pipeline and Hazardous Materials Safety Administration:
Conduct a comprehensive study to identify actions that can be implemented by pipeline operators to eliminate catastrophic longitudinal seam failures in electric resistance welded (ERW) pipe; at a minimum, the study should include assessments of the effectiveness and effects of in-line inspection tools, hydrostatic pressure tests, and spike pressure tests; pipe material strength characteristics and failure mechanisms; the effects of aging on ERW pipelines; operational factors; and data collection and predictive analysis. (P-09-1)
Based on the results of the study requested in Safety Recommendation P-09-1, implement the actions needed. (P-09-2)
Initiate a program to evaluate pipeline operators' public education programs, including pipeline operators' self-evaluations of the effectiveness of their public education programs. Provide the National Transportation Safety Board with a timeline for implementation and completion of this evaluation. (P-09-3)
To the Clarke County Board of Supervisors:
Require and document that the Clarke County Central Dispatch emergency 911 personnel receive regular training and participate in regional exercises and drills pertaining to pipeline safety. (P-09-4)
To the American Petroleum Institute:
Revise American Petroleum Institute Recommended Practice 1162 to explicitly identify 911 emergency call centers as emergency response agencies to be included in outreach programs under a pipeline operator's public education program. (P-09-5)
To Dixie Pipeline Company:
Take measures to determine that all residences and businesses within your operating regions are included on your mailing list and receive mailings of safety guidance information. (P-09-6)
Implement procedures to evaluate the effectiveness of your public education program. (P-09-7)
Verify that all 911 emergency centers within your operating regions are included on your mailing list, invited to participate in operator-sponsored training activities, and receive mailings of safety guidance information. (P-09-8)