National Transportation Safety Board
Office of Public Affairs
The National Transportation Safety Board determined that the failure to adequately protect a pipeline from corrosion caused a rupture that resulted in two deaths. Damages, estimated at about $217,000, included roadway above the rupture, several buildings and adjacent woodlands.
On August 24, 1996, an 8-inch-diameter steel pipeline transporting liquid butane, operated by Koch Pipeline Company, LP, ruptured near Lively, Texas, sending a butane vapor cloud into a surrounding residential area. The butane vapor ignited as a pickup truck drove into the vapor cloud, killing both the driver and passenger. There were no other injuries reported at the time of the accident; however, approximately 25 families were evacuated from their homes.
The Board found that inadequate corrosion protection at the rupture site and numerous other locations on the pipeline allowed active corrosion to occur before the accident. The Board stated that disbonded tape coating most likely created locally shielded areas on the pipe that prevented cathodic protection, a corrosion mitigation method to protect underground metal pipes by way of electrical current, from reaching its surface. As a result, other areas in which rapid corrosion developed went uncorrected.
According to the Safety Board, the tape coating on the entire pipeline may have stress cracking and disbondment. Because no overall requirement exists for operators to evaluate pipeline coating conditions, problems similar to those that occurred on this pipeline could occur on other pipelines. Furthermore, the Board noted that this accident is an example of the continuing need for performance measures for adequate cathodic protection on liquid pipelines.
The Board concluded that the format and content of a company public education bulletin did not effectively convey important safety information to the public. Also, requirements for the content, format and periodic evaluation of public education programs can help pipeline operators ensure that their programs are effective.
As a result of this accident investigation, the Safety Board made recommendations to the Research and Special Programs Administration, Koch Pipeline Company, LP, and NACE International.
The recommendations included:
• Requiring Koch Pipeline Company, to evaluate the integrity of the remainder of its highly volatile liquid pipeline, including the condition of the coating and rehabilitating the pipeline as necessary;
• Revising federal regulations to include performance measures for the adequate cathodic protection of liquid pipelines;
• Revising federal regulations to include requirements for the content and distribution of liquid pipeline operators' public education programs;
• Establishing a procedure to promptly evaluate all data related to pipeline corrosion, such as annual cathodic protections surveys, field reports, internal inspection results, and coating condition data, to determine whether the pipeline's corrosion protection is adequate, and take necessary corrective action; and
• Developing a standard of microbial sampling and testing of external surfaces on an underground pipeline.
The Safety Board's complete printed report (PAR-98/02/SUM) will be available on the Web (http://www.ntsb.gov/publictn/publictn.htm) or from the National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia 22161; (703) 487-4650; (http://www.ntis.gov). The NTIS report number is PB98-916503.
The National Transportation Safety Board (NTSB) is an independent federal agency charged with determining the probable cause
of transportation accidents, promoting transportation safety, and assisting victims of transportation accidents and their families.