NTSB Safety Recommendation Letter P-84-042

Page 1Official PDFNATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. I S S U E D : September 1'7, 1984 ' Mr. G. H. Lawrence President American Gas Association 1515 Wilson Boulevard Arlington, Virginia 22209 Mr. J. D. Capps Executive Vice President and General Manager National L.P. Gas Association 1301 West 22nd Street Oak Brooks, Illinois 60521 Mr. Arie M. Verrips Executive Director American Public Gas Association 301 Maple Avenue West Vienna, Virginia 22180 \ SAFETY RECOMMENDAT I O N ( 5 ) i P-84-42 At 11:15 a.m. e.d.t., on October 17, 1983, while excavating for the installation of a large diameter, concrete, storm drain pipe, a backhoe operator snagged and punctured a 3-inch steel gas line on the south side of State Route 214, thereby fracturing a 3-inch cast iron valve connecting the 3-inch gas line to the 4-inch gas line on the north side of State Route 214 in South Charleston, West Virginia. Gas at 45 psig began to escape from both breaks and, while it seemed to be venting into the atmosphere, it was also migrating below ground. The contractor immediately notified Columbia Gas of West Virginia Inc., and gas company personnel were dispatched to the site to respond to the emergency. A t 1:52 p.m., the Foodland supermarket, located 35 feet from the fractured valve, exploded, and then burned. Eighteen persons who were inside the store and 1 gas company employee who was outside the building were injured; the supermarket and an adjacent commercial building were destroyed. i/ - 11 For more detailed information, read Pipeline Accident Report, "Columbia Gas of West Virginia, Inc., Explosion and Fire, South Charleston, October 17, 1983 " (NTSB/PAR-84/4). 3829-A/265#

Page 2-2- In this accident, an accurate sketch showing the 50-foot stub line did exist in t h i form of a work order for the line abandonment. An up-to-date inventory map also existei. which also showed the 50-fOOt stub line. However, the gas company engineer responsibls for locating the gas company facilities on the highway construction prints did not receiv either the work order sketch or the inventory maps, and he did not request them. Instead the gas company engineer used an older inventory map as a guide in locating the ga company facilities on the highway construction print. The older inventory map, which had been up-to-date when the engineer first was assigned to the highway construction project in 1977, showed the gas line as complete and in operation from the valve a t Foodland all the way to the residential community approximately 700 feet away to the south. However, even though a meeting was held between the gas company engineer and the operations personnel for the purpose of verifying the accuracy of the map which w a s to be sent to the contractor, neither the engineer nor the operations personnel wer precise when referring to where the 3-inch gas line was to be cut off. The operation personnel were referring to the gate valve at the end of the stub line, while company engineer w a s referring to the gate valve at its connection with the 4-inch ga line 50 feet away at Foodland. Because the work order and the inventory map showing t h existence of the stub line were not available to and, therefore, were not referred to by the engineer, and because the review of the construction map by all person? concerncr' failed to identify the inaccuracies in that map, the gns company supplied the contractox with a'i incorrect map. Some months before the accident, but after t h s map showing the abandoned gas line had been provided to the contractor, the contractor blasted rock through the area and removed 300 feet of the 3-inch gas line (south of the end of the stub line) while making the initial grading for the storm drain project. Having succrssfully' blasted in that area. having removed most of the 3-inch gas line, and having n m:ip that showed an a gas line marked on it, the contractor had reason to believe [hat the path for ad excavation was clear of gas lines under pressure. The gas company inventory map used by the m x i plant supervisors to locate valve, to shut off the flow of escaping gas accurately showed the location of the 3-inch cas iron, gate valve at the connection of the 3-inch gas line with the 4-inch gas liri away from Foodland. Unfortunately, the m m failed to show some critical information: the depth of the valve (7 feet), that it was laid on its side with its valve stem horizontal, and that there was no hand wheel to operate it. If the area plant supervisors could have read this information directly from the map, they would not have wasted valuable time in trying to locate and close it on the day of the accident. The gas company's written procedures involving damage to company faciliti quite specific as to actions to be taken to protect the public and checks to he ma gas migrating beyond the immediate leak site. Specifically mentioned in the pro are gas checks adjacent to buildings and inside buildings, and evacuation of building None of these prescribed procedures were followed in this accident. All respo company personnel (the serviceman and the area plant supervisors) were aware of severity, but none of them followed the written procedures calling for them to check gas adjacent to buildings and inside buildings, and to evacuate buildings. All of t h stated that since the gas was venting freely into the atmosphere. in their opinion, it - presented no problem.#

Page 3-3- The gas company serviceman, who arrived shortly after the backhoe snagged the 3-inch line, asked a person leaving Foodland if there were any gas odors in the store. Because he was told that everything was all right, he did not check again. Apparently, he did not realize that it takes time for gas to accumulate under a black-topped parking lot, to migrate toward a building, to pool underneath the building, and to enter the building in sufficient quantity to be noticeable. The area plant supervisors also failed to follow any of the same company procedures. They too thought that since gas was venting into the atmosphere, it posed no problem, and because they were more concerned with trying t o find valves t o shut off the flow of gas to the rupture, they did not check inside Foodland. The serviceman and the three area plant supervisors testified that the gas seemed to be venting into the atmosphere through the water valve boxes and that they were not overly concerned about the buildings. Unfortunately, because of this attitude, they passed on misinformation to the co-manager of Foodland telling him that everything was under control. The gas company area plant supervisors forgot or ignored the fact that gas under pressure can migrate, and that a black-topped parking lot provides an excellent lid to hold escaping gas in the ground and to allow gas to travel substantial distances beyond. After arriving on the scene, gas company personnel should have broken through the black-topped parking lot between the leak and Foodland and should have used a combustible gas indicator (CGI) to check for gas; a gas indication of any amount would have alerted them to the threat of gas migration. They then should have checked for gas using a CGI adjacent to Foodland and then inside the supermarket; the presence of gas a t these locations undoubtedly would have led to the evacuation of Foodland and adjacent buildings. Since there were few people in the store, 18 at the tjrpe. of the explosion, evacuation would not have been complicated or time-consuming. These three steps could have been carried out by one person in a continuous manner before the gas buildup reached critical proportions. If gas company emergency procedures had been followed, persons could have been evacuated before the explosion and personal injuries would have been prevented. All of t h e gas company personnel at the accident site had received company training in these procedures, but that training failed to motivate gas companv personnel to take correct, positive action when it was most needed. This accident demonstrates the need for more intensive training in emergency procedures for all gas company personnel who must be dispatched to investigate leak complaints or pipeline damage. This phenomenon of gas migration into buildings was first investigated by the Safety Board in a pipeline accident involving the Lone Star G a s Company, North Richland Hills, Texas, on October 4, 1971, 2/ wherein 'I. . .an accumulation of natural gas which had leaked from a broken service-line connection and had migrated up and under the concrete slabs of both houses." Since that time, the Safety Board has investigated more than 1 6 accidents involving gas migration and the ensuing explosions and fire. The Board continues to be concerned about this problem and continues to emphasize the importance of checking for gas migration a t leak sites. Since 1970, the Safety Board has urged more extensive use of systems and methods to rapidly shutdown failed pipelines. In the introduction of its Special Study, "Effects of Delay in Shutting Down Failed Pipeline Systems and Methods of Providing Rapid Shutdown," 3/ - the Board states, in part: - 2/ For more detailed information, read Pipeline Accident Report-"Lone Star Gas Company, North Richland Hills, Texas. October 4, 1971" (NTSB-PAR-72-3). - 3/ Special Study, "Effects of' Delay in Shutting Down Failed Pipeline Systems and Methods of Providing Rapid Shutdown" (NTSB-PSS-71-1).#

Page 4-4- In almost all recent pipeline accidents, the delay in shutting down thc failed pipeline system has resulted in an increased magnitude of catastrophe. Had the flow of gas or hazardous liquid been stopped soon after the initial rupture, the effects of many accidents would have bee minimized or eliminated. With the ever increasing use of pipelines f natural gas and other hazardous materials and the proximity of thes lines to expanding populated areas, it is imperative that systems an methods be developed and put to use which will provide for the shutting down of failed pipeline systems. Since the study, the Safety Board has investigated more than 22 accide by, or intensified by, delay in shutting down failed pipeline facilities. The October 17, 1983, accident exemplifies the effects of not shutting down a failed pipeline facilitv rapidly. The puncture notification at 11:lfi a m by Holloway to the gas company and the arrival of the gas company serviceman about 11:20 a.m., were timely actions, as were the gas company serviceman's initial survey of the situation (a severe leak) and call for additional help about 11:40 a.m. Additional help arrived about noon and a gas company area plant supervisor arrived about 12:lO p.m. Up to this point the gas company response, situation survey, analysis of leak severity, and crew arrival were conducted within a reasonable time frame. However, from 12:lO p.m. until the explosion at 1:52 p.m. (1 how. 42 minutes later) the gas company crew and three area plant supervisors searched for a valve next to Foodland for an extended time and could not find it, searched for critical valve No. 246 for an extended time and could not find it. selected a location to squeeze off the 4-inch plastic gas main, requested a backhoe to excavate the gas line a t th' location, and updated the dispatcher by radio, but never gave considesation to checltin for gas accumulations in buildings or to the desirability of evacuating buildings. While the actions of the gas company employees are difficult to unde considering the leak severity, several factors that contributed to these time delays warrant examination. First, the map of the gas company facilities in the Foodland area showed a 3-inch valve in the parking lot, but it did not show that it was 7 feet deep or that it was lying on its side without a hand wheel to operate it. Had this information been shown on the map that gas company personnel were using. they would not have waste time trying to locate the valve since it would have been evident that it would require backhoe and shoring to reach it, both time-consuming activites. Second, critical No. 246, which was supposed to have been inspected and operated on February 5 , had been covered over with soil and could not be located. It should have been evid the gas company employees that the measuring points shown on the inventory map locate this valve were buried and would be difficult and time-consuming t o locate that since they could not locate the telephone pole which was shown to be 38 feet valve No. 246, they should have concentrated sooner on other shutoff valves further the system. Finally, after the explosion, the gas company did not shut off until 3:20 p.m., almost 4 hours after the initial notification and almost 1 1 / 2 hours afte the explosion; an unreasonable delay in shutting down a failed facility when other valve were accessible. The final shutoff was made by squeezing the 4-inch 1,000 feet west of the fractured 3-inch gate valve, but by this time, a been done. As a result of its investigation, the National Transportati recommends that the American Gas Association, the National L. P. Ga the American Public Gas Association:#

Page 5-5- Notify its member companies of the circumstances of the accident in South Charleston, West Virginia, on October 17, 1983, and urge them t o review their procedures for maintaining current, accurate system maps to emphasize the importance of rapid shutdown of failed gas facilities, and to emphasize their procedures for gas leakage in training programs for their personnel. (Class II, Priority Action) (P-84-42) BURNETT, Chairman, GOLDMAN, Vice Chairman, and BURSLEY and GROSE, Members, concurred in these recommendations. L Chairman#