NTSB Safety Recommendation Letter P-96-007

Page 1Official PDFNational Transportation Safety Board Washington, DE. 20594 Safety Recommendation In reply refer to: P-96-7 Mr. Ronald C. Check, Jr. President Environmental Preservation Associates, Inc. 5290 West Coplay Road Whitehall, Pennsylvania 18052 About 6:45 p.m" on June 9, 1994, a 2-inch-diameter steel gas service line that had been exposed during excavation separated at a compression coupling about 5 feet north of the north wall of the John T. Gross Towers (Gross Towers), an eight-story retirement home. Gross Towers, located at 14th and Allen Streets (1339 Allen Street), is one of several subsidized-rent residence buildings operated by the Allentown Housing Authority (housing authority) in Allentown, Pennsylvania. Towers East, a 13-story building that is connected to Gross Towers, is also a rent- subsidy building for senior citizens that is operated by the housing authority. The separated service line, which was owned by UGI Utilities, Inc., (UGI), released natural gas at 55 psig pressure. The escaping gas flowed underground to Gross Towers, where it passed through openings in the building's foundation and filled the space beneath the mechanical room, which served as a combustion air intake reservoir for boilers. Gas then entered the mechanical room through openings in the floor. The gas then migrated to the building's other floors through an adjacent tower that housed the boiler exhaust stacks, through a trash chute, and through floor openings for electrical and other building services. At the same time, a backhoe operator, an employee of the Environmental Preservation Associates, Inc., (EPAI) was removing hel-contaminated soil from the excavation site and detected the odor of gas coming fiom the building. He heard a woman in a third-floor apartment shout to him about a heavy gas odor. The loader, another EPAI employee, opened a side door to the building that led to the boiler room and encountered a very heavy gas odor that "took my breath away." He told his foreman of his observation, and the foreman told the backhoe operator to shut off the machine. About 6 5 8 pm", the natural gas that had accumulated within the building was ignited, causing an explosion. A second explosion occurred about 5 minutes later. At the time of the 6652#

Page 2explosion, many of the Gross Towers and Towers East residents were out of the building. The accident resulted in 1 fatality, 66 injuries, and more than $5 million in property damage.' The National Transportation Safety Board determines that the probable cause of the explosion and fire was the failure of the management of EPAI to ensure compliance through project oversight with its own excavation requkements and those of the Occupational Safety and Health Administration. Contributing to the accident was the failure of the EPAI workmen to notify the UGI that the lime had been damriged and was unsupported. Contributing to the severity of the accident was the absence of an excess flow valve (EFV) or a similar device, which could have rapidly stopped the flow of gas once the service l i e was ruptured. Also contributing to the severity of the accident was the absence of a gas detector, which could have alerted the fire department and residents promptly when escaping gas entered the building. The EPAI had several oppartdties to prevent the separation of the service line. It could have supported (shored up) the excavation's side walls during the excavation, as it was required to do by both its own health and safety program and the Occupational Safety and Health Administration. Had the walls been shored up, the one next to the service line would not have collapsed and undermined the lime's support. The EPAI would have known that the walls were not shored up had it had a supervisor overseeing the project, as its own procedures required it to. Even after the wall collapsed, the EPAI still could have prevented the accident by telling the UGI that the service line was no longer supported, thus giving the company a chance to protect the line. The Safety Board concludes that the EPAI could have avoided the accident by shoring up the excavation, by having effective supervisory oversight, or by reporting the lack of pipe support and the damage to the UGI. The EPAI needs to ensure that the requirements of its health and safety program are followed on all future work projects, including the requirement that damage be reported to the owners of buried facilities. Before the Allentown accident, the workcrew had not had any formal training in excavation and trenching or in actions to take as a unit to protect lives and property in an emergency. The lack of training may account for why the crew did not shore the excavation site or tell the UGI that the gas line was unsupported. The crew foreman, despite not having any information about the construction of the gas lime, said that he thought the entire line was welded tubular steel. His assumption may have led him to believe that the line could be adequately supported by crossbucks. In any event, he made a critical choice in assuming that it would be safe to leave the gas l i e uncovered and exposed for 2 weeks. A more prudent course of action would have been to immediately inform the UGI that the line was exposed. 'For more information, read Pipeline Accident Report UGl Ut;l;/ies. lnc.,, Natural Gas Dirtribulion Pipehe Erp(os;on andFire# ,41lenIown, Pennsylvania, June 9, 1994 (NTSBIPAR-96-01).#

Page 33 Because the EPAI’s management failed to prepare the workcrew properly, the crew foreman did not notify the UGI about the unsupported line, left it unsupported for 2 weeks, and did not protect the line while performing operations that could damage it. The Safety Board believes that only the facility operator can assess the safety of gas lines and other buried facilities once they have been damaged or otherwise disturbed and that he can make the assessment only after investigating thoroughly, including reviewing his construction information. Consequently, the EPAI, as well as other excavators, should instruct its employees to notify the facility operator promptly any time excavating alters the support of a buried facility, deforms its structure, or harms its coating. Once the line and coupling separated, the EPAI could have l i i t e d the consequences. When the EPAI foreman was told about the strong odor of gas within the building, he should have immediately called “91 1.” Contrary to his postaccident statement, telephone records show that he did not attempt to call “91 1” until after the explosion. Had he immediately reported the emergency to the fire department, it would have known almost 15 minutes before the explosion, giving it enough time to respond, notify the UGI, initiate evacuations and building ventilation, and, using the UGI responders, shut off the flow of gas into the building, which would have either prevented the explosion or reduced its force. The Safety Board concludes that the consequences of this accident could have been significantly reduced had the foreman promptly called “91 1” and had his helper promptly told the occupants of the building to evacuate. Although it was after normal business hours, the foreman first called the UGI’s Lehigh Division business office (the EPAI had not obtained and provided the foreman with the UGI’s 24-hour emergency telephone number). Even after contacting the UGI, he did not say, and the UGI did not question, whether the odor of gas had been detected within the building. Had the UGI known that gas was already in the building, it probably would have told him to evacuate the occupants, which he could have done with the help of his crew and the bystanders. The UGI probably also would have notified the fire department, thus giving it more time to respond The Safety Board concludes that the excavation crewmembers did not evacuate the residents and the foreman did not call the fire department before the explosion because they had not been trained in handling an emergency. The Safety Board’s report* on a July 22, 1993, pipeline accident, which cost 2 lives and injured 12 persons, also involved excavation damage and issues similar to the ones in this accident. The report discussed how important it is for excavators to notify local emergency- response agencies promptly. In that accident, the excavator notified the pipeline operator promptly after gas was released, but he did not notify the local response agencies until more than 20 minutes later. Had the fire department been notified earlier, it might have been able to save lives and prevent injuries. ‘Brief of Pipeline Accident: Northern Sfam Power Oqwy Gac Pipeline Accidenf, .July 22. 1993, SI. Paul, Mimesofa ( DCA-WMP-DI I).#

Page 44 Since the accident, the crew foreman and the heavy equipment (backhoe) operator, as well as other employees, have each received 8 hours of training in trench construction and safety and 24 hours of training in confined-space entry and rescue training from the Maryland Fire and Rescue Institute, a part of the University of Maryland. However, the EPAI has not developed procedures to guide the actions of its workcrews, nor has it given emergency-responder training to those of its employees who excavate. 'The Safety Board believes that the EPAI and all other contractor excavators should train their employees in notifying local response agencies of emergencies and in what to do to save lives, such as evacuating endangered members of the public, while waiting for the representatives of the response agencies to arrive. The National Tmnsportation Safety Board therefore issues the following safety recommendation to Environmental Preservation Associates, Inc.: Instruct its employees on actions to take when buried facilities, such a s gas lines, are unsupported or damaged; such actions should include alerting local response agencies and residents of threatened buildings, initiating evacuations, and notifying facility owners. (Class 11, Priority Action) Cp-96-7) Also, the Safety Board issues Safety Recommendations P-96-2 to the Research and Special Programs Administration; P-96-3 to the States and the District of Columbia; P-96-4 through -6 to UGI Utilities, Inc.; P-96-8 through -10 to the Governor of the Commonwealth of Pennsylvania; P- 96-1 1 and -12 to the city of Allentown; P-96-13 to the International Association of Fire Chiefs; P- 96-14 through -16 to the Department of Housing and Urban Development; P-96-17 and -18 to the Allentown Housing Authority; P-96-19 to the Associated General Contractors; and P-96-20 to the National Utility Contractors Association. The National Transportation Safcty Board is an independent Federal agency with the statutory responsibility "to promote transportation safety by conducting independent accident investigations and by formulating safety improvement recommendations" (Public Law 93-633). The Safety Board is vitally interested in any action taken as a result of its safcty recommendations. Therefore, it would appreciate a response h m you regarding action taken or contemplated with respect to the recommendation in this letter. Please refer to Safety Recommendation P-96-7 in your reply. If you need additional information, you may call (202) 382-0670. Chairman HALL, Vice Chairman FRANCIS, and Members HAMMERSC"IT GOGLIA concurred in this recommendation. and By: GM im Hall(#