NTSB Safety Recommendation Letter P-97-039

Page 1Official PDFNational Transportation Safety Board 9 Washington, D.C. 20594 Safety Recommendation Date: .January 6, 1 9 9 8 In reply refer to: P-97-39 Mr. Steward Mcgaw Director, Municipal Utilities Associated General Contractors o f America 1957 E Street, N.W. Washington, D.C. 20006 A gas explosion on November 21, 1996, in the Rio Piedras shopping district of San Juan, Puerto Rico, resulted in 33 fatalities and 69 injuries. This accident, one of the deadliest in pipeline history, made 1996 a record year for pipeline fatalities. The San Juan accident accounted for more fatalities tlian occurred the entire previous year, and it vividly illustrates the tragic potential of a single excavation-damaged pipe. The National Transportation Safety Board determined that the probable cause of the propane gas explosion, fueled by an excavation-caused gas leak, in the basement of the Humberto Vidal, Inc., office building was the failure of San Juan Gas Company, Inc., to oversee its employees' actions to ensure timely identification and correction of unsafe conditions and strict adherence to operating practices; and to provide adequate training to employees.' Also contributing to the explosion was the failure of the Research and Special Programs AdministratiodOffice of Pipeline Safety to effectively oversee the pipeline safety program in Puerto Kco; the failure of the Puerto Rico Public Service Commission to require San Juan Gas Company, Inc., to correct identified safety deficiencies; and the failue of Enron Corporation to adequately oversee the operation of San Juan Gas Company, h e . Contributing to the loss of life was the failure of San Juan Gas Company, Inc., to adequately inform citizens and businesses of the dangers of propane gas and the safety steps to take when a gas leak is suspected or detected. The Safety Board has long been concerned about the number of excavation-caused pipeline accidents. In response to six serious pipeline accidents during 1993 and 1994 that were caused by excavation damage and to foster improvements in State excavation damage prevention programs, the Safety Board and the Research and Special Programs Administration (RSPA) -__ 'National Transportation Safety Board. 1997. San Juan Gas Company, IncEnron Carp. Propane Gas Explosion in San Juan, Puerto Rico, on November 21, 1996. Pipeline Accident Report NTSB/PAR-97/01. Washington, DC. 693 1#

Page 2L jointly sponsored a workshop in September 1994.2 This workshop brought together about 400 representatives from pipeline operators, excavators, trade associations, and local, State, and Federal government agencies to identify and recommend ways to improve prevention programs. The Safety Board recently completed a safety study that analyzed the findings of the 1994 workshop, discussed industry and government actions undertaken since the workshop, and formalized recommendations aimed at further advancing improvements in excavation damage prevention programs.’ Safety issues discussed in the study include the essential elements of an effective excavation damage prevention program; accuracy of information regarding buried facilities; and system measures, reporting requirements, and data collection. With respect to the accuracy of information regarding buried facilities, the Safety Board examined current underground detection technologies, mapping systems, and the use of subsurface utility engineering (SUE). Subsurface utility engineering is a process for identifying, verifying, and documenting underground facilities. Depending on the information available and the technologies employed to verify facility locations, a level of the quality of information can be associated with underground facilities. These levels indicate the degree of uncertainty associated with the information; level A is the most reliable and level D the least reliable. This categorization is a direct result of the source of information and the technologies used to verify the information. A comprehensive map and automated computer diagram of a construction site is developed as a SUE product; it depicts co-registered information for all utilities in that area. The SUE process identifies all utilities during a single coordinated effort. In this way, information known about one facility can beneficially affect the mapping of other utilities, and unknown facilities are more likely to be documented. By signing the SUE product, a professional engineer warrants the maps against errors and omissions and assunies liability for the accuracy of the information. The Federal Highway Administration (FHWA) considers SIJE an integral part of preliminary engineering work on highway projects receiving Federal aid. It has the potential to reduce facility conflicts, relocation costs, construction delays, and redesign work. In 1984, the State of Virginia began a SUE program, called the Utility Designation and Locating Program, and determined that there were substantial cost savings. A highway prqject in the city of Richmond used SUE work costing $93,553 to avoid an estimated $73 1,425 worth of expenses to move utilities had the highway projects not been designed to avoid conflict with underground facilities. Virginia’s estimate of cost savings, just in terms of avoiding utility relocations, was $4 saved for each dollar spent. Additionally, Virginia credits the process with reducing design time *National Transportation Safety Board. 1994 Proceedings of the E,xcavation Damage Prevention Workshop. NTSB/RP-95/01. Washington, DC. National Transportation Safety Board. 1997. Protecting Public Safety Through Excavation Damage Prevention. Safety Study NTSBISS-97/01 I Washington, DC.#

Page 33 by 20 percent? The utility coordinator for Maryland’s State Highway Administration estimates a savings of $18 for each dollar spent. Florida DOT found that it saved $3 in contract construction delay claims for each dollar spent on SUE. Variations in these estimates reflect different cost assumptions, geographic conditions, and system configurations. Twenty-six highway agencies have used SUE at some level on some projects: FHWA estimates a nationwide savings of $100 million a year as a result of SUE! Compiling comprehensive information on underground facilities can be expensive and labor intensive. Small contractors generally do not have the resources or expertise available to accomplish SUE on a regular basis; consequently, SUE is generally used on large construction projects such as those typical of highway development. Architects, engineers, and contractors should have ready access to information on the location of underground facilities to plan construction activities. The advantage of this information was recognized at the 1994 damage prevention workshop. The Safety Board concludes that providing construction planners with information on the location of underground facilities, referred to as “planning locates,” can reduce conflicts between construction activities and existing underground facilities The Safety Board is recommending, therefore, that the American Public Works Association (APWA) encourage one-call notification centers to work with their members to provide facility location information for the purpose of construction planning. The Standards Committee of the American Society of Civil Engineers (ASCE) is developing standards for depicting underground facilities on construction drawings. The Board thus believes that the APWA and the ASCE should address the accuracy of information that depicts subsurface facility locations on construction drawings. Further, the Safety Board believes that the Associated General Contractors of America should promote the use of subsurface utility engineering practices among its members to minimize conflicts between construction activities and underground systems. Therefore, the National Transportation Safety Board recommends that the Associated General Contractors of America: Promote the use of subsurface utility engineering practices among your members to minimize conflicts between construction activities and underground systems (P-97-39) U S. Department of Transportation, Federal Highway Administration. 1995. Subsurface Utility E,ngineering Handbook. FHWA-PD-96-004 @. 1-14), Washington, DC. November. According to the FHWA, Maryland, Pennsylvania, Delaware, North Carolina, and Arizona use SUE on an extensive basis. ‘ U.S. Department of Transportation, Federal Highway Administration. 1995. Subsurface Utility Engineering Handbook. FHWA-PD-96-004 @. 1-29), Washington, DC. November.#

Page 44 As a result of this safety study, the Safety Board also issued safety recommendations to the Research and Special Programs Administration, the American Public Works Association, the Federal Highway Administration, the Association of American Railroads, the American Short Line Railroad Association, and the American Society of Civil Engineers. The National Transportation Safety Board is an independent Federal agency with the statutory responsibility “. I 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 actions taken as a result of its safety recommendations and would appreciate a response from you regarding action taken or contemplated with respect to the recommendation in this letter. Please refer to Safety Recommendation P-97-39 in your reply. Chairman HALL, Vice Chairman FRANCIS, and Members HAMMERSCIJMIDT, GOGLIA, and BLACK concurred in this recommendation. By: Jim Hall Chairman#