{"operation":"document","citation":"DCA94MP003","title":"UGI Utilities, Inc., Natural Gas Distribution Pipeline Explosion and Fire","source_type":"incident","agency":"National Transportation Safety Board","status":"current","official":true,"published_on":"1994-06-09","effective_on":"1994-06-09","summary":"Accident. in Allentown, PA, USA. on 1994-06-09. UGI Utilities, Inc.,. Leak/explosion/fire","machine_formats":{"json":"https://regulus.evalyn.ai/document/ntsb-case-dca94mp003.json","markdown":"https://regulus.evalyn.ai/document/ntsb-case-dca94mp003.md"},"app_url":"https://regulus.evalyn.ai/document/ntsb-case-dca94mp003","source_url":"https://www.ntsb.gov/investigations/Pages/DCA94MP003.aspx","body":"NTSB investigation DCA94MP003.\n\nEvent Type: Accident\n\nEvent Date: 1994-06-09\n\nEvent City: Allentown\n\nEvent State Or Region: PA\n\nEvent Country: USA\n\nPipeline Operator: UGI Utilities, Inc.,\n\nPipeline Type: Distribution\n\nAccident Type: Leak/explosion/fire\n\nCompletion Status: Ongoing\n\nTier1Name: Construction\n\nTier2Name: External/third-party damage\n\nOfficial NTSB investigation data. NTSB findings determine probable cause and make safety recommendations; they do not adjudicate civil liability or regulatory violations.\n\nWhat Happened\nAbout 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 from the north wall of John T. Gross Towers, an eight-story retirement home operated by the Allentown Housing Authority at Allentown, Pennsylvania. The failed UGI Utilities, Inc., service line released natural gas at 55 psig pressure, and the escaping gas flowed underground to Gross Towers. The gas passed through openings in the building foundation, entered the mechanical room through floor vents, and migrated to other building floors.\nAn Environmental Preservation Associates, Inc., employee, who had been using a backhoe to excavate fuel-contaminated soil from the area, detected the odor of gas and heard a third-floor resident shout that she smelled a strong gas odor. The employee went to a building entrance and encountered a very strong odor of natural gas. He told his foreman, who, after having the backhoe shut down, telephoned the gas company and the housing authority, telling them of the gas odor. The foreman then instructed other employees to locate and shut off the gas line valve.\nAbout 6:58 p.m., 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 explosion, 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\n\nWhat We Found\nWe determined that the probable cause of\nthe natural gas explosion and fire at Gross Towers in Allentown, Pennsylvania, was the failure of the management of Environmental Preservation Associates, Inc., to ensure compliance with OSHA's and its own excavation requirements through project oversight.\n\nContributing to the accident was the failure of the workmen from Environmental Preservation Associates, Inc., to notify UGI Utilities, Inc., that the line had been damaged and was unsupported.\nContributing to the severity of the accident was the absence of an excess flow valve or a similar device, which could have rapidly stopped the flow of gas once the service line 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.\n\nWhat We Recommended\nAs a result of this investigation, we made the following new safety recommendations.\n\nTo the Research and Special Programs Administration: Require gas-distribution operators to notify all customers of the availability of excess flow valves; any customer to be served by a new or renewed service line with operating parameters that are compatible with any commercially available excess flow valve should be notified; an operator should not refuse to notify a customer because of the customer’s classification or the diameter or operating pressure of the service line. (P-96-2)\n\nTo the States and the District of Columbia.: Require gas distribution operators to install excess flow valves in all new or renewed gas service lines, when operating conditions are compatible with commercially available valves, including service lines supplying schools, churches, and other places of public assembly.(P-96-3)\n\nTo the UGI Utilities, Inc.:\nRequire that people handling emergency calls determine whether escaping gas is likely to enter a structure, and if so, require that the information be quickly conveyed to “911.” (Class II, Priority Action) (P-96-4)\nModify its excavation-damage prevention program to include the review and close monitoring of any proposed excavation near a gas service line, including any line with unanchored compression couplings, that is installed near a building and that, if damaged, might endanger public safety significantly. (P-96-5)\nInstruct members of local governments and contractor groups in its service area about the threat to public safety posed by a gas line that is unsupported or damaged, and emphasize the importance of reporting such information immediately to the facility owner. (P-96-6)\n\nTo Environmental Preservation Associates, Inc.: Instruct its employees on actions to take when buried facilities, such as 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. (P-96-7)\n\nTo the Governor of the Commonwealth of Pennsylvania:\nRequire any person or entity that excavates to participate in the State's excavation\u0002damage prevention program.(P-96-8)\nDesignate a single State agency responsible for the State's excavation-damage prevention program; give the agency the power to levy administrative penalties. (P-96-9)\nRequire each contractor to outline the area of the proposed excavation before asking the facility operators to mark the locations of their facilities.(P-96-10)\n\nTo the City of Allentown:\nInstruct fire and other city inspectors to advise facility owners, such as gas companies, immediately about any suspected damage to their buried facilities or any lack of structural support. (P-96-11)\nRequire as an excavation-permit condition that the excavator instruct his workmen in how to help members of the public in the immediate vicinity of an emergency, how to notify the local response agencies and the owner of a damaged facility, and how to evacuate anyone who might be in danger. (P-96-12)\n\nTo the International Association of Fire Chiefs: Urge its members to instruct their inspectors to report observed or suspected damage to a buried facility, including lack of support, to the owner immediately.(P-96-13)\n\nTo the Department of Housing and Urban Development: Require the installation of excess flow valves in new and renewed gas services to buildings that the Department has approved for Federal rent subsidies. (P-96-14)\n\nPAR-96-01\n<<<PAGE 1>>>\n\nPB96-916501\nNTSB/PAR-96/01\nNATIONAL\nTRANSPORTATION\nSAFETY\nBOARD\nWASHINGTON, D.C. 20594\nPIPELINE ACCIDENT REPORT\nUGI UTILITIES, INC., NATURAL GAS DISTRIBUTION\nPIPELINE EXPLOSION AND FIRE\nALLENTOWN, PENNSYLVANIA\nJUNE 9, 1994\n/\nB(-)\n,, ,—, ‘\n6652\n-------\n\n<<<PAGE 2>>>\n\nAbstract: On June 9, 1994, a 2-inch-diameter steel gas service line that had been exposed during\nexcavation separated at a compression coupling about 5 feet from the wall of a retirement home\nin Allentown, Pennsylvania. The escaping gas flowed underground, passed through openings in\nthe building foundation, migrated to other floors, and exploded. The accident resulted in 1\nfatality, 66 injuries, and more than $5 million in property damage.\nIn its investigation of this accident, the Safety Board identified safety issues relating to pipeline\nexcavation damage prevention and rapid shut down of failed gas service lines.\nAs a result of its accident investigation, the National Transportation Safety Board issued safety\nrecommendations to the Research and Special Programs Administration, the Sates and the\nDistrict of Columbia, UGI Utilities, Inc., Environmental Preservation Associates, Inc., the\nGovernor of the Commonwealth of Pennsylvania, the city of Allentown, the International\nAssociation of Fire Chiefs, the Department of Housing and Urban Development, the Allentown\nHousing Authority, the Associated General Contractors, and the National Utility Contractors\nAssociation.\nThe National Transportation Safety Board is an independent Federal agency dedicated to promoting\naviation, railroad, highway, marine, pipeline, and hazardous materials safety. Established in 1967,\nthe agency is mandated by Congress through the Independent Safety Board Act of 1974 to\ninvestigate transportation accidents, determine the probable causes of the accidents, issue safety\nrecommendations, study transportation safety issues, and evaluate the safety effectiveness of\ngovernment agencies involved in transportation. The Safety Board makes public its actions and\ndecisions through accident reports, safety studies, special investigation reports, safety\nrecommendations, and statistical reviews.\nInformation about available publications may be obtained by contacting:\nNational Transportation Safety Board\nPublic Inquiries Section, RE-51\n490 L'Enfant Plaza, S.W.\nWashington, D.C. 20594\n(202) 382-6735\nSafety Board publications may be purchased, by individual copy or by subscription, from:\nNational Technical Information Service\n5285 Port Royal Road\nSpringfield, Virginia 22161\n(703) 487-4600\n\n<<<PAGE 3>>>\n\nUGI UTILITIES, INC., NATURAL GAS\nDISTRIBUTION PIPELINE\nEXPLOSION AND FIRE\nALLENTOWN, PENNSYLVANIA\nJUNE 9, 1994\nPIPELINE ACCIDENT REPORT\nAdopted: February 26, 1996\nNotation 6652\nNATIONAL\nTRANSPORTATION\nSAFETY BOARD\nWashington, DC 20594\n\n<<<PAGE 4>>>\n\n\n\n<<<PAGE 5>>>\n\nCONTENTS\nEXECUTIVE SUMMARY\nINVESTIGATION\nThe Accident\nPostaccident Events ...\nCommunity Response..\nPolice\nFire\nMedical\nHousing Authority.\nPreaccident Events........\nInjuries\nMedical and Pathological\n12\nPipeline Damage\n12\nPostaccident Site Inspection.\n12\nOther Damage\n13\nPersonnel\n14\nPipeline System Information..\n15\nSystem Ownership\n15\nGas Service Line History..\n15\nApplicable UGI Operations ...\n16\nEFVs\n16\nExcavation-Damage Prevention Plan.\n17\nEmergency Plan..\n19\nEmployee Training for Emergencies..\n19\nEmergency Preparedness...\n20\nHousing Authority\n21\nOperations\n21\nEmergency Preparedness.\n21\nEPAI Procedures\n22\nDrug and Alcohol Policy.\n22\nHealth and Safety Program\n22\nRegulations and Oversight\n23\nPennsylvania\n24\nDamage-Prevention Statute.\n24\nPipeline Safety Oversight..\n25\nOSHA Requirements\n27\nExcavation-Damage Prevention..\n27\nPostaciens isis and insper and inforeme...\n27\n29\n29\nPipe Inspection\nGas Leakage Tests......\n29\niii\n\n<<<PAGE 6>>>\n\nMetallurgy ............................................................................................................. 29\nPhone Records....................................................................................................... 30\nANALYSIS ................................................................................................................... 31\nExclusions ................................................................................................................... 31\nThe Accident ................................................................................................................... 31\nEmergency Response......................................................................................................... 32\nHuman Performance and EPAI Workcrew ....................................................................... 32\nGeneral .................................................................................................................. 32\nTraining ................................................................................................................. 34\nPreaccident Events ................................................................................................ 35\nUGI Operations and Procedures........................................................................................ 35\nGeneral .................................................................................................................. 35\nExcavation-Damage Prevention............................................................................ 35\nDamage Notification ............................................................................................. 36\nRapid Shutdown of Failed Service Lines.............................................................. 36\nPennsylvania’s Pipeline Safety Operations ....................................................................... 37\nPremarking Proposed Excavations........................................................................ 37\nExcavation-Damage Prevention Program ............................................................. 38\nHousing Authority Standards ............................................................................................ 38\nDetection of Released Gas .................................................................................... 38\nRapid Shutoff of Failed Service Lines .................................................................. 39\nRapid Shutdown of Failed Service Lines.......................................................................... 40\nExcavation-Damage Prevention........................................................................................ 44\nCONCLUSIONS ................................................................................................................... 47\nPROBABLE CAUSE ................................................................................................................... 48\nRECOMMENDATIONS .............................................................................................................. 49\nAPPENDIX A: Investigation and Hearing.................................................................................... 53\nAPPENDIX B: Rapid Shutdown of Failed Service Lines............................................................. 55\nAPPENDIX C: Time Line of Events ............................................................................................ 79\nAPPENDIX D: September 28, 1995, Letter to RSPA from Safety Board.................................... 83\nAPPENDIX E: Gas Piping Technical Committee Excavation Damage Prevention Guidelines\niv\n\n<<<PAGE 7>>>\n\nEXECUTIVE SUMMARY\nAbout 6:45 p.m. on June 9, 1994, a 2-inch-diameter steel gas service line that had\nbeen exposed during excavation separated at a compression coupling about 5 feet from\nthe north wall of John T. Gross Towers, an eight-story retirement home operated by the\nAllentown Housing Authority at Allentown, Pennsylvania. The failed UGI Utilities, Inc.,\nservice line released natural gas at 55 psig pressure, and the escaping gas flowed\nunderground to Gross Towers. The gas passed through openings in the building\nfoundation, entered the mechanical room through floor vents, and migrated to other\nbuilding floors.\nAn Environmental Preservation Associates, Inc., employee, who had been using a\nbackhoe to excavate fuel-contaminated soil from the area, detected the odor of gas and\nheard a third-floor resident shout that she smelled a strong gas odor. The employee went\nto a building entrance and encountered a very strong odor of natural gas. He told his\nforeman, who, after having the backhoe shut down, telephoned the gas company and the\nhousing authority, telling them of the gas odor. The foreman then instructed other\nemployees to locate and shut off the gas line valve.\nAbout 6:58 p.m., the natural gas that had accumulated within the building was\nignited, causing an explosion. A second explosion occurred about 5 minutes later. At the\ntime of the explosion, many of the Gross Towers and Towers East residents were out of\nthe building. The accident resulted in 1 fatality, 66 injuries, and more than $5 million in\nproperty damage.\nThe National Transportation Safety Board determines that the probable cause of\nthe natural gas explosion and fire at Gross Towers in Allentown, Pennsylvania, was the\nfailure of the management of Environmental Preservation Associates, Inc., to ensure\ncompliance with OSHA's and its own excavation requirements through project oversight.\nContributing to the accident was the failure of the workmen from Environmental\nPreservation Associates, Inc., to notify UGI Utilities, Inc., that the line had been damaged\nand was unsupported.\nContributing to the severity of the accident was the absence of an excess flow\nvalve or a similar device, which could have rapidly stopped the flow of gas once the\nservice line was ruptured. Also contributing to the severity of the accident was the\nabsence of a gas detector, which could have alerted the fire department and residents\npromptly when escaping gas entered the building.\nv\n\n<<<PAGE 8>>>\n\nIn its investigation of this accident, the Safety Board identified safety issues\nrelating to pipeline excavation damage prevention and rapid shut down of failed gas\nservice lines.\nAs a result of its accident investigation, the Safety Board issued safety\nrecommendations to the Research and Special Programs Administration, the Sates and the\nDistrict of Columbia, UGI Utilities, Inc., Environmental Preservation Associates, Inc., the\nGovernor of the Commonwealth of Pennsylvania, the city of Allentown, the International\nAssociation of Fire Chiefs, the Department of Housing and Urban Development, the\nAllentown Housing Authority, the Associated General Contractors, and the National\nUtility Contractors Association.\nvi\n\n<<<PAGE 9>>>\n\nINVESTIGATION\nThe Accident\nAbout 6:45 p.m. on June 9, 1994, a 2-inch-\ndiameter steel gas service line that had been\nexposed during excavation separated at a\ncompression coupling1 about 5 feet north of the\nnorth wall of the John T. Gross Towers (Gross\nTowers), an eight-story retirement home. Gross\nTowers, located at 14th and Allen Streets (1339\nAllen Street), is one of several subsidized-rent\nresidence buildings operated by the Allentown\nHousing Authority (housing authority) in\nAllentown, Pennsylvania. Towers East, a 13-story\nbuilding that is connected to Gross Towers, is also\na rent-subsidy building for senior citizens that is\noperated by the housing authority. (See figure 1.)\nThe separated service line, which was\nowned by UGI Utilities, Inc., (UGI) released\nnatural gas at 55 psig pressure. The escaping gas\nflowed underground to Gross Towers, where it\npassed through openings in the building’s\nFigure 1. Accident Location\nfoundation and filled the space beneath the\nmechanical room, which served as a combustion\nair intake reservoir for boilers. (See figure 2.) Gas then entered the mechanical room through\nopenings in the floor. The gas then migrated to the building’s other floors through an adjacent\ntower that housed the boiler exhaust stacks, through a trash chute, and through floor openings for\nelectrical and other building services.\nAt the same time, a backhoe operator, an employee of the Environmental Preservation\nAssociates, Inc., (EPAI), was removing fuel-contaminated soil from the excavation site and\ndetected the odor of gas coming from the building. He heard a woman in a third-floor apartment\nshout to him about a heavy gas odor. The loader, another EPAI employee, opened a\n1A compression coupling joins lengths of pipe by applying mechanical pressure through a gasket to the end surfaces\nof pipe lengths sufficient to retain the pipe lengths against movement for a specific internal gas pressure and to seal the\njoint against gas leakage. If the forces on the pipe are expected to be greater than the retaining capability of the coupling,\nthe pipes are to be anchored or otherwise prevented from moving out of the coupling.\n\n<<<PAGE 10>>>\n\n—\nB NORTH WALL OF\n~ GROSS TOWERS\nGAS\nMETER\nGAS SERVICE\nRISER\nm\nx\nz\nr\n1ST FLOOR z\nx PARKING LOT\nL\nSPACE UNDER x\nMECHANICAL ROOM x COMPRESSION\nx COUPLINGS GAS SERVICE LINE\nx\n\\~n a-r 80UlH N~\nGAS\nMAIN\nL O C A T I O N F O R E F V HAD IT BEEN INSTALLED\nv -\n4FT. 11 IN.\nFigure 2. Schematic of Gas Service Line\n\n<<<PAGE 11>>>\n\nside door to the building that led to the boiler room and encountered a very heavy gas odor that\n\"took my breath away.\" He told his foreman of his observation, and the foreman told the backhoe\noperator to shut off the machine.\nThe foreman said that he then went to his pickup truck and, using his cellular phone,2\ncalled the gas company and the housing authority, telling them that he was excavating near the\ngas line and smelled gas. He stated that he next made three attempts to phone \"911.\" He said that\neach time he called, there was no answer. He said he then moved his truck to another spot in the\nparking lot in case the phone signal to his cellular phone was being blocked. He said that at the\nnew location he again tried unsuccessfully to call \"911.\"\nAccording to the UGI’s records, the foreman's call was answered at 6:48 p.m. by UGI's\nCentral Gas Control at Reading, Pennsylvania. According to the UGI’s records, the foreman said\nthat there was a gas leak at 1337 (Allen Street) Gross Towers in Allentown and that the gas line\nhad been hit during digging. (The foreman acknowledged telling the UGI that he was digging\nnear the gas line and had detected the odor of gas, but said that he did not tell the UGI that he had\n\"hit\" the gas line.) At 6:52, the UGI received a second call, which was apparently from the\nforeman. The call was recorded as \"Cust [customer] just called back, said they definitely hit gas\nline and broke it.\" The UGI's procedures did not require Gas Control to notify the Allentown fire\ndepartment or any other emergency-response agency of either report about the release of gas\nbecause the caller did not indicate there was an imminent threat; consequently the fire department\nwas not called.\nAccording to the housing authority’s records, the foreman called the housing authority at\n6:55 and was connected to the after-hours answering service. The answering service’s records\nshow that the foreman advised that \"they [the EPAI] were digging and they think they got the gas\nline.\" At 7:06, according to the answering service, the foreman's message was relayed to one of\nthe housing authority's maintenance employees, who promptly went to Gross Towers.\nThe records of both the UGI and the housing authority of the foreman’s calls do not show\nthat he said anything about detecting a strong odor of gas within the building.\nWhile he was making the calls, the foreman said, he instructed the operator and the loader\nto trace the gas line back toward Utica Street until they found the shutoff valve. They found the\nvalve near the north edge of the parking lot, but were unable to close it. They lacked the\nnecessary tools to operate the below-ground valve. (Later, when the fire department\nrepresentatives arrived, the EPAI workmen did not tell them they had been unable to close the\nvalve.)\n2Details of the calls to and from the foreman's telephone appear later in the report.\n3\n\n<<<PAGE 12>>>\n\nAbout 6:50, the UGI telephoned its on-call serviceman for the Lehigh Division, which\nincludes the Allentown area, who was at his residence about seven blocks from Gross Towers.\nAt 6:55, he left for Gross Towers.\nThe foreman's calls to Gas Control were relayed electronically to the Lehigh Division\nOffice, which is staffed by two employees. When the office received the report, an alarm\nsounded to tell the office employees that the message was urgent. One of the employees\nradioed a construction and maintenance crew that was working about 7 to 8 miles north of\nGross Towers. He directed the crew to respond to the emergency.\nAbout 6:58, the natural gas within the building was ignited by one of several possible\nsources common in apartment buildings, such as the electrical arcs that are created when an\nelectrical appliance or a piece of\nequipment is turned on or off. The EPAI\nemployees stated that after the initial\nexplosion, a second one occurred about 5\nminutes\nlater.\nAfter the\nsecond\nexplosion, they observed fire within the\nbuilding. The loader said that he thought\nthe explosion and fire originated in the\narea of the boiler room.\nAt the time of the explosion,\nmany of the residents of Gross Towers\nand Towers East were out of the\nbuilding, either attending a nearby Bingo\ngame, walking around the adjacent\nshopping center, or sitting on the front\nlawn at the entrance of the building.\nwhich was on the south side.\nPostaccident Events\nA UGI employee at 12th and\nGordon Streets, about 2 1/2 blocks from\nGross Towers, was\nin his truck\nFigure 3. Back of Gross Towers after Accident\ncompleting work reports when he heard\nan explosion and saw a cloud of dust\nrising into the air. Although he was not on call to respond to emergencies, he began driving in\nthe direction of the dust cloud and radioed his dispatcher to find out whether he had received a\nreport on the explosion. The dispatcher replied that a gas release had been reported and that a\nserviceman was en route. The employee arrived at Gross Towers about 7:03. About a minute\n\n<<<PAGE 13>>>\n\nlater, the UGI on-duty serviceman arrived. The two men met with the fire department's\nemergency onscene coordinator and received his approval to shut off the gas line.\nThe UGI employees made their way through the debris to the rear of Gross Towers,\nwhere a natural gas-fed fire burned from the back of the mechanical room. They located the\nshutoff valve, near Utica Street, and, about 7:15, closed it. As a precaution, they also closed the\nservice-line valves at two gas meters just north of Gross Towers and then helped the emergency-\nresponse personnel. The fire in the mechanical room, which had spread through building utility\nchutes up to the fourth floor, died out from lack of fuel.\nPostaccident surveys of 115 residents show that three Towers East occupants, in units\n108, 408, and 902, had smelled gas immediately before the explosion and that two other\noccupants had smelled gas shortly before the explosion while they were in the mail room on the\nfirst floor. The occupant of unit 108 stated that he had reported the gas odor to \"911,\" but after\nthe explosion.\nCommunity Response\nPolice--At 6:58,3 a policeman working an extra job at a store at 14th and Allen Streets\nheard a loud explosion and radioed that information to the city’s Communication Center. He then\nran to Gross Towers and, to avoid the flames, entered the building through the windows to the\nright of the front entrance. As he entered, several bystanders apparently followed him in and\nhelped escort survivors out. Within minutes, a second, smaller explosion occurred within the\nbuilding. The officer told the people who were helping him to put any injured residents on the\nfront lawn as close as possible to the corner of 14th and Allen Streets and to take uninjured\nresidents to the corner of Madison and Allen Streets, an empty parking lot.\nOther police officers arrived from areas within a mile of Gross Towers. They helped\ntransport handicapped and elderly people from the stairways and, after putting on self-contained\nbreathing apparatus, did a room-by-room search for victims and survivors. When the officer who\nhad been the first to arrive decided that enough people were working to efficiently evacuate the\nbuilding, he began to triage the injured. As more officers arrived to help remove victims from the\nbuilding, he stayed outside to direct arriving emergency medical-service units. A total of 50\npolice officers, 8 members of the police reserves, and 12 fire police officers responded to the\nincident.\nFire--When the Communication Center alerted the fire department, at 6:59, it dispatched\nthree engine companies, one aerial unit, and one command car. When they arrived, the\nemergency onscene coordinator (coordinator), an assistant fire chief, learned that occupants were\ntrapped by heavy smoke on the seventh floor and that several residents were trapped in an\n3His call was the first to reach the Communication Center. The Center received its second call 45 seconds later. It\ncame from a customer at a nearby restaurant.\n5\n\n<<<PAGE 14>>>\n\nelevator. After UGI personnel shut off the valve, emergency-response personnel searched each\nfloor to ensure that all residents had been evacuated.\nThe fire department used the city's mass casualty incident plan, and the coordinator used\nthe fire department's incident command system. The command post was established on the front\nlawn of Gross Towers at 7:03; and at 7:04, the emergency-response staging area and emergency\nshelter were established at the Allentown Fairgrounds, about 1/2 mile southwest of Gross\nTowers, where approximately 200 residents and 150 family members were helped. At 7:21, a\nMedEvac helicopter was requested to transport burn victims. Buses were requested at 7:40 to\ntransport victims to the shelter at the fairgrounds, and by 7:49, the preliminary search of Gross\nTowers for victims was complete. The last injured resident was transported to a local hospital at\n8:45.\nThroughout the emergency, local agencies worked with each other to provide food and\nshelter for the displaced residents. The agencies included the housing authority; the Allentown\npolice, emergency medical-services, and public-works departments; the Lehigh Valley County\nEmergency Management Administration; the American Red Cross; the Pennsylvania Power and\nLight Company; and the UGI.\nMedical --The Communication Center notified Allentown's emergency medical services\nat 6:59, and it dispatched two Allentown and three Cetronia emergency medical-services units.\nThe first medical unit arrived at Gross Towers at 7:03. The total time for triage was 1 1/2 hours.\nA total of 15 emergency medical-services agencies dispatched 35 vehicles, including one\nMedEvac helicopter. The injured people were transported to seven area acute-care hospitals.\nHousing Authority--The housing authority's answering service called the EPAI foreman\nat 7:03, telling him that the housing authority had been notified of his 6:55 report. The housing\nauthority’s executive director arrived at Gross Towers about 7:25. He directed the identification\nand relocation of the more than 300 residents and the site security operations. Additionally, 30 to\n40 other housing authority employees were notified and went to Gross Towers to help.\nPreaccident Events\nThe housing authority decided to eliminate potential future fuel-leak problems by\nremoving a buried tank at Gross Towers and two more that were no longer needed at other\nlocations. The authority receives approximately $3 million in grant funds for stock modernization\neach year from the U.S. Department of Housing and Urban Development (HUD), and the\nauthority used a portion of the money to pay for removing the tanks.\n6\n\n<<<PAGE 15>>>\n\nThe housing authority solicited contract proposals from three engineers who it believed\ncapable of the work. The authority selected the least-cost proposal. The owner and principal of\nthe selected engineering firm (consultant) was a mechanical engineer registered as a professional\nengineer in Pennsylvania. He had had some experience in removing buried tanks and was aware\nof, but not thoroughly knowledgeable about, the excavation safety requirements of the\nOccupational Safety and Health Administration (OSHA), a part of the U.S. Department of Labor\nthat establishes safety standards to protect workers. The consultant did not seek advice or support\nfrom an engineer qualified in structures and soils engineering.\nThe consultant prepared plans, dated November 17, 1993, for removing the tanks. The\nplans consisted of a drawing showing the layout of the three sites and a work specification\ndocument applicable to all three. The drawing showed the approximate location of the buried\nfuel tanks but did not show the locations of other buried facilities even though it was known that\nGross Towers had a buried natural gas line. The plan and specifications included among other\nprovisions, the following ones:\n• The pavement in areas to be excavated was to be saw cut before the tanks\nwere removed.\n• All work was to be performed in accordance with the latest requirements of\nthe Pennsylvania Department of Environmental Resources and the U.S.\nEnvironmental Protection Agency.\n• Bidders were to examine the specifications, drawings, and the construction\nsites. In signing the contract, the successful bidder was to be considered as\nhaving made a reasonable attempt to ascertain the nature and location of the\nwork and to learn of the general and local conditions that could affect the\nwork and its costs. In signing the contract he was also to be considered as\nhaving acknowledged that he was as knowledgeable of the character, quality,\nand quantity of surface and subsurface materials or obstacles to be\nencountered as was reasonable after inspecting the site. He was to notify the\nhousing authority promptly, before conditions were disturbed, of subsurface or\nlatent physical conditions at the site that differed materially from those\nindicated.\n• The consultant was to be allowed to visit the work site, inspect it, and issue\nwritten reports to the housing authority on observed deficiencies.\n• The contractor was to ensure that no laborer or mechanic was required to work\nin surroundings or under conditions that were hazardous or dangerous to\nhis/her safety as determined under OSHA safety and health standards. The\ncontractor was to protect the lives, health, and safety of other people, to\nprevent damage to property, materials, supplies, and equipment, and to comply\nwith regulations and standards of 29 CFR 1926.\n7\n\n<<<PAGE 16>>>\n\n• The contractor was to protect from damage all existing improvements and\nutilities at or near the work site.\n• The contractor was to employ a competent supervisor who would be\nresponsible for all the construction practices and workmanship of all people\nemployed by the contractor or subcontractor so that the contractor, rather than\nthe consultant, would be obligated to exercise responsible control over the\nconstruction practices and workmanship.\n• Side slopes of excavations were to comply with local codes, ordinances, and\nrequirements of agencies having jurisdiction. Shoring and bracing, which was\nto be supplied by the successful bidder, would be required where sloping was\nnot possible. Excavation sides were to be maintained in safe condition until\ncompletion of backfilling.\nThe consultant stated in the specifications that he would review the on-site work in\nprocess to identify deficient conditions or instances of noncompliance with the contract’s\nrequirements. His contract with the housing authority called for him to attend the preconstruction\nmeeting with the successful bidder and to conduct periodic job conferences to ensure that the\nwork was performed in accordance with the contract.\nIn February 1994, using the consultant's plan and specifications, the housing authority\nadvertised for bids to remove each of the buried fuel tanks and to replace one tank. The fuel tank\nat Gross Towers was an 8,000-gallon one buried beneath the north parking lot and used to store\nheating fuel. The housing authority’s executive director served as the contracting officer on\nconstruction procurement, and its construction coordinator had project oversight responsibility to\nensure that the work was completed. The executive director had worked for the housing authority\nfor 33 years, of which he had spent 4 in his present position. He had had no construction\nexperience. The construction coordinator had worked for the housing authority for 15 years and\nhad been involved with construction before being employed by the housing authority.\nThe EPAI won the contract to remove the tank at Gross Towers. According to the\nminutes of the meeting that was held when the contract was signed, such matters as compliance\nwith the U.S. Department of Labor standards regarding payrolls were discussed. OSHA job\nsafety requirements were not discussed, and the consultant did not attend.\nOn May 18, the EPAI obtained a permit from Allentown to remove the tank at Gross\nTowers. The permit issued by the building department, which is staffed to perform building-\nconstruction inspections, did not require on-site inspection by a building inspector because no\nbuilding construction was involved. Also, the Building Officials and Code Administrator’s\n(BOCA’s) building code adopted by the city did not require or recommend on-site inspections of\nexcavation work. However, the permit was forwarded to the fire department for action\n8\n\n<<<PAGE 17>>>\n\nbecause the city requires on-site safety inspections of work that includes the handling of\nflammable liquids.\nAt 1:26 p.m., on May 19, an EPAI employee told the Pennsylvania one-call notification\ncenter4 that it planned to begin excavating at Gross Towers at 8:00 a.m. on May 23. He said the\npurpose was to remove an underground storage tank in the rear parking lot of the housing\nauthority, and he noted that the proposed excavation would be 12 feet deep. The notice center\ndisseminated the information to its member facility operators. The EPAI did not identify the\napproximate location of the proposed excavation with white paint, as is now done in some States,\nnor was it required to do so.\nOn May 23, the housing authority issued the EPAI a Notice to Proceed. The notice stated\nthat the EPAI was to \"carefully [note] and fulfill the requirements of the general conditions\nrelative to the submittal and approval of Workmen's Compensation and Manufacturers' and\nContractors' Public Liability Insurance.\" No mention was made of OSHA safety standards. The\nhousing director and the consulting engineer recognized that the site drawings did not include\ninformation on the locations of buried facilities and that they were depending on the contractor\nidentifying the locations by notifying the excavation-damage notification system so that the\nfacility owners would mark the locations before excavation was begun. Even though there were\nprovisions for the consultant to oversee the work project, he did not.\nWhen they received the EPAI’s excavation notice, the UGI's Lehigh Division5 employees\nchecked the UGI’s records for the address the EPAI had given for Gross Towers and concluded\nthat the address should have been given as 1339 Allen Street. At 2:25 p.m. on May 19, a UGI\nemployee telephoned the EPAI, using the telephone number the EPAI had given the one-call\ncenter, and left a recorded message that the UGI had a gas service line to Gross Towers. At 8:21\na.m. on May 20, a UGI employee marked the location of the service line on the asphalt paving\nwith yellow spray paint. He did not talk with any EPAI employees about the gas line’s location as\nnone were at Gross Towers while he was there.\nOn May 23, the EPAI moved its equipment to the Gross Towers north parking lot. It\nremoved the asphalt paving in the area to be excavated and began removing the soil above the\ntank. The foreman evaluated the soil being excavated as OSHA Type A, which is cohesive soil\nwith an unconfined compressive strength of 1.5 tons per square foot. (OSHA’s postaccident\nevaluation indicated that a visual evaluation of the soil should have shown that it was OSHA\nType C, which is a cohesive soil with an unconfined compressive strength of 0.5 ton or less per\nsquare foot.)\n4A one-call notification center is one part of an overall excavation-damage prevention program that is used by\nexcavators for communicating with buried-facility operators about planned excavations to allow the facility operators to\nmark the locations of their facilities in the area of planned excavation.\n5UGI's Lehigh Division is responsible for the gas system and its operations in Allentown, Bethlehem, Easton, and\nadjacent areas.\n9\n\n<<<PAGE 18>>>\n\nWhile an Allentown fire inspector was inspecting the EPAI's work, he saw the\nexcavation's west sidewall slide into the excavation, exposing the gas line, which was about 3\nto 4 feet west of the\ntank. The collapsed\nsidewall removed the\nsoil support from about\n30 feet of the gas line,\ncausing it to sag. (See\nfigure 4.)\nThe fire inspector\nsaid that he questioned\nthe EPAl foreman about\nthe need to secure the\ngas line. He said that the\nforeman told him that\nthe condition presented\nno problem because the\ngas line was\nan all\nwelded system. (The\nforeman later stated that\nbased on his experience,\nFigure 4. Gas Service Line after Explosion\nhe bel","truncated":true,"body_characters":243392}