NTSB Safety Recommendation P-91-019

NTSB safety recommendation P-91-019.

THE NTSB RECOMMENDS THAT THE CITY OF ALLENTOWN: COORDINATE WITH KNOWN UNDERGROUND FACILITY OPERATORS IN THE IMMEDIATE ALLENTOWN VICINITY TO DEVELOP SYSTEMATIC PROCEDURES FOR CENTRALLY REPORTING, DOCUMENTING, AND EXCHANGING INFORMATION ON THE LOCATION OF UNDERGROUND VOIDS DISCOVERED THROUGH EXCAVATIONS OR OTHER MEANS.

Priority: CLASS II

Overall Status: Closed - Unacceptable Action - No Response Received

Issued Date: 1991-08-06

Adopted Date: 1991-07-23

Overall Date Closed: 2002-03-22

Synopsis: ON 8/29/90, A NATURAL GAS EXPLOSION & FIRE DESTROYED TWO ROW HOUSES AT 421-423 NORTH FIFTH STREET & DAMAGED TWO ADJACENT HOUSES & THREE PARKED CARS IN ALLENTOWN, PA. ONE PERSON WAS KILLED, & NINE PEOPLE, INCLUDING TWO FIREFIGHTERS, WERE INJURED. THE NTSB'S INVESTIGATION DISCLOSED THAT WATER LEAKING FROM A CIRCUMFERENTIAL CRACK IN A 6-INCH CAST-IRON MUNICIPAL WATER MAIN BENEATH NORTH FIFTH STREET'S EAST SIDE HAD ERODED THE SOIL FOUNDATION OF A LOW PRESSURE (9 INCHES WATER COLUMN PRESSURE) 4-INCH CAST-IRON UGI CORPORATION (UGI) GAS MAIN BENEATH THE WEST SIDE OF NORTH FIFTH STREET. THE GAS MAIN SUBSEQUENTLY CRACKED CIRCUMFERENTIALLY AND NATURAL GAS FILLED THE VOID BENEATH THE PAVEMENT. NATURAL GAS THEN MIGRATED THROUGH THE SOIL & INTO THE BASEMENT OF 423 NORTH FIFTH STREET, WHERE IT IGNITED, EXPLODED, & BURNED. SUBSEQUENT METALLURGICAL EXAMINATIONS REVEALED THAT BOTH CAST-IRON MAINS WERE SIGNIFICANTLY WEAKENED BY GRAPHITIC CORROSION. THE WATER MAIN WAS INSTALLED IN THE LATE 1800S & THE GAS MAIN WAS INSTALLED IN 1903.

Probable Cause: Undermined and weakened segment of cast-iron gas main

Ntsbnumber: DCA90FP011

Report Number: PAB-91-01

Addressee Name: Commonwealth of Pennsylvania, City of Allentown

Addressee Status: Closed - Unacceptable Action - No Response Received

Addressee Date Closed: 2002-03-22

Addressee Organization Type: L-Local Government

Communication Date: 2002-03-22

Communication Type: Official Correspondence

Communication Contents: The Safety Board is interested in knowing whether and how its recommendations are implemented, both to ensure that the public is provided the highest level of safety, and to identify creative solutions that might be shared with others. Although on April 30, 2001, the Board requested information from the City of Allentown on actions taken or planned to implement the above three recommendations, to date, the Board has not received a response from the City of Allentown. Accordingly, Safety Recommendations P-91-19, P-96-11 and -12 are classified "Closed--Unacceptable Action/No Response Received." Should the City of Allentown provide information on the implementation of these recommendations, the Board will review the information and consider reclassifying the recommendations.

Addressee Organization Type: L-Local Government

Communication Date: 2001-04-30

Communication Type: Official Correspondence

Communication Contents: To date, the Safety Board has received no response from the City of Allentown to any of these recommendations, and we would appreciate being informed of what action has been taken to implement Safety Recommendations P-91-19, and P-96-11 and -12.