# NTSB Safety Recommendation Letter P-77-001 through P-77-003

**Citation:** P-77-001 through P-77-003  
**Type / status:** guidance / guidance  
**Agency:** National Transportation Safety Board  
**Effective:** 1977-06-08  
**Published:** 1977-06-08

Official NTSB transmittal letter for safety recommendations P-77-001 through P-77-003, issued 1977-06-08.

## Document text

Page 1
NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. I S S U E D : June h , 1977 --__________-_--_______________^___I____- Forwarded t o : \ M r . Arthur E . Bone President U G I Corporation 2 2 5 Morgantown Road Reading, Pennsylvania 19611 \ SAFETY RECOMMENOATION(S) P-77-1 through P,-77-3 - i A t 2 p.m., on August 8, 1976, a gas explosion destroyed a house a t 1127 Oak S t r e e t , Allentown, Pennsylvania. The gas migrated from a break i n a 4-inch c a s t - i r o n main under the s t r e e t , through loose s o i l under a concrete sidewalk, and i n t o the building through cracks and openings i n i t s foundation. I/ A t 2 : 2 6 p.m., another house exploded across the s t r e e t from the s i t e of the f i r s t explosion. The f r o n t b r i c k wall collapsed i n t o the s t r e e t and trapped two firemen. The s t r e e t then caved i n d i r e c t l y i n f r o n t of the trapped firemen. The c a s t - i r o n gas main within the sinkhole broke i n t o several pieces; flames from the broken main were more than 10 f e e t high and hampered rescue of the trapped firemen. Two firemen were k i l l e d , 14 persons were injured, 4 buildings were destroyed, and several buildings were damaged. Because of a l a c k of coordination between U G I personnel and firemen as t o the r e s p o n s i b i l i t i e s of each during t h i s emergency, two gas meters were overlooked and were not shut o f f . This probably provided the source of i g n i t i o n f o r the second explosion. Gas was allowed to burn a f t e r each of the explosions because the firemen had been taught: "Burning gas w i l l n o t explode"; and I t I f n a t u r a l gas is burning outside, the firemen should make no - I/ For more d e t a i l e d information on t h i s accident read P i p e l i n e Accident Report, U G I Corporation, Natural Gas Explosions and F i r e s , Allentown, Pennsylvania, August 8, 1976, NTSB-PAR-77-2. 204819. I

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attempt t o extinguish a gas f i r e . " These statements, under most circumstances, a r e too simplified t o and attempts should be made t o modify t r a i n i n g mater provisions f o r events s i m i l a r t o t h i s accident. Therefore, the National Transportation Safety mends t h a t U G I Corporation: Revise i t s 1968 Guide for F i r e Fighters and tr by incorporating i n s t r u c t i o n s on how t o d e a l w i s i m i l a r to t h i s accident with p a r t i c u l a r emphasis on t Revise i t s emergency plans t o incorporate the r e v i s i became e f f e c t i v e October 1, 1976, t o 49 Code of Feder Regulations 192.615, and t o i n s u r e emergency response coordination with f i r e and other public o f f i c i a l s . P u l a r emphasis should be placed on the a v a i l a b i l i t y an proper use of combustible gas indicators. (Class 111 Longer Term Followup) (P-77-2) Expedite, i n conjunction with equipment manufacturers development of a survey u n i t t h a t could be used t o de the location of sinkholes i n the v i c i n i t y of c a s t - i r o mains. "Downward-looking" radar equipment should be i n v e s t i aated a s one Dossible means of survevine f o r sinkholes. I (Class 111, Linger Term Followup) (P-77-3) M D D , Chairman, BAILEY, Vice Chairman, McADAMS, HOGUE, and HALEY, Members, concurred i n the above recommendations. By: Webster B. Todd, . Chairman

## Provenance

- Official: Yes
- Source: <https://www.ntsb.gov/safety/safety-recs/recletters/P77_1_3.pdf>
- Source ID: `ntsb-transmittal-letters`
- SHA-256: `9635164aa6253e7205832c9311641e3c6521d74414981c2359fb95f534cc5173`
- Retrieved: 2026-08-20T04:55:47.446Z
- Exported: 2026-08-26T14:56:40.633Z
- Document slug: `ntsb-transmittal-letter-p77-1-3`

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