# NTSB Safety Recommendation P-77-004

**Citation:** P-77-004  
**Type / status:** guidance / guidance  
**Agency:** National Transportation Safety Board  
**Effective:** 1977-06-08  
**Published:** 1977-06-08

ENCOURAGE, COORDINATE, AND MONITOR DEVELOPMENT OF EQUIPMENT WHICH COULD BE USED TO DETECT THE LOCATION OF SINKHOLES IN THE VICINITY OF UNDERGROUND UTILITIES.

## Document text

NTSB safety recommendation P-77-004.

ENCOURAGE, COORDINATE, AND MONITOR DEVELOPMENT OF EQUIPMENT WHICH COULD BE USED TO DETECT THE LOCATION OF SINKHOLES IN THE VICINITY OF UNDERGROUND UTILITIES.

Priority: CLASS III

Overall Status: Closed - Unacceptable Action

Issued Date: 1977-06-08

Adopted Date: 1977-05-18

Overall Date Closed: 1979-02-02

Synopsis: ON AUGUST 8, 1976, A GAS EXPLOSION DESTROYED A HOUSE AT 1127 OAK STREET, ALLENTOWN, PENNSYLVANIA. THE GAS MIGRATED FROM A BREAK IN A 4-INCH CAST-IRON MAIN UNDER THE STREET, THROUGH LOOSE SOIL UNDER A CONCRETE SIDEWALK, AND INTO THE BUILDING THROUGH CRACKS AND OPENINGS IN ITS FOUNDATION.

Ntsbnumber: DCA76MP024

Report Number: PAR-77-02

Addressee Name: RSPA

Addressee Status: Closed - Unacceptable Action

Addressee Date Closed: 1979-02-02

Addressee Acronym: RSPA

Addressee Organization Type: G-Federal Government

Communication Date: 1977-09-30

Communication Type: Official Correspondence

Communication Contents: LETTER FROM MATERIALS TRANSPORTATION BUREAU: MTB IS FAMILIAR WITH THE UNIQUE PROBLEM THAT AFFECTS ALLENTOWN'S CAST-IRON MAINS. AT THE PRESENT TIME, WE DO NOT HAVE FUNDS AVAILABLE FOR THE DEVELOPMENT OF EQUIPMENT TO DETECT THE LOCATION OF SINKHOLES IN THE VICINITY OF UNDERGROUND UTILITIES. UGI CORPORATION AND SOME GEOPHYSICAL COMPANIES ARE INVOLVED IN R & D EFFORTS IN THIS AREA. MTB WILL CONTINUE TO ENCOURAGE THESE EFFORTS. 3/20/78 - MTB LTR: IT IS THE OPINION OF MTB THAT THE POTENTIAL PAYOFF FOR INCREASED SAFETY THROUGH RESEARCH AND DEVELOPMENT EFFORTS IN THIS AREA DOES NOT WARRANT RESOURCE INVESTMENT. MTB FINDS NO PRIVATE SECTOR PLANS TO DEVELOP SUCH DEVICES.

Addressee Acronym: RSPA

Addressee Organization Type: G-Federal Government

Communication Date: 1977-11-18

Communication Type: Official Correspondence

## Provenance

- Official: Yes
- Source: <https://data.ntsb.gov/carol-main-public/sr-details/P-77-004>
- Source ID: `ntsb-pipeline`
- SHA-256: `ac46d84fdc11d4e3dbd7dfb95cf130c449f948e2a73c948561c9f74e60cf8e3f`
- Retrieved: 2026-08-20T04:57:24.741Z
- Exported: 2026-08-24T00:18:12.082Z
- Document slug: `ntsb-recommendation-p-77-004`

### Source metadata

```json
{
  "recordKind": "ntsb_safety_recommendation",
  "safetyRecommendationNumber": "P-77-004",
  "recommendationMode": "Pipeline",
  "topicMode": "Pipeline",
  "ntsbNumber": "DCA76MP024",
  "priority": "CLASS III",
  "overallStatus": "Closed - Unacceptable Action",
  "overallStatusAcronym": "CUA",
  "overallDateClosed": "1979-02-02",
  "lastModifiedDate": "2016-11-15",
  "reportNumber": "PAR-77-02",
  "reportUrl": "https://www.ntsb.gov/investigations/Pages/DCA76MP024.aspx",
  "transmittalLetterUrl": "http://www.ntsb.gov/safety/safety-recs/recletters/P77_4.pdf",
  "addressees": [
    {
      "addresseeName": "RSPA",
      "addresseeStatusAcronym": "CUA",
      "addresseeStatus": "Closed - Unacceptable Action",
      "addresseeDateClosed": "1979-02-02",
      "addresseeDetails": [
        {
          "addresseeAcronym": "RSPA",
          "addresseeOrganizationType": "G-Federal Government",
          "isFromNtsb": false,
          "communicationDate": "1977-09-30",
          "communicationType": "Official Correspondence",
          "communicationContents": "LETTER FROM MATERIALS TRANSPORTATION BUREAU: MTB IS FAMILIAR WITH THE UNIQUE PROBLEM THAT AFFECTS ALLENTOWN'S CAST-IRON MAINS. AT THE PRESENT TIME, WE DO NOT HAVE FUNDS AVAILABLE FOR THE DEVELOPMENT OF EQUIPMENT TO DETECT THE LOCATION OF SINKHOLES IN THE VICINITY OF UNDERGROUND UTILITIES. UGI CORPORATION AND SOME GEOPHYSICAL COMPANIES ARE INVOLVED IN R & D EFFORTS IN THIS AREA. MTB WILL CONTINUE TO ENCOURAGE THESE EFFORTS. 3/20/78 - MTB LTR: IT IS THE OPINION OF MTB THAT THE POTENTIAL PAYOFF FOR INCREASED SAFETY THROUGH RESEARCH AND DEVELOPMENT EFFORTS IN THIS AREA DOES NOT WARRANT RESOURCE INVESTMENT. MTB FINDS NO PRIVATE SECTOR PLANS TO DEVELOP SUCH DEVICES."
        },
        {
          "addresseeAcronym": "RSPA",
          "addresseeOrganizationType": "G-Federal Government",
          "isFromNtsb": true,
          "communicationDate": "1977-11-18",
          "communicationType": "Official Correspondence",
          "communicationContents": ""
        }
      ]
    }
  ],
  "jurisdiction": "US"
}
```