# NTSB Safety Recommendation P-77-025

**Citation:** P-77-025  
**Type / status:** guidance / guidance  
**Agency:** National Transportation Safety Board  
**Effective:** 1977-09-27  
**Published:** 1977-09-27

INSTRUCT ITS CREWS TO ASCERTAIN POSITIVELY BY ALL POSSIBLE MEANS THE TYPE AND SIZE OF EXISTING GAS LINE FACILITIES BEFORE WORKING ON THEM.

## Document text

NTSB safety recommendation P-77-025.

INSTRUCT ITS CREWS TO ASCERTAIN POSITIVELY BY ALL POSSIBLE MEANS THE TYPE AND SIZE OF EXISTING GAS LINE FACILITIES BEFORE WORKING ON THEM.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 1977-09-27

Adopted Date: 1977-09-16

Overall Date Closed: 1978-11-21

Synopsis: ON MAY 25, 1977, AN EXPLOSION AND FIRE DESTROYED A BUILDING AT 65-67 ARCH STREET IN GREENWICH, CONNECTICUT. TWO ADJACENT BUILDINGS WERE ALSO DESTROYED AND ANOTHER BUILDING WAS HEAVILY DAMAGED. FIREMEN EVACUATED RESIDENTS FROM A TWO-BLOCK AREA 30 MINUTES AFTER THE EXPLOSION. TEN PERSONS REQUIRED MEDICAL TREATMENT FOR INJURIES CAUSED BY THE ACCIDENT.

Ntsbnumber: DCA77FP024

Report Number: None

Addressee Name: Connecticut Natural Gas Corporation

Addressee Status: Closed--No Longer Applicable

Addressee Date Closed: 1978-11-21

Addressee Acronym: CNG

Addressee Organization Type: S-State Government

Communication Date: 1977-10-13

Communication Type: Official Correspondence

Communication Contents: CONNECTICUT NATURAL GAS CORP. LTR: THE CNG CORP. SUSPENDED ALL HOT LINE INSULATION FITTING INSTALLATIONS UNTIL EVENTS SURROUNDING THE ACCIDENT COULD BE EVALUATED. CNG CORP. HAS IMPLEMENTED REVISED WRITTEN PROCEDURES TO REQUIRE A COMPLETE REVIEW OF EXISTING RECORDS PRIOR TO COMMENCING WORK. IT ALSO REQUIRES A TEST TAP TO DETERMINE THAT A PIPE IS A GAS CARRIER AND NOT A SLEEVE BEFORE ACTUAL HOT TAP IS PERFORMED. 2/1/78 - CNG LTR TRANSMITTING MATERIAL REQUESTED BY NTSB IN LETTER OF 1/24/77: CNG GUIDELINES FOR INSTALLATION OF HOT TAP INSULATOR FITTINGS, AND PROCEDURE TO INSTALL HOT TAP INSULATOR FITTINGS.

Addressee Acronym: CNG

Addressee Organization Type: S-State Government

Communication Date: 1978-01-24

Communication Type: Official Correspondence

## Provenance

- Official: Yes
- Source: <https://data.ntsb.gov/carol-main-public/sr-details/P-77-025>
- Source ID: `ntsb-pipeline`
- SHA-256: `0aa0d58e2dd114e25475630e64125e336ca31d7a80726fe7b0445f7b72092303`
- Retrieved: 2026-08-20T04:57:24.741Z
- Exported: 2026-08-24T17:56:06.151Z
- Document slug: `ntsb-recommendation-p-77-025`

### Source metadata

```json
{
  "recordKind": "ntsb_safety_recommendation",
  "safetyRecommendationNumber": "P-77-025",
  "recommendationMode": "Pipeline",
  "topicMode": "Pipeline",
  "ntsbNumber": "DCA77FP024",
  "priority": "CLASS II",
  "overallStatus": "Closed - Acceptable Action",
  "overallStatusAcronym": "CAA",
  "overallDateClosed": "1978-11-21",
  "lastModifiedDate": "2026-03-19",
  "reportNumber": "None",
  "reportUrl": null,
  "transmittalLetterUrl": "http://www.ntsb.gov/safety/safety-recs/recletters/P77_24_25.pdf",
  "addressees": [
    {
      "addresseeName": "Connecticut Natural Gas Corporation",
      "addresseeStatusAcronym": "CNLA",
      "addresseeStatus": "Closed--No Longer Applicable",
      "addresseeDateClosed": "1978-11-21",
      "addresseeDetails": [
        {
          "addresseeAcronym": "CNG",
          "addresseeOrganizationType": "S-State Government",
          "isFromNtsb": false,
          "communicationDate": "1977-10-13",
          "communicationType": "Official Correspondence",
          "communicationContents": "CONNECTICUT NATURAL GAS CORP. LTR: THE CNG CORP. SUSPENDED ALL HOT LINE INSULATION FITTING INSTALLATIONS UNTIL EVENTS SURROUNDING THE ACCIDENT COULD BE EVALUATED. CNG CORP. HAS IMPLEMENTED REVISED WRITTEN PROCEDURES TO REQUIRE A COMPLETE REVIEW OF EXISTING RECORDS PRIOR TO COMMENCING WORK. IT ALSO REQUIRES A TEST TAP TO DETERMINE THAT A PIPE IS A GAS CARRIER AND NOT A SLEEVE BEFORE ACTUAL HOT TAP IS PERFORMED. 2/1/78 - CNG LTR TRANSMITTING MATERIAL REQUESTED BY NTSB IN LETTER OF 1/24/77: CNG GUIDELINES FOR INSTALLATION OF HOT TAP INSULATOR FITTINGS, AND PROCEDURE TO INSTALL HOT TAP INSULATOR FITTINGS."
        },
        {
          "addresseeAcronym": "CNG",
          "addresseeOrganizationType": "S-State Government",
          "isFromNtsb": true,
          "communicationDate": "1978-01-24",
          "communicationType": "Official Correspondence",
          "communicationContents": ""
        }
      ]
    }
  ],
  "jurisdiction": "US"
}
```