NSTAR GAS COMPANY — Gas distribution — incident on 2008-01-03

Gas distribution incident in MAYNARD, MIDDLESEX County, MA. Reported cause: 24. Reported consequences: 0 fatalities, 0 injuries, $152,449 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20080024.

Operator ID: 2652.

Reported incident date: 1/3/2008.

Cause detail: MISCELLANEOUS

Cause detail: NSTAR GAS WAS NOTIFIED OF A HOUSE FIRE BY THE MAYNARD FIRE DEPARTMENT AT 6:50 PM AND REQUESTED TO SHUT THE GAS TO THE BUILDING AT THE STREET. IT WAS BELIEVED THAT GAS MAY BE FUELING THE FIRE IN THE CRAWL SPACE AREA OF THE BASEMENT. THE HOMEOWNER HAD BEEN USING KEROSENE-FIRED TORPEDO HEATERS TO THAW FROZEN WATER PIPES IN THE CRAWL SPACE, IN THE VICINITY OF THE GAS SERVICE PIPING PASSING THROUGHTHE CRAWL SPACE. THE FIRE INVOLVED TIMBER FRAMING AND FLOORING ADJACENT TO AND ABOVE THE HEATER LOCATION. THE GAS SERVICE PIPING WAS BARE STEEL INSTALLED IN 1911 AND INSERTED WITH PLASTIC IN 1982. AFTER THE AREA WAS MADE SAFE NSTAR PERSONNEL OBSERVED BUBBLING FROM A POOL OF WATER ON THE DIRT CRAWL SPACE FLOOR, AT A THREADED UNION IN THE STEEL CASING PIPE. AN INDEPENDENT TESTING LABORATORY DETERMINED THAT THE PLASTIC PIPE FAILED DUE TO THE APPLICATION OF LOCALIZED HIGH TEMPERATURE MOST LIKELY FROM THE TWO BULLET TYPE SPACE HEATERS. THE LOCATION OF THE RELEASE OF GAS INTO THE ATMOSPHERE WAS POSSIBLE AT THE THREADED UNION. THE TWO SPACE HEATERS ARE POSSIBLE SOURCES FOR THE IGNITION OF THE RELEASED GAS. UPDATED BY PHMSA ON 1/15/2016 PER OPERATOR'S MARK UP. (PART A, QUESTION 4 - TYPE OF LEAK OR RUPTURE; PART C, QUESTIONS 2 FAILURE OCCURRED ON & 3 MATERIAL INVOLVED; AND PART F - APPARENT CAUSE, F7 - OTHER, QUESTION 24 MISCELLANEOUS; AND PART I - NARRATIVE).

PHMSA trend classification: significant incident, not serious, not fire-first.

PHMSA standardized cause: ALL OTHER CAUSES — MISCELLANEOUS.

PHMSA indexed costs: $152,449 reported total cost, $84,874.36 in 1984 dollars, $208,515.192 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.