At 3:30pm on December 2, 1973, an explosion followed by an intense fire killed three persons, injured two others, and destroyed a house on thye outskirts of Charleston WV.
The local rescue squad, two fire departments, and gas company personel evacuated the injured, extinguished the fire, and shut off gas to the building. Fire, fueled by natural gas which had saturated the soil, later rekindled briefly in the ground around the house.
Two pit-hole leaks were found in the 2-inch gas main, operated at 39 psig, which served the area; the leaks were 11 feet from the house and 1 foot from the concrete driveway which led to the house.Gas company personnel later repaired both leaks without shutting of the has main or interrupting service to any other customers.
We determined that the probable casue of the explosion and fire was the ignition, by an unknown source, of an accumulation of natural gas which had leaked from two corrosion holes in the nearby 2 inch gas main.
Contributing to the intensity of the ensuing fire was the large amount of natural gas which had acculated in the attic and between the original exterior walls of the house and a newer exterior brick veneer.
Contributing to the accident was the fact that none of the victims reported previously detected gas odors to the gas company or to the fire department. This was partially the result of the fact that the gas company's educational program submierged warnings and instructions within promotinoal material not heeded by the customer and did not inform the customer of the possible consequences of failure to report a gas odor to the gas company or to leave the premises.
As a result of this investigation, we made the following safety recommendations.
To the Office of Pipeline Safety of the Department of Transportation:
- Amend 49 CFR Section 192.723 to require more frequent leak surveys on older, uncoated, and cathodically unprotected pipelines than required currently. (P-74-29)
- Amend 49 CFR Section 192.615(D) to better define the intent of a public education program to warn against the full range of hazards of natural gas, to require retainable and specific instructions and placards of how to detect hazards, what to do, and why action is necessary. (P-74-30)
To the American Society of Mechanical Engineers Gas Piping Standards Committee:
- Develop guidelines to aid pipelines operators determine when to conduct leakage surveys on various types of pipe. These guidelines should take into account age of pipe, general condition of pipe, class location of pipe and metallurgy of pipe. (P-74-31)
- Develope guidelines to aid pipeline operators in determining areas of active corrosion as required by CFR 49 192.457(B) (P-74-32)
To the American Gas Association (AGA): Investigate the availability, economic feasibility, and practicability of gas vapor detectors currently manufactured and explore the possibility of their installation in manholes, conduits, basements, and other substructures for the automatic detection and reporting of natural gas vapors. If none are found acceptable, sponsor research to develop such a detector. (
P-74-33)
To Columbia Gas of West Virginia, Inc.:
- Conduct more frequent leak detection surveys on those areas where the gas pipelines are old, uncoared, and cathodically unprotected. (P-74-34)
- Initiate a more intense general public and gas customer information program as to the nature, characteristics, and hazards of natural gas and the steps to be taken when it is encountered. (P-74-35)
- Initiate a thorough survey to determine the areas of active corrosion on the entire length of this 2 inch gas main from its junction with the 3 inch has main at bakers form and similar pipes in its system. Make excavations for the physical examination of these pipes when indicated by the survey and replace or repair the pipe where indicated. When finished, place these pipes under adquate cathodic protection. (P-74-36)
