PG& E has indicated that they believe a fatal natural gas explosion that occured in Northern California last September may have been the result of the gas pipe subsiding from soil movement.  The pipe explosion occurred September 9, leveled 38 homes, and killed eight people.  The National Transportation Safety Board, which is investigating the fatal explosion, may have a different viewpoint.  Although the NTSB has yet to release their final report, they have issued test results showing that at least 150 welds in the gas pipe that blew were defective.  The cause of the blast is sure to be highly contested, and it appears that PG & E may be attempting to divert blame prior to the issuance of the NTSB report.  PG & E's Director of Integrity Management (is this really a job title?) recently issued a statement blaming a possible geological event for the pipe failure.  Bob Fassett stated that the blast may have been triggered by settlement of the gas pipe, possibly after it was undermined by a leaking water main or sewer pipe.  Aerial photos of the site prior to the blast do not show any of the tell tale signs of soil movement, such as cracks in the street or adjacent flatwork.

    The NTSB had no comment about the PG & E comments.  They are expected to issue their final report in several months.