Two occupants were severely injured. Douglas Adams, the attorney for the two victims, says the findings were not a surprise since they followed the investigation closely.
It was done by a firm hired by PG&E in conjunction with the CPUC. The line was installed 45 years ago. The report says two sections of plastic pipe were not fitted properly before they were fused.
Regular checks in the area found no leaks, but investigators say the leak probably developed just before the explosion with natural gas collecting in the crawl space of the house. The explosion occurred after homeowner John Lee Clark turned on a coffee maker.
PG&E said it replaced a mile of pipe following the accident and will continue to monitor for leaks.