An investigation by the National Transportation Safety Board has not found any signs of external corrosion, dents, or gouges on the pipeline damaged in a deadly explosion in September. Thus far, there is no reason to believe that any external excavation caused the pipeline rupture and explode that night. The explosion killed eight people, and injured dozens of others. Several houses were damaged in the blaze.

While investigators have not found any signs of corrosion, they have found plenty of welding seams. That does stand out, because the company that operated the pipeline, Pacific Gas & Electric has insisted that its pipes were seamless. Los Angeles personal injury lawyers expect more investigations into this aspect, especially as it indicates that PG&E either withheld information, or was simply not aware of the state of its own pipelines.

The NTSB is also looking at inspections conducted by the company on the pipeline, which was built in 1956. The agency investigators are especially looking at why the company conducted less sophisticated inspections of its pipeline, without using high-tech methods, like sending a robot into the pipe.

PG&E had reason to be concerned about that particular stretch of pipeline. That pipeline had been labeled “high risk” in 2007, and PG&E had planned to raise funds for repairs of the pipeline by billing ratepayers. However, those plans were inexplicably dropped the following year.

The NTSB investigators are also looking at why it took crew members of PG&E approximately 90 minutes to shut off the gas supply to the neighborhood the night of the fire.