The National Transportation Safety Board is releasing a preliminary report on the gas emergency that resulted in explosions and one death in Merrimack Valley last month.
It blames a high-pressure natural gas released into a low-pressure Columbia Gas distribution system for the series of explosions on September 13th.
Over 130 structures were damaged in Lawrence, Andover, and North Andover as a result.
The report found a gas monitoring facility in Columbus, Ohio did receive two high-pressure alarms just minutes before the explosions began, but workers at the center had no way to close or open valves.
NTSB officials say there report is not final and much work needs to be done. It could be several months before a final report is issued.
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