The cause of a March 2011 explosion in Minneapolis has been released by the Minnesota Office of Pipeline Safety in a final report on the matter.
Surrounding buildings and cars were damaged, neighborhoods were evacuated, and Interstate 35W was closed to traffic when a gas leak ignited in front of a Cub Foods store on East 60th Street and Nicollet Avenue.
The investigation found the couplings used in a CenterPoint Energy natural gas pipeline in front of the grocery store were not designed to sustain the weight of the soil, roadway, and traffic. Cub Foods employees had reported smelling gas in January 2009 and November 2010.
A CenterPoint spokeswoman said crews had checked the pipeline after those reports and did not find a leak. She said CenterPoint is reviewing the Office of Pipeline Safety's report and will respond in the coming week.
The report said CenterPoint is repairing other places in the pipeline that might leak, and is considering replacing portions of the pipeline.