天美网站传媒传媒

Officials say a sinkhole north of Detroit that damaged homes and cost $75 million to fix was caused by human error that allowed the quick release of waste and water into a sewer line.

Macomb Public Works Commissioner Candice Miller said that an assessment determined the surge fractured the pipe in Fraser which drew in sand and created a void in the surrounding soil.

The pipe collapsed and caused the Dec. 24, 2016, sinkhole which grew to football field-size.

But the problem started in 2014 when a gate was closed to hold back sewage for pipe maintenance. Miller said the gate was supposed to be gradually raised to allow the flow’s release over several hours. She said that wasn’t done properly on a number of occasions.

She said an insurance claim will be filed to recover some costs.