On 18 August 2014, the British Columbia government ordered an independent engineering investigation into the pond breach and a third-party review of all 2014 dam safety inspections for every permitted mines tailings pond in the province. The report found that the tailings dam collapsed because of its construction on underlying earth containing a layer of glacial till, which had been unaccounted for by the companys original engineering contractor. 
The report investigated whether the piezometers measuring the water pressure on the dam had been located correctly,  as the last readings, 2 August 2014, did not show any changes in the water pressure. In 2010, Mount Polley Mining Corporation's (MPMC) engineering firm reported a  crack in the earthen dam while working to raise it, and that piezometers were broken, which were later fixed.
In 2018, three engineers who worked on the tailings storage facility were charged by their professional association with negligence or unprofessional conduct.