First Air Boeing 737-200, C-GNWN, Flight 7F-6560. Resolute Bay, Canada.

RESOLUTE BAY, Nunavut — The Transportation Safety Board has completed the first stage of its investigation into the cause of the Aug. 20 crash of First Air flight 6560 near the Resolute Bay airport that killed 12 and injured three.

Chris Krepski, spokesman for the TSB, said Thursday that the board's team of 23 investigators was on its way back to Ottawa. The TSB investigators expect to take many months to complete their investigation into the crash of the Boeing 737.

Meanwhile, First Air said it has assumed responsibility for the final stages of the crash site remediation and environmental cleanup.

Qater Earth Science Assoc. Ltd., Atco and a local hunters and trappers organization will "assist and consult during the cleanup," First Air said.

The governments of Nunavut and the Northwest Territories and Aboriginal Affairs and Northern Development Canada have approved the plan.

Government inspectors are on-site to oversee the process, First Air said.