TORONTO -- A Canadian-owned water bomber being used in the fight against the wildfires in Australia crashed Thursday, killing three American firefighters.

The C-130 Hercules aerial water bomber belonged to B.C.-based Coulson Aviation, which had leased it to the Australian government.

Company president Britton Coulson told CTV News Vancouver Island earlier this month that Coulson had "pretty much all" of its aircraft in Australia as part of the firefighting effort, including two C-130s.

Authorities have said little publicly about the cause or details of the deadly collision. Rural Fire Service Commissioner Shane Fitzsimmons said witnesses had described a "large fireball associated with the crash."

According to Coulson Aviation, the plane had left the community of Richmond, Australia, with retardant for a firebombing mission.

The three crew members who were killed are all Americans. Coulson has significant operations based in Oregon.

With files from CTV News Vancouver Island and The Associated Press