DURANGO, Colo. -- Investigators were trying to determine what went wrong when a firefighter died while battling the Missionary Ridge wildfire in the southwest part of the state.

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The Oregon man died Tuesday while fighting the 72,935-acre fire north of Durango.

Allan Wyatt, 51, was working as a "contract faller" firefighter and died when a tree fell on him, according to 7NEWS. A preliminary investigation indicates Wyatt was looking in another direction when the tree fell. It was his first day on the fire lines. He was a resident of Ontario, Ore.

The accident happened on the east side of the Missionary Ridge fire, which was still advancing Tuesday. The county coroner was called to Jeep Trail Road, which is close to the Pine River Campground around 6 p.m. Tuesday. Wyatt was the first firefighter to die battling a blaze in Colorado since 1994.

Temperatures were as high as the mid-90s in the area around the fire. The blaze, which has destroyed 56 homes, was 55 percent contained.

Larry Floyd, operations manager for the east flank of the fire, said there was a significant risk that it could blow up.

``This is my fourth fire this year and I'm caught in new territory because I've never seen such a dry fuel source,'' he said. ``This is actually outside our realm of experience.''

Wyatt was at least the ninth firefighter to die in the line of duty nationwide this season and the sixth to die in Colorado, although he was the first to actually die on the fire line.

Five firefighters from Oregon died after a van carrying them to the Hayman fire crashed near Parachute, in western Colorado on June 21. Fourteen firefighters, all from Oregon, died while fighting a wildfire on Storm King Mountain near Glenwood Springs, Colo. on July 6, 1994.

Southwest of Denver, the 137,000-acre Hayman fire, the largest wildfire in state history, was fully contained Tuesday after destroying 133 homes and a business.