03:47 PM PDT on Friday, July 7, 2006

By TERESA BELL, kgw.com Staff

HILLSBORO -- A large fire destroyed a Hillsboro restaurant and forced authorities to close off several roads during the morning commute Friday.

KGW Photo

Flames shoot up into the air as firefighters battle the three-alarm blaze at the Sweet Oregon Grill.

The blaze broke out at the Sweet Oregon Grill near the intersection of West Union Road and Cornelius Pass Road around 4 a.m.

When firefighters arrived, the restaurant was already fully engulfed.

The owners and employees reportedly stood nearby and watched solemnly -- some crying.

Firefighters say the blaze grew fast because of old wood in the structure.

Three alarms were called. Sixty firefights using 15 fire trucks eventually got the fire out, but the building will be a total loss, authorities said.

One firefighter sustained a minor back sprain while working on removing the steeply pitched roof. He was taken to a local hospital for evaluation and then released.

Lead investigator Doug Nolan stated that the fire origin and cause remain undetermined. Damage estimates indicate that two-thirds of the structure was a total loss.

Drivers were routed around the blaze during the morning commute onto 185th Avenue and NW Kaiser Road because a large section of Cornelius Pass Road was closed off.

Frank Mungeam also contributed to this story.