CAMPBELL — Firefighters battled a four-alarm fire at a commercial building Friday morning, according to authorities.

Crews responded to a fire in a three-story, 50,000 square-foot vacant commercial building in the area of Dell Avenue and Knowles Drive, the Santa Clara County Fire Department said in a 10:17 a.m. tweet. Fire crews first worked offensively inside the building, but “conditions deteriorated quickly” and authorities pulled the firefighters out of the structure into defensive mode, said County Fire Department spokesman Justin Stockman.

No injuries were reported.

“The damage is extensive,” Stockman said. “Once they go defensive, it’s well-involved. It’s difficult to say whether the structure will be a complete loss but it’s definitely a possibility.”

The fire was eventually upgraded to four alarms. Units were aided by the San Jose Fire Department, Fire Associates of Santa Clara Valley and the Campbell Police Department, Stockman said. People were asked to avoid the scene and keep drones out of the area.

Authorities also received multiple calls reporting smoke in the area, Stockman said, adding that the smoke was blowing southwest and crews were trying to reduce the smoke and fire “as fast as we can.”

Knowles and Dell were closed between Winchester Boulevard and Division Street.

Source: www.mercurynews.com