WHITE CITY — Fire investigators have wrapped up their search for a cause of the massive blaze that destroyed Davis Finish Products and damaged other businesses and structures on July 9, but they haven't found anything.

After talking to witnesses, studying photographs and videos from the community and evaluating clues at the scene of the four-alarm blaze, a team including investigators from Jackson County Fire District No. 3 and Oregon State Police have listed the cause of the fire as undetermined, District 3 Fire Marshal Don Hickman said.

Investigators collected photos and videos from people who stopped to see the spectacle and interviewed dozen of people who were in the area.

"In YouTube videos we could see how the fire developed and see it from lots of different perspectives," Hickman said. "We got almost a 360-degree view of it."

In the end, though, they couldn't pin down what started the fire inside the Davis building, investigators said.

The fire burned freely for hours, reaching temperatures of up to 1,900 degrees and destroying all the materials that might have shown clues about where and how the fire started, Hickman said.

Fire crews from Jackson and Josephine counties spent hours in intense summer heat battling the flames that consumed the 140,000-square-foot cabinet and door business, as well as Rogue Valley Post and Pole. It also damaged Highway Products Inc., Ferry Morse Seed Co. and a hobbyist's garage.

In all about 62 acres were scorched in the fire, which continued to smolder in underground pockets of wood waste for about a week.

Firefighters mopped up those hot spots for several days, then turned the efforts over to a private firefighting company hired by an insurance company, Hickman said.

The contractor provided a bulldozer to dig through decades of "duff" — sawdust, bark chips and other wood fragments that collected on and in the ground during regular operations of mills, a charcoal briquet plant and other manufacturers of wood products in the area — to expose hidden embers, Hickman said. The fire district delivered about 1 million gallons of water to soak the ground during the earth-moving, he said.

However, small fires could pop up from underground all summer, so the contractor will have crews monitoring the area, Hickman said.

Anita Burke is a reporter for the Mail Tribune. Reach her at 541-776-4485, or e-mail aburke@mailtribune.com.