CHATTANOOGA (WRCB)-- Sparing the 'Old Farmer's Market is a battle that Chattanooga firefighters knew was lost, before it began.

"All we could really do was surround it and pound it with a bunch of water," CPD spokesman Bruce Garner says. "And put out the hot spots to go with it."

A two-hour battle, to control flames in what had amounted to little more than a shell.

"No power, no plumbing, no water service, so it was supposed to be empty," Garner says.

Except for, as firefighters and police put it, "unauthorized occupants; folks either making a home inside, or passing through. Chattanooga Police questioned one man, after reports that he had set fire to a mattress.

That man has not been named, nor arrested.

"There was simply not enough evidence to work with to pin it down as to whether it was accidental or whatever," Garner says.

"It'll be a slow slog to come up with a cause."

Among their questions; how could flames get through, or over, three cinder block firewalls, designed to prevent them from doing just that?

"There's not much left, to pore over for evidence," Garner says.

"The building was slated to be demolished anyway," City of Chattanooga spokesman Richard Beeland says. "This may just make it happen a little sooner."

Given that fate, fire investigators have assessed the damages at 'zero dollars,' Garner says.

Chattanooga bought the property for $775,000 in 2006 as a site to expand services for the homeless. Buildings directly across 11th Street house the Community Kitchen and similar services.

Revised plans have transformed the project into a proposal now billed as the Hamilton County Homeless Health Care Center. But inspectors first must determine whether the ground harbors no hazardous material, according to County Mayor's spokesman Mike Dunne.

The project also is eligible for federal grants, Dunne says. It's not clear whether that money is 'time-sensitive'; use, or lose.

"The city will make sure that it will be cleaned up if it was structurally unsound," Beeland says.

The rest of the complex, from the Onion Bottom section on back, is fine, he maintains. "The fire shouldn't impact our plans for renovation and conversion into a new police sub-station."

Late Friday morning, crews began clearing debris and flammables from the rest of the complex. They were clad in white jumpsuits and surgical masks.

"No sense tempting fate," one tells Eyewitness News off camera.

"We didn't want firefighters getting hurt for a building that was coming down anyway," Garner says. "We were very careful about that. And frankly, we were very grateful nobody got hurt."