The cause of a fire at a downtown apartment-commercial building is still under investigation, according to fire officials.

Capital City Fire/Rescue Chief Richard Etheridge said in a phone interview late Tuesday afternoon that the fire marshal is investigating “multiple theories” about the Gastineau Apartments fire, which burned for a total of nine hours from about 5 p.m. Monday until 2 a.m. Tuesday.

The blaze displaced somewhere between 40 to 50 occupants of the building and prompted the American Red Cross of Alaska to set up an emergency housing and services disaster shelter in Centennial Hall. No casualties were reported.

Fire Marshal Daniel Jager narrowed down the room where the fire started, but the fire department still needs to conduct more interviews before making and disclosing an official cause ruling, Etheridge said.

Etheridge confirmed one of the theories was an unattended candle in one of the apartment rooms on the fourth story of the building, which also houses commercial businesses — a skateboard shop, a nail salon and a boutique — on its first floor.

“That is definitely a rumor we’ve heard throughout town multiple times,” Etheridge said. “But at this point, it’s still a rumor.”

Arson has not yet been ruled out as the cause of the fire, Etheridge said.

“We can’t rule it out yet, but it’s not real high on the radar,” Etheridge said. “Nothing jumps right out and indicates it was an arson. But until we’ve completely ruled it out, it’s always a possibility.”

The building was condemned on Tuesday, and also released from the responsibility of the fire department back to the building’s owner. The building, owned by James Barrett, was insured, Etheridge said.

According to the City and Borough of Juneau’s Finance Department Assessor’s Database, it was built in 1917 and had a site value of $810,200. The building property value was listed as $1,000,700, and the total property value was listed as $1,810,900, according to the database.

Etheridge estimated about $150,000 to $200,000 of personal possessions were lost in the fire.

Residents will be allowed back into the building to retrieve personal items beginning Wednesday morning. Residents need to make arrangements with Barrett to do so. Etheridge said they can reach Barrett at 790-2183 or at 902-1188.

No one will be allowed back on the fourth-floor in part because nothing is salvageable there and for safety reasons. Insurance investigators want to go through the scene untampered, Etheridge said.

The basement of the building was flooded after hours of dousing the flames with two to two and a half million gallons of water, Etheridge said.

City officials with the Public Works Department and Alaska Electric Light and Power Company worked on the building on Tuesday to pull water out of the basement. They ensured the water was turned off in the building while keeping the water supply on for other neighboring businesses, with which it shares utilities.

A portion of South Franklin Street remained cordoned off for the majority of the day to allow that work to be done. During the fire, police had barricaded off the area as seemingly hundreds of people watched the burn.

One firefighter sustained a minor, non-life threatening injury to his head during fire fighting operations, but he or she has since been treated and released from the hospital, Etheridge said.

Five civilians — three of which were transported from the scene via ambulance, and the other two walk-ins — were treated for smoke inhalation, said Jim Strader, a spokesman for Bartlett Regional Hospital. All were treated and released, Strader said.

The fire did claim one pet, a cat. A pet rat is also reported missing, but wasn’t in the area that was badly burned, Etheridge said.

Firefighters did rescue one chinchilla, which was doing fine, Etheridge reported.

Almost every firefighter in Juneau responded to the call — that’s 33 full-time paid firefighters, plus 65 volunteers, Etheridge said.

CCFR had two ladder trucks and three fire engines on scene as well as a rescue truck that was in reserve, but pulled back into service for the night.

CCFR also received outside assistance from Sitka firefighters, six of whom flew in to Juneau on a Coast Guard helicopter, Etheridge said. Retired firefighters in Juneau also helped, as well as an Anchorage firefighter who happened to be in town, Etheridge said.

Although the fire was contained to the fourth floor, Etheridge still said it was a “total loss” due to extensive water damage.

• Contact reporter Emily Russo Miller at 523-2263 or at emily.miller@juneauempire.com.