A blaze destroyed a third-floor unit at the Island Homestead Apartments on Wyatt Way Monday evening, with smoke and water damage to other units displacing five families.

No injuries were reported.

The fire, which started on an apartment balcony, was blamed on a “flash” explosion caused when propane gas built up in a barbecue and ignited as the grill was lit.

“It happened so quickly,” said the resident identified only as Richard, who escaped injury and fled the building when he was unable to douse the fire.

The alarm was raised at about 8:20 p.m., by neighbors who heard an explosion and saw a balcony facing the building’s courtyard ablaze.

Flames ignited the building’s vinyl siding and raced up into the eaves and roof, engulfing a towering wooden structure that enclosed several chimneys. Sheets of fire gutted the structure as a column of acrid smoke drifted southward over the center of town.

The blaze drew dozens of onlookers from the complex and nearby homes in the tightly packed downtown blocks.

“There was a big bang,” said Yolanka Wulff, a resident of the nearby Madison Cottages. “My first thought was illegal fireworks. Then I heard the sirens.”

Said a resident of the mobile home park across the street: “My son came running into the house – ‘Mom! There’s a fire!’”

Crews responded from the nearby fire hall, with local volunteers supplemented by units from North Kitsap.

Firefighters were able to contain the blaze to a single apartment in the 10-unit building, one of four that make up the complex. A pumper truck hosed down other parts of the roof, while several firefighters braved a collapsing ceiling and attacked the flames from inside.

The blaze was contained in about 25 minutes, although pockets of fire continued to lick at the eaves for an hour or more.

The Bainbridge department’s ladder truck was deployed next to the building, seeing its first real action since its purchase more than a year ago.

While it wasn’t used in the fire “knockdown,” Fire Chief Jim Walkowski said the truck came into play later as crews removed building siding and applied water as a precaution against smoldering material, and as a lighting and observation platform during the investigation.

Had the interior attack not worked, the aerial platform would have been used for direct downward suppression, he said.

“It was proof positive for the aerial last night, which was good,” Walkowski said.

Two Island Homestead families spent the night in a local motel, paid for by the volunteer firefighters association; others stayed with friends and family members.

While the apartment unit was destroyed, Walkowski said firefighters were able to save a number of keepsakes and other personal effects inside.