A fire that heavily damaged a Kalihi auto service business last night was deliberately set, fire officials said. It was the second fire at the business in about a week.

Last night's blaze at the Firestone Tire & Service Center on Dillingham Boulevard and Waiakamilo Road was initially reported as a trash bin fire about 8:45 p.m. But the first firefighters to arrive realized that the flames had jumped from a pile of old tires just outside the building into the building itself, Honolulu Fire Department spokesman Capt. Emmit Kane said.

Additional fire companies were called and helped bring the blaze under control at 9:07 p.m. Damage to the building and its contents was estimated at $120,000, although that amount could rise as Firestone officials assess the damage.

Four vehicles parked in the work area may have suffered smoke damage. Kane said windows at an apartment unit behind the business were broken when hit by water from a fire hose.

A fire investigator was called to the scene. Kane said initial signs indicate that the fire was intentionally set.

"About a week or so ago we responded here to the same type of fire, but this time it extended a little more before anybody became aware of it," he said. "There's no exterior sources of electrical hazards or anything like that. It's just the circumstances around it that leads us to believe it was intentional, especially after what occurred last week."

The previous fire caused only minor damage. Kane said last night's fire caused significant damage to the building.

"The roof system is all trusses and this whole (mauka) side is going to have to be taken down. It's pretty extensive," he said.

Meanwhile, Kane said Monday's Salt Lake house fire that injured two elderly residents has been referred to police for investigation. In addition, there were arrests yesterday for Tuesday's fire that damaged the entrance to the state Department of Health building on Punchbowl Street. The building will be reopened to the public today.

Reach Curtis Lum at culum@honoluluadvertiser.com.