Fire heavily damaged the Bob's Big Boy restaurant at 2828 Pa'a Street yesterday morning while the restaurant was closed. Fire officials made an initial damage estimate of $1 million to the building and $500,000 to the contents.

Eight fire companies and about three dozen firefighters responded to the 2:50 a.m. alarm. The fire was brought under control by 3:36 a.m. and extinguished by 5:19 a.m. No injuries were reported.

It was not immediately known what started the fire.

Fire Capt. Robert Main said firefighters had to cut through the building's roof to reach parts that appeared to be centered in the restaurant's kitchen area and the exhaust ducts above.

Fire damage was limited primarily to the kitchen although much of the restaurant sustained heavy smoke damage, Main said.

No one was in the building at the time of the fire, Main said. It closed for the night at midnight and the last employee left about 1 a.m., Main said.