Authorities on Sunday are still trying to determine the cause of a fire that destroyed an emtpy commercial building in the heart of downtown Hayward.

The fire broke out about 2 p.m. Saturday at a building at the corner of B and Main streets in an area that has been undergoing revitalization.

"The flames took off real quick," said witness Steven Bales.

Patrons at The Bistro witnessed the fire grow quickly.

"The intensity kind of grew pretty quick. It went from smoke to flames like, woosh. Right away," said witness Ivan Alonso.

Hayward Fire called in Alameda County Fire.


"We had three crews go interior with lines they were all working and encountered heavy fire on the backside we had a partial wall collapse and a partial roof collapse, so we pulled them out and had to go defensive and that's why you see these water towers right now," said Hayward Fire Battalion Chief Mike Hildebrand.

The owners of the building said four men were working on the roof when the fire started.

"They were doing the roofing in the back of the building and that's where the fire started," said Corinne Zaracotas, co-owner of the building.

Although the building is empty, the owners say a new business was going to be opening in the building, and the business owner was just two weeks away from remodeling.

"The people have been working quite a long almost a year-and-a-half to fix it," said Tim Zaracotas, co-owner of the building.

But now the building will need to be gutted.

Business owners say the fire is a temporary set back.

"Because they see a building that's burned out and there's a lot of smoke damage and in this case a lot of water damage and people might not want to come down here to eat dinner for those reasons," said Ken Mitchell, who owns a nearby building.

Firefighters stayed on the scene throughout the night to monitor hotspots.

The cause of the fire is under investigation.