Workplace safety investigators spent Friday looking into how 8,000 pounds of granite slabs ended up crushing a delivery driver at a Santa Rosa business Thursday.

Six 6-by-10-foot slabs fell on the man while he unloaded a truck at Ceramic Tile Center on Santa Rosa Avenue about 1:15 p.m., according to Santa Rosa Fire Battalion Chief Ken Sebastiani.

“He suffered serious injuries,” Sebastiani said. He was rushed to Santa Rosa Memorial Hospital by ambulance and immediately went into surgery.

His condition could not be determined Friday. Santa Rosa Fire officials declined to release his name, contending the department was exempt from public records laws in such a case.

“It’s really sad what happened to him, it’s a terrible thing,” said Tyler Lewis, owner of Ceramic Tile Center.

The injured deliveryman worked for San Diego-based Arizona Tile, Lewis said. A representative from Arizona Tile who was at the scene for the Cal-OSHA investigation refused to comment.

A Cal-OSHA spokesman based in Oakland declined to release the deliveryman’s name or provide any other details about the investigation.

The delivery truck, a large flatbed fitted with a crane, was still parked by Ceramic Tile Center Friday. The granite slabs remained where they had fallen.

There were no witnesses, Lewis said, but those inside the business heard a loud bang and ran outside to find the man crushed under the granite slabs. It was the first serious incident at the company in 42 years of business, Lewis said.

Santa Rosa Fire used hydraulic tool and airbags to free the man from under the pile, Sebastiani said.

You can reach Staff Writer Nick Rahaim at 707-521-5203 or nick.rahaim@pressdemocrat.com. On Twitter @nrahaim.