Firefighters responded to the fire at 3:32 a.m. and found the former Valle Vista Skating Center at 29228 Mission Blvd. fully engulfed in flames.
"The first rig arrived in less than four minutes and encountered a high volume of fire," Hayward fire Chief Craig Bueno said. "There were flames from left to right all across the storefront."
It took 36 firefighters to contain the blaze, and the flames were knocked down at about 4:15 a.m., Bueno said.
Fire departments from Newark, Union City and Fremont assisted the city by responding to other emergency calls as Hayward firefighters battled the blaze.
The fire temporarily closed Mission Boulevard between Industrial Parkway and Tennyson Road. The street reopened at7:26 a.m.
The building, estimated by officials to be about 50,000 square feet, is a total loss, Bueno said. Only the frame of the building remains.
Investigators are treating the fire as suspicious.
"We have solid information to believe the fire may have been caused by an arsonist," Bueno said.
There were no immediate reports of injuries, according to Bueno, who said the building had been shut down for several years and was known to be utilized by homeless.
"It has a history of being occupied by transients," he said. "We haven't ruled out any civilian injuries."
Wire services contributed to this report.
Kristofer Noceda can be reached at 510-293-2479 or firstname.lastname@example.org.