The blaze also damaged an occupied apartment building and caused minor injuries to one firefighter.
It took 60 firefighters to attack the flames from the ground, from nearby rooftops and from a ladder engine, according to the San Bernardino County Fire Department. They contained and extinguished the fire and saved multiple occupied apartment homes surrounding the construction site.
The fire was first reported at 5:24 a.m. at a construction site near 13th Avenue and East 9th Street.
Firefighters found multiple units under construction that were already well involved in flames and called in extra crews to prevent the fire from spreading to nearby apartment buildings occupied by hundreds of people. Exposed lumber at the site contributed to the danger.
The flames spread to an attic of a nearby two-story apartment building, causing some damage and displacing 25 residents. Red Cross help was requested for those who had to leave their homes.
Eight units under construction were damaged or destroyed.
The cause of the fire remains under investigation.