A City of Riverside firefighter was injured while battling a pallet fire behind a commercial building in Riverside early Sunday morning. 

The blaze was reported just after 8:30 a.m. in the 6900 block of Jurupa Avenue near Wilderness Avenue, according to a news release from the Riverside Fire Department. 

“Upon arrival, crews encountered significant fire in an exterior storage area with immediate exposure threats to adjacent commercial buildings,” the release said. “Firefighters initiated an aggressive fire attack.”

The blaze was extinguished by 9:10 a.m., firefighters said. More than 20 firefighters were called to assist with the firefight, containing the flames to the pallets and construction materials they were carrying. An estimated $720,000 in materials were damaged by the fire.

“The exterior of the building was damaged from the radiant heat of the fire and crews were able to prevent further extension into the building,” the release said. 

A firefighter was hospitalized with a moderate injury after they experienced a “medical emergency,” according to the release. 

The cause of the fire remains under investigation and no other injuries were reported.