Crews pulled an all-nighter battling the blaze, which broke out at a pallet yard on the 14000 block of Slover Avenue Friday.
At the height of the fire, explosions could be heard as flames ignited propane tanks.
The fire started at around 6 p.m. and quickly spread from the pallet yard to a trucking business next door. At one point, the blaze was so big that flames were shooting 80 feet into the air.
"You've got stacked pallets pretty high in the air. We have a breeze through here. Once one lights, it continues to travel through the pile and some of these piles as you can see behind me are pretty massive," said Capt. Shawn Millerick with the San Bernardino Fire Department.
Officials said three buildings at the pallet yard were damaged or destroyed. One firefighter was hurt, but he is expected to be OK.
The cause of the blaze remains under investigation.