Firefighters on Sunday night were battling a massive blaze at a 10-acre pallet yard in Fontana, officials said.
A caller reported the three-alarm fire at 9:50 p.m. in the 13800 block of Slover Avenue, said Tracy Martinez, spokeswoman for the San Bernardino County Fire Department.
There was a danger that the flames might spread to nearby homes or vegetation, Martinez said.
There were no immediate reports of injuries.
The cause of the blaze was unknown.