Fire crews were responding to the scene at the business in the 4600 block of E. State Street. The flames were deemed a second-alarm fire and were later upgraded to a third-alarm blaze.
Montclair police said two homes were completely destroyed by the blaze. One additional home and three detached garages were also partially damaged, officials said.
In total, six structures were impacted by the fire before the flames were 100 percent contained by 5 p.m., fire officials said.
Fire officials said it would take hours before fire crews could go inside the recycling center to clear what is left of the blaze due to the materials in the area, including vehicles and other salvaged materials.
"...This is a salvage yard so trying to determine what is burning - there could be a whole host of hazards," said Kelley Donaldson of the Rancho Cucamonga Fire Department. "So the firefighters do need to take that into consideration as they are attacking the fire, as well as how they are progressing into the area."
Multiple images on social media showed large flames and plumes of smoke shooting up to the sky.
Police said eight homes, a mobile home park, motel and 40 other apartments near the scene were all evacuated as fire crews from Montclair, Ontario, Upland, Rancho Cucamonga and Los Angeles battled the stubborn blaze.
Fire officials said one civilian was injured. He or she was transported to a nearby hospital in unknown condition.
Fire crews from Ontario, Upland, Rancho Cucamonga and Los Angeles all assisted in the firefight.
The westbound lanes of Mission Boulevard were shut down for several hours as crews battled and cleaned up the mess in the area.