Emergency crews responded to the fire at the BL Duke Scrap Metal Recycling Yard on Genstar Lane around 3 p.m.
North Broadway Street is closed near Theodore Street as the Joliet Fire Department battles the blaze, Joliet police said. Drivers should look for alternate routes.
The debris fire is expected to burn through the night. At one point the flames threatened nearby buildings.
The scrap yard contained flammable liquids, and there are reports some employees were trapped when emergency crews arrived. All were safely evacuated and no injuries were reported.
Firefighters have had to dig through the burning pile of wood, plastic and metals to get to the source of the fire, fighting flames the whole way.
Crews from multiple jurisdictions, including Joliet and Lockport, responded to the scene. The firefight is being overseen by the Lockport Township Fire Protection District.
The cause of the fire remains under investigation.