Crews were called out to the plant at 4661 South Ivy Street around 4 p.m.
No injuries were reported, and no surrounding buildings were damaged by the fire. It's not clear what sparked the fire.
The second-alarm fire was mostly extinguished by shortly after 6 p.m. Denver Fire said people should expect traffic in the area as mop-up efforts continued.
Final update for Second Alarm Fire at metal recycling plant 4661 Ivy. Bulk of fire extinguished but crews now working on finding hot spots. Luckily no injuries and no fire exposure to neighboring buildings. Expect traffic delays in area until all extiguishment is completed. pic.twitter.com/X54plvuxNH