Crews remain on scene of a fire at the Waste Management transfer station located at 2400 W. Union Ave. in Englewood.
Two structures are involved in the fire, according to the Denver Fire Department. It started some time before 5:50 p.m. Monday.
The fire affected power lines, which has complicated the fire attack, the Denver Fire Department said in a tweet.
One Waste Management employee was treated by paramedics.
Denver Fire Capt. Greg Pixley confirmed around 8:30 p.m. the firefighting efforts had moved to a defensive attack.
The Englewood Police Department said Tuesday morning that firefighters were still on scene, and the fire was what was causing the smell of smoke and poor air quality in the Denver metro area. The National Weather Service in Boulder said the poor air quality is mostly to the north of the fire due to south winds.