The raging fire was ignited in the early hours of Friday, near Seseña municipality in the central province of Toledo, located in the western part of the autonomous community of Castilla-La Mancha.
At least people have already left the complex, situated less than one kilometer (0.6 mile) from the torching dump.
The local government has issued a low-level catastrophe alarm due to the “extremely dangerous” and “highly carcinogenic” fumes produced by the blaze.
According to local media, ambulances were being sent to the complex to evacuate people with health problems who could not leave on their own.
About a dozen teams of firefighters are working to contain the fierce fire and two water-carrying choppers doused the burning tires throughout the day. The smoke plume could be seen from Madrid, over 30 kilometers (20 mile) away.
About 70 percent of the tires had burned by Friday night but authorities did not know when the blaze would be completely extinguished, said Francisco Martinez, the regional government’s environmental minister.
Emergency services noted that no one has been injured.
However, according to local authorities, the fire appears to have been started intentionally.