Initially, Midgley was viewed as a brilliant inventor who solved pressing problems in the automotive and refrigeration industries. He was celebrated for his contributions to technological advancement.

As concerns about lead poisoning grew, Midgley faced increasing criticism for his role in developing and promoting leaded gasoline. Public awareness of the health risks associated with lead exposure tarnished his image.

In recent decades, Midgley's legacy has been re-evaluated in light of the environmental damage caused by CFCs. He is now often viewed as a cautionary tale about the unintended consequences of scientific innovation.

Midgley himself defended TEL and Freon, even to the point of harming himself in order to demonstrate the apparent safeness of a product to the public.