The Dark side of Science: The horror of the Tuskegee Syphilis Experiment (Short Documentary)

Where would you rate this experiment on my Ethical Scale? 1 being ok, 10 being pure evil? Is it worse or better than the Lobotomy.

The Tuskegee Experiment or Tuskegee Syphilis Study was an ethically unsound study conducted between 1932 and 1972 in Alabama USA by the United States Public Health Service and the Centers for Disease Control and Prevention on a group of nearly 400 African Americans with syphilis.