Elephants have extraordinary memories and it has been demonstrated over and over again that they never forget rough treatment by human handlers. Consequently, they can pose an unpredictable and abiding danger to the public, to their handlers, and thus to themselves.
Every year circus activities lead to people being injured. Circuses around the world have since the 1990s been responsible for over 100 human injuries.
Furthermore, circus elephants may carry the bacterial and contagiues (also to humans) disease tuberculosis (TB). In the US public records show that many circuses have used TB-positive elephants in performances.