Not all people suffer from this though. Life does not exist on Mars. But there has been speculation that Mars surface had water some millions of years ago. But they did not sustain. As yet there has been no concrete proof.
Nuclear reactions produce radiations in the form of alpha rays, beta rays and gamma rays.
These rays have high energies and are capable of causing mutations in the cells if one is exposed to these radiations. These mutations cause mainly cancer. A person working with nuclear radiation has to wear a assigned radiation badge. If the exposure is up to a limit, then the person is asked not work in the radiation hazard zone for some time, for the sake of his health.