Occupational diseases are always preventable. Not every employee can avoid working with contaminants, but you should be protected from contracting diseases through proper safety measures. It is also important to get regular physical exams.
OSHA has standards employers must follow for employees who work with asbestos. However, asbestos is not the only cause of occupational diseases. If you are exposed to any irritants or chemicals you should make sure you are getting physical exams and discussing potential issues with your doctor.