Every person hired by CERN (staff member/fellow/apprentice), whatever the type or duration of their contract, has to undergo an obligatory medical examination of pre-employment. A calendar for the next visit is established during this consultation - according to the occupational hazards the person is exposed to, the person's own individual health history and his or her family antecedents . The calendar for future visits is modified according to changes that occur during the person's professional or personal life.
On taking up his or her employment, the new member of personnel must fill in an Occupational Hazards Questionnaire. This questionnaire is updated regularly at the time of each medical examination.