Investigation of professional nickel exposure in nickel refinery workers.

For assessing the real exposure level of nickel in electrolytical nickel production workers we monitored the following indicators of Ni load. (a) Stationary air sampling of Ni, (b) personal air sampling of Ni, (c) urine Ni excretion determined on group basis, (d) the 4 hours specimen of Ni excretion determined on an individual basis. A tentative limit for Ni in urine, roughly corresponding to the MAC 0.