The American Conference of Governmental Industrial Hygienists (ACGIH) and some regulatory authorities have revised their exposure limits for nickel and nickel compounds in workplaces based upon new sampling standards for inhalable nickel exposures. Others may be in the process of doing so. Safe standards for workplace exposures should utilize the most up-to-date health data on individual nickel species and should incorporate the principles of new sampling conventions that have been developed over the recent decades. The purpose of this paper is to review the basis for setting inhalable occupational exposure standards for the principal inorganic nickel species. It is hoped that this paper will (1) prompt companies in various nickel industry sectors to begin collecting the necessary inhalable aerosol measurements, speciation data, and particle-size information required to implement health-based sampling programs in the future, and (2) encourage regulators to derive species-specific, inhalable-based workplace standards for nickel and its inorganic compounds.