This technical review document, prepared by the United Nations Environment Program (UNEP), addresses the environmental aspects of nickel production, specifically pyrometallurgy and nickel refining. The major topics considered in this document include: a brief description of main processes and pollutants; the working environment and its protection; environmental effects of air emissions, air pollution control; water pollution control; regulatory control; considerations in planning nickel smelters and refineries; and retrofitting oil smelters. This technical review is addressed to plant engineers and managers or government officers responsible for pollution control and abatement of nickel production.