Abstract In February 2000, a detailed measurement campaign was conducted over a 9-day period within a mercury (Hg) cell chlor-alkali plant in the southeastern United States (US). The principal focus of this study was to determine the fugitive (non-ducted) airborne Hg emissions from the main production equipment located in the “cell building” during extended period operations, including maintenance events. Other Hg monitoring conducted in and around the plant also included surveys of process areas surrounding the cell building, measurement of Hg fluxes from soil and other exposed surfaces, and speciated Hg measurements of ambient air both “upwind” and “downwind” of the production area as well as the determination of Hg contained in output products and wastes. The study was a collaborative effort among scientists from the US Environmental Protection Agency, the US Department of Energy's Oak Ridge National Laboratory, and the University of Michigan. This paper provides a description of the facility, the rationale and design of the study, and an introduction to companion papers containing the observational data.