This paper updates an original report written by Ross & Associates in 1993, entitled Virtual Elimination Pilot Project: Mercury Sources and Regulations. The analytical framework and organization remain largely the same, with a few notable changes. First, this paper adds a section on the global mercury reservoir as a source of mercury deposition, to incorporate new knowledge derived from scientific research published since 1993 on the behavior of mercury in the environment, especially the cycling of mercury from the oceans to the atmosphere, and its retention, chemical transformation, and long-range transport. A corresponding section on international regulations has also been included.