This study was conducted in order to assess the levels of mercury (Hg) in air, soil, and plants in an area around chlor-alkali plant using mercury cells to produce chlorine gas. The output results indicated that the levels of Hg were decreased in the studied components with increasing the distance from the hot spot. Geographically, the highest levels of Hg were recorded to the prevailing wind direction i.e., Southeast direction, while the other directions West and East had the lowest levels. A wide variation in the amount of total Hg in the air samples collected at different distances around the hot spot was found. Also there was a pronounced difference in Hg concentration in soil samples depending on location and sampling time. The maximum concentrations of soil Hg were measured during February 2008 for all sampling directions. The levels of total Hg in plant samples during the period of 12 month-study were relatively narrow compared with the levels in air and soil which represented great differences in the total Hg among different directions and sites.