The objective of the study was to determine whether Washington State Department of Transportation’s winter use of road anti-icer compounds on Highway 2 in Chelan County, Washington, is having an impact on the federally endangered plant species Hackelia venusta. A controlled study was performed in the outdoor facilities at the Center for Urban Horticulture-University of Washington. This study evaluated two road anti-icer formulae available to WSDOT in the 2000-2002 winter seasons by testing the effects of different anti-icer dilutions on plant and soil parameters. Since it was not feasible to use H. venusta in a controlled study during the time of implementation, two other species were used. One species, Mertensia platyphylla, is a phylogenetic relative and the other, Eriophyllym lanatum, is a non-related ecosystem associate. From the analysis, we were able to conclude that both road anti-icers begin to have detrimental effects by causing a decrease in aboveground biomass and survival on the two plant species examined when the concentrations reached 1 part anti-icer: 100 parts solution. Given the information obtained from our study’s results, more work is needed in order to better understand the implications of these results on the effects road anti-icer formulae have on H. venusta..