Corporate misconduct is often associated with environmental, political, and social problems, and the effects are often felt at the local level where disenfranchised residents may have less access to political power. We know that grassroots movements can take various tactical paths as they challenge elites, yet we aim to map the specific pathways that lead to shifts in tactical repertoires, especially as groups transition to increasingly confrontational tactics. Drawing from social movement theory on tactics and targets, along with environmental sociology literature on grassroots environmental organizing, we examine how the interplay with institutional movement targets affects local environmental resistance. The data for this research come from numerous sources, including in-depth interviews, archival materials, and news coverage of petrochemical contamination. Our findings show that grassroots shifts from insider to outsider tactics stem from a loss of trust in elite institutions and citizens’ understanding of the organization of power in society. We conclude by discussing how our research informs future social movement research by adding an important dimension to analyses of movement tactics—namely, the perceived relationship between activists and their institutional targets.