As activists from historically marginalized communities advocate for themselves when confronted with increasing environmental and social injustices, students and scholars are uniquely poised to collect examples of, learn from, and amplify activists’ rhetorical efforts at intervention. This article argues for activist archival work in which researchers collect examples of activist interventions as a critical form of community engagement. The case study presented here, which focuses on local activist writing (broadly conceived) in response to the Flint water crisis, illustrates one possibility for how activist archival research might be undertaken. Specifically, it highlights the tactics of black and working-class community members who joined together to make apparent how water contamination was affecting their own bodies, families, and communities through complex, multimodal interventions online and in the Flint community. Furthermore, this article emphasizes why such research is necessary and important, particularly when the embodied, scientific, and cultural knowledges of marginalized community members are represented little, if at all, in mainstream media coverage and normative rhetorics of risk.