This article offers an ecocritical reading of Todd Haynes’ film Dark Waters (2019) in relation to questions of slow violence, genre, environmental activism, and what is known in Hollywood as ‘Social Impact Entertainment’ (SIE). The article examines how the film’s rhetorical strategies – ultimately seeking to inspire audiences to take political action – elicit embodied, affective responses to the environmental injustices depicted on screen. Yet, as the article argues, an analysis of the film and the activist campaign that accompanied its release reveals various tensions regarding the potential of SIE films to resist corporate power and effect long-lasting social change.