Per- and polyfluoroalkyl substances (PFAS) contamination is an emerging environmental and public health crisis. Thus, it is crucial to understand public risk perception and communication behaviors surrounding this issue. Guided by the heuristic-systematic model of information processing, this study explores the impact of conflicting information and personal relevance on information insufficiency and information processing. Through an online experiment, 1,062 U.S. adults were randomly assigned to one of four conditions as part of a 2 (information type: conflicting vs. consistent) × 2 (personal relevance: high vs. low) between-subjects factorial design. Both main effect and interaction effect were detected. Specifically, information insufficiency was highest among participants in the high personal relevance and consistent information condition. Personal relevance also had a main effect on information processing. Conflicting information indirectly elevated information processing through increased information insufficiency, but only when personal relevance was low. These findings suggest the importance of providing consistent and personally relevant information related to the risk of PFAS contamination.