This research project examines the collaborations among local and translocal actors that focus on the possible negative impacts of aerial fumigation in Colombia. Locating myself in the southern department of Putumayo, I trace the testimonial stories produced by communities, the scientific evidence produced by epidemiologists, toxicologists and public health providers, and the witness narratives produced by humanitarian delegations as they create a field of action that they can share to document concerns about human health and rural landscapes. Recent anthropological work at the interface with science and technology studies examines the ways that information operates as an instrument of power, configuring access to knowledge, managing certainties and uncertainties, and influencing policy and decision making. I extend this analytic to ask how information is produced and mobilized in a context of impossibility where dominant aesthetics of secrecy pervade official realms and daily life. Colombia today is marked by the intense militarization of life and by humanitarian intervention to denounce violence. Among the latter, networks of collaboration are formed where actors, with distinct abilities, converge politically to turn their stories into truths that aim to disrupt official narratives about the harmlessness of fumigation. The capacity of these actors to translate their stories into a language of expertise with global reach is mediated by the interplay of very local and transnational power relations. The objective of this project is to study the relations of collaboration between different narratives and knowledges as they coalesce to produce information about the appearance of illness in bodies and soil. I seek to contribute to current studies that examine how competing global truths are produced and position people to survive the uncertainties of life under precarious conditions.