How will big data impact environmental law in the near future? This Essay imagines one possible future for environmental law in 2030 that focuses on the implications of big data for the protection of public health from risks associated with pollution and industrial chemicals. It assumes the perspective of an historian looking back from the end of the twenty-first century at the evolution of environmental law during the late twentieth and early twenty-first centuries. The premise of the Essay is that big data will drive a major shift in the underlying knowledge practices of environmental law (along with other areas of law focused on health and safety). This change in the epistemic foundations of environmental law, it is argued, will in turn have important, far-reaching implications for environmental law’s normative commitments and for its ability to discharge its statutory responsibilities. In particular, by significantly enhancing the ability of environmental regulators to make harm more visible and more traceable, big data will put considerable pressure on previous understandings of acceptable risk across populations, pushing toward a more singular and more individualized understanding of harm. This will raise new and difficult questions regarding environmental law’s capacity to confront and take responsibility for the actual lives caught up in the tragic choices it is called upon to make. In imagining this near future, the Essay takes a somewhat exaggerated and, some might argue, overly pessimistic view of the implications of big data for environmental law’s efforts to protect public health. This is done not out of a conviction that such a future is likely, but rather to highlight some of the potential problems that may arise as big data becomes a more prominent part of environmental protection. In an age of data triumphalism, such a perspective, it is hoped, may provide grounds for a more critical engagement with the tools and knowledge practices that inform environmental law and the implications of those tools for environmental law’s ability to meet its obligations. Of course, there are other possible futures, and big data surely has the potential to make many positive contributions to environmental protection in the coming decades. Whether it will do so will depend in no small part on the collective choices we make to manage these new capabilities in the years ahead.