This paper examines how ethically significant assumptions and values are embedded not only in environmental policies but also in the language of the environmental sciences. It shows, based on three case studies associated with contemporary pollution research, how the choice of scientific categories and terms can have at least four ethically significant effects: influencing the future course of scientific research; altering public awareness or attention to environmental phenomena; affecting the attitudes or behavior of key decision makers; and changing the burdens (...) of proof required for taking action in response to environmental concerns. The paper argues that deliberative forums, research-ethics training, and conceptual work by environmental philosophers could all promote more ethically sensitive responses to these features of scientific language. (shrink)