Occupational membership guides what people do, how they think of themselves, and how they interact in organizations and with society. While a rich literature explains how occupations adapt in response to external triggers for change, we have limited insight into how occupational incumbents, absent external triggers, work to influence how their peers do their work. We investigate the emergence and growth of “green chemistry,” an effort by chemists to encourage other chemists to reduce the health, safety, and environmental impacts of chemical products and processes. We find that advocates simultaneously advanced normalizing, moralizing, and pragmatizing frames for green chemistry and that each frame resonated differently with chemists in their various occupational roles. While this pluralistic approach generated broad acceptance of the change effort, it also exposed tensions, which threatened the coherence of the change. Divergent responses of advocates to these tensions contribute to a persistent state of pluralism and dynamism in the change effort. We discuss implications for theory on occupational change arising from our attention to internally-generated peer-driven change, heterogeneity within occupations, and change efforts that moralize occupational work.