During the 1960s, Sarnia was the wealthiest city in Ontario and the one with the dirtiest air. Its economy was dominated by Chemical Valley, the city’s petrochemical industry. Chemical Valley firms and executives were civically active, donating to public causes, dominating the local chamber of commerce, and working closely with provincial and municipal officials to ensure a friendly business environment. They also maintained a monopoly on information about local air pollution levels and were not required by government to adhere to clean air regulations. However, like the rest of the chemical industry at the time, Chemical Valley was exposed to an onslaught of negative publicity, raising the threat of regulation and loss of their control over emissions data and production processes. This article illustrates how economic elites in Sarnia prevented the problematization and regulation of air pollution. In doing so, it describes the actors in the policy system and examines its recourse to suppress dissent when activists sought to raise the air pollution issue.