Humidifier sterilizers were regarded as innovative and health-promoting products; they were widespread in South Korea until 2011. However, hospitals reported mysterious deaths, and a legal investigation in April 2016 found that hundreds of people have died due to use of the sterilizing disinfectant. This article takes up that topic, discussing the government's role in dealing with the risk regarding the humidifier disinfectant. We pay particular attention to the unequal nature of the uncertainty produced by the distorted socioeconomic structure. Through in-depth interviews with key informants and an examination of relevant documents from the government, civic groups, and newspapers, we find that the government had increasingly acknowledged the risk, yet their inaction failed to stop the high number of casualties, and they have only recently responded proactively. The uncertainty of the risk was unevenly distributed between companies, the government, experts, and citizens. We argue that the proactive and transparent role of the government with the precautionary principle could fix the unequal structure of knowledge production and preserve public health.