Strong disputes over the hazardous nature of coal combustions wastes have persisted since the 1970s, as utilities, fossil fuel lobbyists, and even many elected officials asserted its harmlessness while much of the public, environmental groups, and public interest groups stressed otherwise. The Resource Conservation and Recovery Act has two regulatory pathways that coal combustion waste could fit under, subtitle C and subtitle D. The classification of the waste as ‘hazardous’ under subtitle C has costly regulatory implications that call for stringent federal oversight of the disposal of the waste. However, subtitle D grants states almost full discretion in deciding how to manage the waste, implicating concerns over environmental federalism as many states often prioritize their economic interests over public health and environmental protection. With this in mind, this thesis will trace the political struggle over the federal regulation of coal combustion wastes from 1970 to 2015. Furthermore, it will examine the nature of coal ash catastrophes themselves and how they bring to bear conflicting risk frameworks. Ultimately, it will address what is at stake when the legal conception of hazardousness is contested by stakeholders from unequal and disparate backgrounds.