Emergency declarations are a vital legal authority that can activate funds, personnel, and material and change the legal landscape to aid in the response to a public health threat. Traditionally, declarations have been used against immediate and unforeseen threats such as hurricanes, tornadoes, wildfires, and pandemic influenza. Recently, however, states have used emergency declarations to address public health issues that have existed in communities for months and years and have risk factors such as poverty and substance misuse. Leaders in these states have chosen to use emergency powers that are normally reserved for sudden catastrophes to address these enduring public health issues. This article will explore emergency declarations as a legal mechanism for response; describe recent declarations to address hepatitis A and the opioid overdose epidemic; and seek to answer the question of whether it is appropriate to use emergency powers to address public health issues that are not traditionally the basis for an emergency declaration.