Vapor intrusion (VI) has the potential to affect over 100,000 developed and undeveloped sites in the United States. Vapor intrusion occurs when the migration of volatile chemicals from the subsurface enters overlying buildings. A myriad of adverse health effects have been documented based on the inhalation of volatile chemicals from VI. At a time when most state and federal agencies have yet to set firm standards, the burden of responsibility is often placed on the facility manager to decide how to protect building occupants from volatile organic compounds potentially seeping into buildings. This article outlines a detailed step-by-step process for facility managers on how to begin a VI assessment and, when warranted, establish a site-specific vapor intrusion management system for building occupant protection. This document should be used concurrently with current federal and state guidelines as it pertains to VI. © 2014 Wiley Periodicals, Inc.