text: 1,4-dioxane is a recently-identified contaminant of concern. The regulatory criteria for 1,4-dioxane is constantly changing as more is learned about this contaminant. 1,4-dioxane has a high solubility in water and a low Henry's Law constant which combine to present complex challenges associated with remediation. At ambient conditions, the physical properties of 1,4-dioxane indicate air stripping is not an efficient treatment mechanism. Recent ERH remediation results indicate that ERH creates conditions favorable for treatment. ERH remediation involves steam stripping, which historically had not been investigated for 1,4-dioxane. At ERH sites, steam stripping was observed to effectively transfer 1,4-dioxane to the vapor phase for subsequent treatment. 99.8% reductions (or greater) in 1,4-dioxane concentrations in groundwater have been documented on recent ERH remediation. Monitoring of the above grade treatment streams indicates that 95% of 1,4-dioxane remained in the vapor stream after removal from the subsurface. Furthermore, granular activated carbon has proven to be an effective 1,4-dioxane vapor treatment method.