Retardation of migrating contaminant vapors in the subsurface may mitigate groundwater contamination or vapor intrusion into buildings. An experimental investigation was conducted to quantify the retardation of carbon disulfide (CS₂) vapor in moist porous media based on the analysis of concentration breakthrough curves. Findings linked retardation to types of porous media and water saturation. Moreover, the first evidence of biodegradation of the CS₂ vapor was found in the column experiments.