The invention provides a method and system for conducting a continuous operation, flowing vapor phase decontamination in either an open loop or a closed loop. Using the method, a multi-component liquid decontaminant is vaporized and delivered into, through and out of a sealable enclosure by means of a carrier gas that is flowing into, through and out of said sealable enclosure. After leaving the enclosure, the vapor is captured in a cold-water bath and decomposed.The invention humidifies the carrier gas by passing it through a temperature controlled water bath to warm, or to cool, the carrier gas as necessary in order to bring the carrier gas to the desired temperature and humidity before it is combined with the vaporized sterilant and allowed to flow into the sealable enclosure. The concentration of the vapor sterilant and the percent saturation of the vapor sterilant are simultaneously controlled by controlling the rate at which the carrier gas flows and the rate at which the liquid sterilant is vaporized. A chilled mirror or other type of dew point sensor can be used to ensure that near saturation conditions are maintained during decontamination.