Aspects of the disclosure are directed to apparatuses and methods involving a desiccant chamber and related componentry, as may be utilized for controlling humidity in electrical enclosures. As may be consistent with one or more embodiments, an environmental control module (ECM) includes a desiccant chamber with a desiccant material therein, first and second membranes in a pathway extending from the desiccant chamber and through respective openings in the ECM, and a gasket and enclosure on the ECM which seal the pathway. A seal in the pathway seals the opening in ECM leading to the first membrane and desiccant chamber during evacuation and fill of an electrical enclosure in which the ECM may be employed, and can be broken to couple the desiccant to the electrical enclosure.