There is a great need for reliable environmental sensors that can monitor the concentrations of gases and vapors such as oxygen, carbon dioxide, carbon monoxide, water vapor and other contaminants of the cabin air in a manned space station. Honeywell has developed a new class of electrochemical gas sensors based on nonaqueous electrolytes. Sensors with three electrode configuration and gold sensing electrodes have been fabricated and used for monitoring both carbon dioxide and oxygen with the capability to monitor water vapor using linear scanning voltammetry. Sensors with platinum sensing electrodes have been used to monitor low concentrations of toxic gases such as carbon monoxide and nitrogen oxides with potential capability to monitor organic contaminants. Experimental results obtained with these low-power and microprocessor-based sensors will be presented. The unique advantages of nonaqueous electrolyte-based sensors over the conventional aqueous-based sensors and semiconductor sensors will be discussed in terms of multigas sensing capability, selectivity, sensitivity, stability and operating life.