toxic gas monitor carbon dioxide sensors gas detection voc TOXIC GAS MONITOR The EL toxic gas monitor series brings the accuracy and selectivity of electrochemical-cell sensor technology to the Acme toxic gas monitor line. Available for a wide range of hazardous and toxic gases, the EL toxic gas monitor series can be ordered with a 4-20 mA proportional output signal, and/or up to four relay contacts for fan control and alarm. Available enclosures include NEMA 3R, 4/12 and 4X, with an available panel heater.