IR21EJ is an analog infrared single gas sensor for mining. The SGX infrared sensor uses the proven Non-Dispersive Infrared (NDIR) principle to detect and monitor the presence of gases. With an infrared source and specific filtering on the pyroelectric detectors mounted inside the optical/gas cavity, individual gases or types of gas can be identified and their concentrations determined. This sensor is suitable for reliable monitoring of gas levels in mining applications where the sensor size is restricted and require a flameproof enclosure for the hazardous environment.