A hazardous gas detection system includes a first and second plurality of air sampling ports in fluid communication with an exhaust duct of a gas turbine enclosure. The first and second plurality of air sampling ports is fluidly connected to a first and second outlet orifice respectfully. A primary sensor is in fluid communication with the first outlet orifice and a secondary sensor is in fluid communication with the second outlet orifice. The primary and secondary sensors generate signals indicative of hazardous gas concentrations in first and second aggregated exhaust air samples. A computing device monitors the hazardous gas concentrations, monitors functionality of the primary and secondary sensors and generates a command signal indicating an operating mode for the gas turbine based on at least one of the hazardous gas concentrations in the first and second aggregated exhaust air samples and the functionality of the primary and secondary sensors.