Abstract: A new and improved gas detecting and warning system of the type employing a metal oxide semiconductor gas detector device and which incorporates a quad comparator integrated circuit means having four independent comparator sections. One of the sections is arranged with the gas detector device to provide a digital limit detector operative to produce an output and a warning alarm whenever the voltage developed across a load resistance in series with the gas detector device exceeds a predetermined value. Another comparator section is arranged with an R-C timing circuit to inhibit operation of the warning alarm for a predetermined time after system energization to prevent false alarms during the initial warm up of the gas detector device. The other two comparator sections are arranged to cause intermittent energization of the warning alarm if there is a failure or malfunction of the gas detector device and/or a failure of its associated components.