A gas detector is a safety instrument designed to detect and measure the presence of harmful or combustible gases in the environment, helping to prevent accidents such as poisoning, fire, or explosion. It works using sensors that identify specific gases like carbon monoxide, hydrogen sulfide, methane, or oxygen levels and provide audible, visual, or vibration alarms when dangerous concentrations are reached. Gas detectors may be portable for personal safety or fixed for continuous monitoring in industrial areas. They are widely used in oil and gas plants, mining, chemical industries, laboratories, sewage systems, and confined spaces. These devices are essential for ensuring workplace safety, environmental protection, and compliance with safety regulations.