A gas detection system detects the presence of gases in an area, often as part of a safety system. A gas detection system can alert operators who are in the vicinity of the leak. Can detect combustible, flammable, and toxic gases, as well as oxygen depletion. Widely used in industry and found in places such as oil rigs to monitor manufacturing processes and emerging technologies such as photovoltaics. Could be useful in firefighting.

Gas detectors are classified into two types: portable devices and fixed gas detectors. Portable detectors monitor the environment around personnel and are either hand-held or worn on clothing or a belt/harness. Fixed type detectors installed near the process area of a plant, control room, or other protected area.