What type of gas does a methane detector specifically identify?

Methane detectors are designed specifically to identify explosive gases, with a primary focus on methane itself. Methane is a colorless, odorless gas that is a common byproduct of underground mining operations, particularly in coal mines. Due to its flammable nature, the presence of methane poses a significant risk of explosion in mining environments. The detection of methane is critical for safety, enabling miners to take necessary precautions if levels rise to dangerous concentrations.

The other types of gases listed in the choices are not the focus of methane detectors. Carbon dioxide, while a common gas in various environments, is not specifically detected by methane detectors and has different monitoring requirements. Nitrogen and oxygen are atmospheric gases that do not relate to methane detection and involve distinct safety equipment for monitoring their levels in mines. Therefore, the identification of explosive gases, particularly methane, is the primary function of a methane detector, making it essential for the safety and operational integrity of underground mining activities.