Common gas hazards include: Carbon Monoxide (CO), Combustible Gases, Hydrogen Sulphide (H2S), O2 (Enrichment/Deficient and Volatile Organic Compounds (VOC).  

During excavation, often underground or in confined space, there is a huge risk of gas build-up.

Miners must wear portable gas detectors at all times to warn against the threats associated with mining fossil fuels and minerals.

Methane is considered to always be present in coal mines and therefore considered a maximum risk.

Exhaust fumes from machinery operating in the mines also poses a threat.

Oxygen depletion systems can be programmed to either alarm to alert workers or trigger ventilation systems.