Give two reasons why methane gas is dangerous in confined spaces.

Methane gas is a significant hazard in confined spaces primarily due to its potential to explode and the risk of insufficient oxygen levels. When methane accumulates in a confined area, it can reach explosive concentrations, particularly if it encounters an ignition source. Such explosions can result in catastrophic damage, injuries, or fatalities.

Additionally, the confined nature of the space can restrict the availability of oxygen. Since methane is a gas that displaces oxygen, high concentrations can lead to dangerously low oxygen levels, making it difficult for individuals to breathe. This combination of explosive potential and the risk of asphyxiation makes methane particularly dangerous in confined environments.

The other options do not address the primary dangers related to methane in confined spaces. While methane can indeed cause headaches and fatigue in high concentrations, these symptoms are secondary to the immediate life-threatening risks of explosion and oxygen displacement. Methane is not considered highly corrosive, which makes that option less relevant to its hazards. Lastly, although methane may create a visual obstruction when it accumulates, the critical concerns are the explosive nature and the oxygen displacement, rendering those other factors less significant in comparison to the primary dangers.