What is the term for the unsafe buildup of gas in an enclosed space?

The term "gas accumulation" refers to the unsafe buildup of gas in an enclosed space. This accumulation can pose a significant risk of explosion or poisoning, particularly as gases like natural gas are typically colorless and odorless, making them difficult to detect without proper equipment. In an enclosed environment, the gas can reach hazardous concentrations, leading to dangerous situations for occupants.

In contrast, "gas leakage" would describe the process of gas escaping from its intended containment, while "gas rupture" pertains to a break or failure in a gas line or container, which can also lead to leaks. "Gas evacuation" refers to the process of removing gas from a space, which is a necessary response once an accumulation is detected to ensure safety. Thus, "gas accumulation" is the most accurate term to describe the issue of gas buildup in a confined area.