In terms of confined spaces, 'Engulfment' refers to:

Engulfment is a critical concept in confined space safety that specifically refers to the condition in which a person is surrounded by material, such as liquids, loose solids, or granular substances. This situation poses significant hazards, as a person can quickly become unable to escape, leading to serious injuries or fatalities.

Understanding engulfment is crucial for safety personnel and workers entering confined spaces, as materials like sand, grain, or water can shift rapidly, creating a life-threatening environment. For example, someone working in a grain silo may be at risk of being engulfed by flowing grain if the material suddenly shifts, making awareness and training essential.

The other possible choices, while relevant to confined space issues, do not accurately define engulfment. Loss of physical safety from machinery, being trapped in small spaces, and exposure to harmful gases are all important hazards in confined spaces, but they do not specifically capture the scenario of being surrounded and potentially suffocated by material, which is at the core of engulfment.