Which person uses a safety lamp?

An underground miner. Mines- especially coal mines- may have an ignitable gas known as "fire damp". This is methane gas, and can be highly explosive. Early miner's lamps had an open flame, and could ignite that. The Davies Safety Lamp would not. Today we use electric lamps that are safe to use in areas with methane, but you can still see the early safety lamps in mining museums.