What type of hammer should be used when working in an atmosphere containing flammable vapor?

When working in an atmosphere containing flammable vapors, it is critical to minimize any potential sources of ignition. A non-ferrous metal hammer is the appropriate choice because it is made from metals that do not produce sparks upon impact with other metal objects. This characteristic significantly reduces the risk of igniting flammable vapors present in the environment.

Using a wooden or plastic hammer could be considered; however, they may not provide the durability or effectiveness needed for specific tasks that require a solid strike. A wooden hammer may be prone to splintering, and a plastic hammer might not deliver the necessary force for certain applications. Steel hammers, on the other hand, can produce sparks during use, which poses a significant fire hazard in a flammable atmosphere.

Therefore, the non-ferrous metal hammer is the safest and most effective option when working in environments where flammable vapors are present.