In a flammable atmosphere, the best type of power tools to use are:

Using air-driven power tools in a flammable atmosphere is the most prudent choice because these tools do not generate sparks or heat that could ignite combustible materials. Air-driven tools operate using compressed air, which means there are no electrical components involved that could create an ignition source, making them inherently safer in environments where flammable vapors or dust may be present.

In contrast, battery-powered tools, while they may minimize spark production compared to traditional electric tools, still have the potential for electrical faults or short circuits that could lead to sparks. Electric tools, particularly those with brushes or certain types of motors, can generate heat and sparks as well, posing a risk in a flammable atmosphere. Therefore, air-driven tools offer a reliable option for reducing the risk of ignition in hazardous environments.